[linux] 01/01: Update fix for CVE-2017-1000364 (Closes: #865303)
debian-kernel at lists.debian.org
debian-kernel at lists.debian.org
Tue Jun 27 01:26:14 UTC 2017
This is an automated email from the git hooks/post-receive script.
benh pushed a commit to branch wheezy-security
in repository linux.
commit 93b922e93fc4c8d6e342735c9b9f88b794798f75
Author: Ben Hutchings <ben at decadent.org.uk>
Date: Mon Jun 26 18:57:49 2017 +0100
Update fix for CVE-2017-1000364 (Closes: #865303)
---
debian/changelog | 8 +
.../all/mm-allow-to-configure-stack-gap-size.patch | 129 --
.../mm-do-not-collapse-stack-gap-into-thp.patch | 56 -
.../bugfix/all/mm-enlarge-stack-guard-gap.patch | 489 -------
.../mm-larger-stack-guard-gap-between-vmas.patch | 1512 ++++++++++++++++++++
...-the-stack-gap-for-unpopulated-growing-vm.patch | 45 -
...-stack-guard-gap-between-vmas-arm-topdown.patch | 68 +
debian/patches/series | 6 +-
8 files changed, 1590 insertions(+), 723 deletions(-)
diff --git a/debian/changelog b/debian/changelog
index 516cf84..67d0639 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,11 @@
+linux (3.2.89-2) wheezy-security; urgency=high
+
+ * Revert previous fixes for CVE-2017-1000364 (Closes: #865303)
+ * mm: larger stack guard gap, between vmas (CVE-2017-1000364)
+ * mm: larger stack guard gap, between vmas - ARM topdown case
+
+ -- Ben Hutchings <ben at decadent.org.uk> Mon, 26 Jun 2017 18:57:49 +0100
+
linux (3.2.89-1) wheezy-security; urgency=high
* New upstream stable update:
diff --git a/debian/patches/bugfix/all/mm-allow-to-configure-stack-gap-size.patch b/debian/patches/bugfix/all/mm-allow-to-configure-stack-gap-size.patch
deleted file mode 100644
index 5d4de23..0000000
--- a/debian/patches/bugfix/all/mm-allow-to-configure-stack-gap-size.patch
+++ /dev/null
@@ -1,129 +0,0 @@
-From: Michal Hocko <mhocko at suse.com>
-Date: Wed, 14 Jun 2017 08:17:02 +0200
-Subject: mm: allow to configure stack gap size
-Bug-Debian: https://security-tracker.debian.org/tracker/CVE-2017-1000364
-
-Add a kernel command line option (stack_guard_gap) to specify the stack
-gap size (in page unites) and export the value in /proc/<pid>/smaps for
-stack vmas. This might be used for special applications like CRIU/RR.
-
-Suggested-by: Linus Torvalds <torvalds at linux-foundation.org>
-Signed-off-by: Michal Hocko <mhocko at suse.com>
-[carnil: backport to 3.16
- - context adjustment
- - adjust location for documentation
- - is_stack -> vm_is_stack]
-[bwh: Backported to 3.2: fold in later change to use has_gap, as we don't
- have vm_is_stack()
----
- Documentation/kernel-parameters.txt | 7 +++++++
- fs/proc/task_mmu.c | 21 ++++++++++++++++-----
- mm/mmap.c | 13 +++++++++++++
- 3 files changed, 36 insertions(+), 5 deletions(-)
-
---- a/Documentation/kernel-parameters.txt
-+++ b/Documentation/kernel-parameters.txt
-@@ -2463,6 +2463,13 @@ bytes respectively. Such letter suffixes
- spia_pedr=
- spia_peddr=
-
-+ stack_guard_gap= [MM]
-+ override the default stack gap protection. The value
-+ is in page units and it defines how many pages prior
-+ to (for stacks growing down) resp. after (for stacks
-+ growing up) the main stack are reserved for no other
-+ mapping. Default value is 256 pages.
-+
- stacktrace [FTRACE]
- Enabled the stack tracer on boot up.
-
---- a/fs/proc/task_mmu.c
-+++ b/fs/proc/task_mmu.c
-@@ -210,7 +210,8 @@ static int do_maps_open(struct inode *in
- return ret;
- }
-
--static void show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
-+static void
-+show_map_vma(struct seq_file *m, struct vm_area_struct *vma, bool *has_gap)
- {
- struct mm_struct *mm = vma->vm_mm;
- struct file *file = vma->vm_file;
-@@ -232,11 +233,17 @@ static void show_map_vma(struct seq_file
- start = vma->vm_start;
- end = vma->vm_end;
- if (vma->vm_flags & VM_GROWSDOWN) {
-- if (stack_guard_area(vma, start))
-+ if (stack_guard_area(vma, start)) {
- start += stack_guard_gap;
-+ if (has_gap)
-+ *has_gap = true;
-+ }
- } else if (vma->vm_flags & VM_GROWSUP) {
-- if (stack_guard_area(vma, end))
-+ if (stack_guard_area(vma, end)) {
- end -= stack_guard_gap;
-+ if (has_gap)
-+ *has_gap = true;
-+ }
- }
-
- seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
-@@ -285,7 +292,7 @@ static int show_map(struct seq_file *m,
- struct proc_maps_private *priv = m->private;
- struct task_struct *task = priv->task;
-
-- show_map_vma(m, vma);
-+ show_map_vma(m, vma, NULL);
-
- if (m->count < m->size) /* vma is copied successfully */
- m->version = (vma != get_gate_vma(task->mm))
-@@ -440,6 +447,7 @@ static int show_smap(struct seq_file *m,
- .mm = vma->vm_mm,
- .private = &mss,
- };
-+ bool has_gap = false;
-
- memset(&mss, 0, sizeof mss);
- mss.vma = vma;
-@@ -447,7 +455,7 @@ static int show_smap(struct seq_file *m,
- if (vma->vm_mm && !is_vm_hugetlb_page(vma))
- walk_page_range(vma->vm_start, vma->vm_end, &smaps_walk);
-
-- show_map_vma(m, vma);
-+ show_map_vma(m, vma, &has_gap);
-
- seq_printf(m,
- "Size: %8lu kB\n"
-@@ -480,6 +488,9 @@ static int show_smap(struct seq_file *m,
- (vma->vm_flags & VM_LOCKED) ?
- (unsigned long)(mss.pss >> (10 + PSS_SHIFT)) : 0);
-
-+ if (has_gap)
-+ seq_printf(m, "Stack_Gap: %8lu kB\n", stack_guard_gap >>10);
-+
- if (m->count < m->size) /* vma is copied successfully */
- m->version = (vma != get_gate_vma(task->mm))
- ? vma->vm_start : 0;
---- a/mm/mmap.c
-+++ b/mm/mmap.c
-@@ -1799,6 +1799,19 @@ int expand_downwards(struct vm_area_stru
- /* enforced gap between the expanding stack and other mappings. */
- unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT;
-
-+static int __init cmdline_parse_stack_guard_gap(char *p)
-+{
-+ unsigned long val;
-+ char *endptr;
-+
-+ val = simple_strtoul(p, &endptr, 10);
-+ if (!*endptr)
-+ stack_guard_gap = val << PAGE_SHIFT;
-+
-+ return 0;
-+}
-+__setup("stack_guard_gap=", cmdline_parse_stack_guard_gap);
-+
- /*
- * Note how expand_stack() refuses to expand the stack all the way to
- * abut the next virtual mapping, *unless* that mapping itself is also
diff --git a/debian/patches/bugfix/all/mm-do-not-collapse-stack-gap-into-thp.patch b/debian/patches/bugfix/all/mm-do-not-collapse-stack-gap-into-thp.patch
deleted file mode 100644
index 06b3134..0000000
--- a/debian/patches/bugfix/all/mm-do-not-collapse-stack-gap-into-thp.patch
+++ /dev/null
@@ -1,56 +0,0 @@
-From: Michal Hocko <mhocko at suse.com>
-Date: Wed, 14 Jun 2017 08:18:00 +0200
-Subject: mm: do not collapse stack gap into THP
-Bug-Debian: https://security-tracker.debian.org/tracker/CVE-2017-1000364
-
-Oleg has noticed that khugepaged will happilly collapse stack vma (as
-long as it is not an early stack - see is_vma_temporary_stack) and
-it might effectively remove the stack gap area as well because a larger
-part of the stack vma is usually populated. The same applies to the
-page fault handler.
-
-Fix this by checking stack_guard_area when revalidating a VMA
-in hugepage_vma_revalidate. We do not want to hook/replace
-is_vma_temporary_stack() check because THP might be still useful for
-stack, all we need is excluding the gap from collapsing into a THP.
-
-Also check the to-be-created THP in do_huge_pmd_anonymous_page to
-make sure it is completely outside of the gap area because we we could
-create THP covering the gap area.
-
-Noticed-by: Oleg Nesterov <oleg at redhat.com>
-Signed-off-by: Michal Hocko <mhocko at suse.com>
-[carnil: backport to 3.16: move stack_guard_area check to huge_memory.c
-in collapse_huge_page]
-[bwh: Backported to 3.2:
- - Use 'goto' rather than 'return VM_FAULT_FALLBACK' to fall back to PTEs
- - Adjust context]
----
- mm/huge_memory.c | 7 +++++++
- 1 file changed, 7 insertions(+)
-
-diff --git a/mm/huge_memory.c b/mm/huge_memory.c
-index d6e6cafdb2c9..ef201fe46804 100644
---- a/mm/huge_memory.c
-+++ b/mm/huge_memory.c
-@@ -680,6 +680,9 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
- pte_t *pte;
-
- if (haddr >= vma->vm_start && haddr + HPAGE_PMD_SIZE <= vma->vm_end) {
-+ if (stack_guard_area(vma, haddr) ||
-+ stack_guard_area(vma, haddr + HPAGE_PMD_SIZE))
-+ goto out;
- if (unlikely(anon_vma_prepare(vma)))
- return VM_FAULT_OOM;
- if (unlikely(khugepaged_enter(vma, vma->vm_flags)))
-@@ -1922,6 +1925,10 @@ static void collapse_huge_page(struct mm_struct *mm,
- goto out;
- if (!hugepage_vma_check(vma))
- goto out;
-+
-+ /* never try to collapse stack gap */
-+ if (stack_guard_area(vma, hstart) || stack_guard_area(vma, hend))
-+ goto out;
- pgd = pgd_offset(mm, address);
- if (!pgd_present(*pgd))
- goto out;
diff --git a/debian/patches/bugfix/all/mm-enlarge-stack-guard-gap.patch b/debian/patches/bugfix/all/mm-enlarge-stack-guard-gap.patch
deleted file mode 100644
index 4f227dd..0000000
--- a/debian/patches/bugfix/all/mm-enlarge-stack-guard-gap.patch
+++ /dev/null
@@ -1,489 +0,0 @@
-From: Michal Hocko <mhocko at suse.com>
-Date: Wed, 14 Jun 2017 08:16:54 +0200
-Subject: mm: enlarge stack guard gap
-Bug-Debian: https://security-tracker.debian.org/tracker/CVE-2017-1000364
-
-Stack guard page is a useful feature to reduce a risk of stack smashing
-into a different mapping. We have been using a single page gap which
-is sufficient to prevent having stack adjacent to a different mapping.
-But this seems to be insufficient in the light of the stack usage in
-the userspace. E.g. glibc uses as large as 64kB alloca() in many
-commonly used functions. Others use constructs liks gid_t
-buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN.
-
-This will become especially dangerous for suid binaries and the default
-no limit for the stack size limit because those applications can be
-tricked to consume a large portion of the stack and a single glibc call
-could jump over the guard page. These attacks are not theoretical,
-unfortunatelly.
-
-Make those attacks less probable by increasing the stack guard gap
-to 1MB (on systems with 4k pages but make it depend on the page size
-because systems with larger base pages might cap stack allocations in
-the PAGE_SIZE units) which should cover larger alloca() and VLA stack
-allocations. It is obviously not a full fix because the problem is
-somehow inherent but it should reduce attack space a lot. One could
-argue that the gap size should be configurable from the userspace but
-that can be done later on top when somebody finds that the new 1MB is
-not suitable or even wrong for some special case applications.
-
-Implementation wise, get rid of check_stack_guard_page and move all the
-guard page specific code to expandable_stack_area which always tries to
-guarantee the gap. do_anonymous_page then just calls expand_stack. Also
-get rid of stack_guard_page_{start,end} and replace them with
-stack_guard_area to handle stack population and /proc/<pid>/[s]maps.
-
-This should clean up the code which is quite scattered currently
-and therefore justify the change.
-
-Signed-off-by: Michal Hocko <mhocko at suse.com>
-[carnil: backport for 3.16:
- - vmf->address -> address;
- - context adjustment;
- - backport for pre-"FOLL_MLOCK"-"FOLL_POPULATE"-rename]
-[bwh: Backported to 3.2:
- - stack_guard_area() replaces local stack_guard_page() function
- - Use #ifndef instead of IS_ENABLED() to test CONFIG_STACK_GROWSUP
- - Adjust filename, context
----
- arch/ia64/mm/fault.c | 2 +-
- fs/exec.c | 9 ++-
- fs/proc/task_mmu.c | 11 ++--
- include/linux/mm.h | 40 +++----------
- mm/memory.c | 46 ++-------------
- mm/mmap.c | 158 +++++++++++++++++++++++++++++++++++++++++----------
- 6 files changed, 158 insertions(+), 108 deletions(-)
-
---- a/arch/ia64/mm/fault.c
-+++ b/arch/ia64/mm/fault.c
-@@ -200,7 +200,7 @@ ia64_do_page_fault (unsigned long addres
- */
- if (address > vma->vm_end + PAGE_SIZE - sizeof(long))
- goto bad_area;
-- if (expand_upwards(vma, address))
-+ if (expand_upwards(vma, address, 0))
- goto bad_area;
- }
- goto good_area;
---- a/fs/exec.c
-+++ b/fs/exec.c
-@@ -196,7 +196,7 @@ static struct page *get_arg_page(struct
-
- #ifdef CONFIG_STACK_GROWSUP
- if (write) {
-- ret = expand_downwards(bprm->vma, pos);
-+ ret = expand_downwards(bprm->vma, pos, 0);
- if (ret < 0)
- return NULL;
- }
-@@ -210,6 +210,13 @@ static struct page *get_arg_page(struct
- unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start;
- struct rlimit *rlim;
-
-+ /*
-+ * GRWOSUP doesn't really have any gap at this stage because we grow
-+ * the stack down now. See the expand_downwards above.
-+ */
-+#ifndef CONFIG_STACK_GROWSUP
-+ size -= stack_guard_gap;
-+#endif
- acct_arg_size(bprm, size / PAGE_SIZE);
-
- /*
---- a/fs/proc/task_mmu.c
-+++ b/fs/proc/task_mmu.c
-@@ -230,11 +230,14 @@ static void show_map_vma(struct seq_file
-
- /* We don't show the stack guard page in /proc/maps */
- start = vma->vm_start;
-- if (stack_guard_page_start(vma, start))
-- start += PAGE_SIZE;
- end = vma->vm_end;
-- if (stack_guard_page_end(vma, end))
-- end -= PAGE_SIZE;
-+ if (vma->vm_flags & VM_GROWSDOWN) {
-+ if (stack_guard_area(vma, start))
-+ start += stack_guard_gap;
-+ } else if (vma->vm_flags & VM_GROWSUP) {
-+ if (stack_guard_area(vma, end))
-+ end -= stack_guard_gap;
-+ }
-
- seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
- start,
---- a/include/linux/mm.h
-+++ b/include/linux/mm.h
-@@ -1015,34 +1015,6 @@ int set_page_dirty(struct page *page);
- int set_page_dirty_lock(struct page *page);
- int clear_page_dirty_for_io(struct page *page);
-
--/* Is the vma a continuation of the stack vma above it? */
--static inline int vma_growsdown(struct vm_area_struct *vma, unsigned long addr)
--{
-- return vma && (vma->vm_end == addr) && (vma->vm_flags & VM_GROWSDOWN);
--}
--
--static inline int stack_guard_page_start(struct vm_area_struct *vma,
-- unsigned long addr)
--{
-- return (vma->vm_flags & VM_GROWSDOWN) &&
-- (vma->vm_start == addr) &&
-- !vma_growsdown(vma->vm_prev, addr);
--}
--
--/* Is the vma a continuation of the stack vma below it? */
--static inline int vma_growsup(struct vm_area_struct *vma, unsigned long addr)
--{
-- return vma && (vma->vm_start == addr) && (vma->vm_flags & VM_GROWSUP);
--}
--
--static inline int stack_guard_page_end(struct vm_area_struct *vma,
-- unsigned long addr)
--{
-- return (vma->vm_flags & VM_GROWSUP) &&
-- (vma->vm_end == addr) &&
-- !vma_growsup(vma->vm_next, addr);
--}
--
- extern unsigned long move_page_tables(struct vm_area_struct *vma,
- unsigned long old_addr, struct vm_area_struct *new_vma,
- unsigned long new_addr, unsigned long len);
-@@ -1462,16 +1434,22 @@ unsigned long ra_submit(struct file_ra_s
- struct address_space *mapping,
- struct file *filp);
-
-+extern unsigned long stack_guard_gap;
- /* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */
- extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
-+extern int stack_guard_area(struct vm_area_struct *vma, unsigned long address);
-
- /* CONFIG_STACK_GROWSUP still needs to to grow downwards at some places */
- extern int expand_downwards(struct vm_area_struct *vma,
-- unsigned long address);
-+ unsigned long address, unsigned long gap);
-+unsigned long expandable_stack_area(struct vm_area_struct *vma,
-+ unsigned long address, unsigned long *gap);
-+
- #if VM_GROWSUP
--extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);
-+extern int expand_upwards(struct vm_area_struct *vma,
-+ unsigned long address, unsigned long gap);
- #else
-- #define expand_upwards(vma, address) (0)
-+ #define expand_upwards(vma, address, gap) (0)
- #endif
-
- /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
---- a/mm/memory.c
-+++ b/mm/memory.c
-@@ -1605,12 +1605,6 @@ no_page_table:
- return page;
- }
-
--static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr)
--{
-- return stack_guard_page_start(vma, addr) ||
-- stack_guard_page_end(vma, addr+PAGE_SIZE);
--}
--
- /**
- * __get_user_pages() - pin user pages in memory
- * @tsk: task_struct of target task
-@@ -1763,7 +1757,7 @@ int __get_user_pages(struct task_struct
-
- /* For mlock, just skip the stack guard page. */
- if (foll_flags & FOLL_MLOCK) {
-- if (stack_guard_page(vma, start))
-+ if (stack_guard_area(vma, start))
- goto next_page;
- }
- if (foll_flags & FOLL_WRITE)
-@@ -3121,39 +3115,7 @@ out_release:
- return ret;
- }
-
--/*
-- * This is like a special single-page "expand_{down|up}wards()",
-- * except we must first make sure that 'address{-|+}PAGE_SIZE'
-- * doesn't hit another vma.
-- */
--static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address)
--{
-- address &= PAGE_MASK;
-- if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) {
-- struct vm_area_struct *prev = vma->vm_prev;
-
-- /*
-- * Is there a mapping abutting this one below?
-- *
-- * That's only ok if it's the same stack mapping
-- * that has gotten split..
-- */
-- if (prev && prev->vm_end == address)
-- return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM;
--
-- return expand_downwards(vma, address - PAGE_SIZE);
-- }
-- if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
-- struct vm_area_struct *next = vma->vm_next;
--
-- /* As VM_GROWSDOWN but s/below/above/ */
-- if (next && next->vm_start == address + PAGE_SIZE)
-- return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM;
--
-- return expand_upwards(vma, address + PAGE_SIZE);
-- }
-- return 0;
--}
-
- /*
- * We enter with non-exclusive mmap_sem (to exclude vma changes,
-@@ -3175,8 +3137,10 @@ static int do_anonymous_page(struct mm_s
- return VM_FAULT_SIGBUS;
-
- /* Check if we need to add a guard page to the stack */
-- if (check_stack_guard_page(vma, address) < 0)
-- return VM_FAULT_SIGSEGV;
-+ if (stack_guard_area(vma, address)) {
-+ if (expand_stack(vma, address) < 0)
-+ return VM_FAULT_SIGSEGV;
-+ }
-
- /* Use the zero-page for reads */
- if (!(flags & FAULT_FLAG_WRITE)) {
---- a/mm/mmap.c
-+++ b/mm/mmap.c
-@@ -1647,7 +1647,8 @@ out:
- * update accounting. This is shared with both the
- * grow-up and grow-down cases.
- */
--static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
-+static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow,
-+ unsigned long gap)
- {
- struct mm_struct *mm = vma->vm_mm;
- struct rlimit *rlim = current->signal->rlim;
-@@ -1660,7 +1661,7 @@ static int acct_stack_growth(struct vm_a
- /* Stack limit test */
- actual_size = size;
- if (size && (vma->vm_flags & (VM_GROWSUP | VM_GROWSDOWN)))
-- actual_size -= PAGE_SIZE;
-+ actual_size -= gap;
- if (actual_size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur))
- return -ENOMEM;
-
-@@ -1701,7 +1702,7 @@ static int acct_stack_growth(struct vm_a
- * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
- * vma is the last one with address > vma->vm_end. Have to extend vma.
- */
--int expand_upwards(struct vm_area_struct *vma, unsigned long address)
-+int expand_upwards(struct vm_area_struct *vma, unsigned long address, unsigned long gap)
- {
- int error;
-
-@@ -1720,14 +1721,7 @@ int expand_upwards(struct vm_area_struct
- * vma->vm_start/vm_end cannot change under us because the caller
- * is required to hold the mmap_sem in read mode. We need the
- * anon_vma lock to serialize against concurrent expand_stacks.
-- * Also guard against wrapping around to address 0.
- */
-- if (address < PAGE_ALIGN(address+4))
-- address = PAGE_ALIGN(address+4);
-- else {
-- vma_unlock_anon_vma(vma);
-- return -ENOMEM;
-- }
- error = 0;
-
- /* Somebody else might have raced and expanded it already */
-@@ -1739,7 +1733,7 @@ int expand_upwards(struct vm_area_struct
-
- error = -ENOMEM;
- if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
-- error = acct_stack_growth(vma, size, grow);
-+ error = acct_stack_growth(vma, size, grow, gap);
- if (!error) {
- vma->vm_end = address;
- perf_event_mmap(vma);
-@@ -1756,7 +1750,7 @@ int expand_upwards(struct vm_area_struct
- * vma is the first one with address < vma->vm_start. Have to extend vma.
- */
- int expand_downwards(struct vm_area_struct *vma,
-- unsigned long address)
-+ unsigned long address, unsigned long gap)
- {
- int error;
-
-@@ -1789,7 +1783,7 @@ int expand_downwards(struct vm_area_stru
-
- error = -ENOMEM;
- if (grow <= vma->vm_pgoff) {
-- error = acct_stack_growth(vma, size, grow);
-+ error = acct_stack_growth(vma, size, grow, gap);
- if (!error) {
- vma->vm_start = address;
- vma->vm_pgoff -= grow;
-@@ -1802,29 +1796,72 @@ int expand_downwards(struct vm_area_stru
- return error;
- }
-
-+/* enforced gap between the expanding stack and other mappings. */
-+unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT;
-+
- /*
- * Note how expand_stack() refuses to expand the stack all the way to
- * abut the next virtual mapping, *unless* that mapping itself is also
-- * a stack mapping. We want to leave room for a guard page, after all
-+ * a stack mapping. We want to leave room for a guard area, after all
- * (the guard page itself is not added here, that is done by the
- * actual page faulting logic)
-- *
-- * This matches the behavior of the guard page logic (see mm/memory.c:
-- * check_stack_guard_page()), which only allows the guard page to be
-- * removed under these circumstances.
- */
- #ifdef CONFIG_STACK_GROWSUP
-+unsigned long expandable_stack_area(struct vm_area_struct *vma,
-+ unsigned long address, unsigned long *gap)
-+{
-+ struct vm_area_struct *next = vma->vm_next;
-+ unsigned long guard_gap = stack_guard_gap;
-+ unsigned long guard_addr;
-+
-+ address = ALIGN(address, PAGE_SIZE);;
-+ if (!next)
-+ goto out;
-+
-+ if (next->vm_flags & VM_GROWSUP) {
-+ guard_gap = min(guard_gap, next->vm_start - address);
-+ goto out;
-+ }
-+
-+ if (next->vm_start - address < guard_gap)
-+ return -ENOMEM;
-+out:
-+ if (TASK_SIZE - address < guard_gap)
-+ guard_gap = TASK_SIZE - address;
-+ guard_addr = address + guard_gap;
-+ *gap = guard_gap;
-+
-+ return guard_addr;
-+}
-+
- int expand_stack(struct vm_area_struct *vma, unsigned long address)
- {
-+ unsigned long gap;
-+
-+ address = expandable_stack_area(vma, address, &gap);
-+ if (IS_ERR_VALUE(address))
-+ return -ENOMEM;
-+ return expand_upwards(vma, address, gap);
-+}
-+
-+int stack_guard_area(struct vm_area_struct *vma, unsigned long address)
-+{
- struct vm_area_struct *next;
-
-- address &= PAGE_MASK;
-+ if (!(vma->vm_flags & VM_GROWSUP))
-+ return 0;
-+
-+ /*
-+ * strictly speaking there is a guard gap between disjoint stacks
-+ * but the gap is not canonical (it might be smaller) and it is
-+ * reasonably safe to assume that we can ignore that gap for stack
-+ * POPULATE or /proc/<pid>[s]maps purposes
-+ */
- next = vma->vm_next;
-- if (next && next->vm_start == address + PAGE_SIZE) {
-- if (!(next->vm_flags & VM_GROWSUP))
-- return -ENOMEM;
-- }
-- return expand_upwards(vma, address);
-+ if (next && next->vm_flags & VM_GROWSUP)
-+ return 0;
-+
-+ return vma->vm_end - address <= stack_guard_gap;
- }
-
- struct vm_area_struct *
-@@ -1844,17 +1881,73 @@ find_extend_vma(struct mm_struct *mm, un
- return prev;
- }
- #else
-+unsigned long expandable_stack_area(struct vm_area_struct *vma,
-+ unsigned long address, unsigned long *gap)
-+{
-+ struct vm_area_struct *prev = vma->vm_prev;
-+ unsigned long guard_gap = stack_guard_gap;
-+ unsigned long guard_addr;
-+
-+ address &= PAGE_MASK;
-+ if (!prev)
-+ goto out;
-+
-+ /*
-+ * Is there a mapping abutting this one below?
-+ *
-+ * That's only ok if it's the same stack mapping
-+ * that has gotten split or there is sufficient gap
-+ * between mappings
-+ */
-+ if (prev->vm_flags & VM_GROWSDOWN) {
-+ guard_gap = min(guard_gap, address - prev->vm_end);
-+ goto out;
-+ }
-+
-+ if (address - prev->vm_end < guard_gap)
-+ return -ENOMEM;
-+
-+out:
-+ /* make sure we won't underflow */
-+ if (address < mmap_min_addr)
-+ return -ENOMEM;
-+ if (address - mmap_min_addr < guard_gap)
-+ guard_gap = address - mmap_min_addr;
-+
-+ guard_addr = address - guard_gap;
-+ *gap = guard_gap;
-+
-+ return guard_addr;
-+}
-+
- int expand_stack(struct vm_area_struct *vma, unsigned long address)
- {
-+ unsigned long gap;
-+
-+ address = expandable_stack_area(vma, address, &gap);
-+ if (IS_ERR_VALUE(address))
-+ return -ENOMEM;
-+ return expand_downwards(vma, address, gap);
-+}
-+
-+int stack_guard_area(struct vm_area_struct *vma, unsigned long address)
-+{
- struct vm_area_struct *prev;
-
-- address &= PAGE_MASK;
-+ if (!(vma->vm_flags & VM_GROWSDOWN))
-+ return 0;
-+
-+ /*
-+ * strictly speaking there is a guard gap between disjoint stacks
-+ * but the gap is not canonical (it might be smaller) and it is
-+ * reasonably safe to assume that we can ignore that gap for stack
-+ * POPULATE or /proc/<pid>[s]maps purposes
-+ */
- prev = vma->vm_prev;
-- if (prev && prev->vm_end == address) {
-- if (!(prev->vm_flags & VM_GROWSDOWN))
-- return -ENOMEM;
-- }
-- return expand_downwards(vma, address);
-+ if (prev && prev->vm_flags & VM_GROWSDOWN)
-+ return 0;
-+
-+ return address - vma->vm_start < stack_guard_gap;
- }
-
- struct vm_area_struct *
diff --git a/debian/patches/bugfix/all/mm-larger-stack-guard-gap-between-vmas.patch b/debian/patches/bugfix/all/mm-larger-stack-guard-gap-between-vmas.patch
new file mode 100644
index 0000000..f663826
--- /dev/null
+++ b/debian/patches/bugfix/all/mm-larger-stack-guard-gap-between-vmas.patch
@@ -0,0 +1,1512 @@
+From: Hugh Dickins <hughd at google.com>
+Date: Mon, 19 Jun 2017 20:32:47 +0200
+Subject: mm: larger stack guard gap, between vmas
+Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2017-1000364
+
+commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream.
+
+Stack guard page is a useful feature to reduce a risk of stack smashing
+into a different mapping. We have been using a single page gap which
+is sufficient to prevent having stack adjacent to a different mapping.
+But this seems to be insufficient in the light of the stack usage in
+userspace. E.g. glibc uses as large as 64kB alloca() in many commonly
+used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX]
+which is 256kB or stack strings with MAX_ARG_STRLEN.
+
+This will become especially dangerous for suid binaries and the default
+no limit for the stack size limit because those applications can be
+tricked to consume a large portion of the stack and a single glibc call
+could jump over the guard page. These attacks are not theoretical,
+unfortunatelly.
+
+Make those attacks less probable by increasing the stack guard gap
+to 1MB (on systems with 4k pages; but make it depend on the page size
+because systems with larger base pages might cap stack allocations in
+the PAGE_SIZE units) which should cover larger alloca() and VLA stack
+allocations. It is obviously not a full fix because the problem is
+somehow inherent, but it should reduce attack space a lot.
+
+One could argue that the gap size should be configurable from userspace,
+but that can be done later when somebody finds that the new 1MB is wrong
+for some special case applications. For now, add a kernel command line
+option (stack_guard_gap) to specify the stack gap size (in page units).
+
+Implementation wise, first delete all the old code for stack guard page:
+because although we could get away with accounting one extra page in a
+stack vma, accounting a larger gap can break userspace - case in point,
+a program run with "ulimit -S -v 20000" failed when the 1MB gap was
+counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK
+and strict non-overcommit mode.
+
+Instead of keeping gap inside the stack vma, maintain the stack guard
+gap as a gap between vmas: using vm_start_gap() in place of vm_start
+(or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few
+places which need to respect the gap - mainly arch_get_unmapped_area(),
+and and the vma tree's subtree_gap support for that.
+
+Original-patch-by: Oleg Nesterov <oleg at redhat.com>
+Original-patch-by: Michal Hocko <mhocko at suse.com>
+Signed-off-by: Hugh Dickins <hughd at google.com>
+---
+And here's my attempt at a backport to 3.2.89, at last.
+I know it builds and boots and runs on x86 64 and 32,
+but that's about all that I've tried.
+
+If you diff against yours (I preferred not to send that diff,
+because of the couple of rejects in yours against 3.2.89),
+you'll find most of the difference is just noise from where
+I used a variable, but you had not yet done so in yours.
+
+But there are those three missing files, and there are a few
+places where I have a little "if (prev) {" block at the head of
+the loop after find_vma_prev(): I think those loops start off
+wrongly without that.
+
+I notice now that you don't use find_vma_prev() in your generic
+(mm/mmap.c) arch_get_unmapped_area() and _topdown(): and now
+that I reflect on it, I think you're perfectly correct to keep
+those simple (especially given the inefficient implementation
+of find_vma_prev() in 3.2 - only later was it changed to make
+use of vm_prev), since both ia64 and parisc provide their own
+arch_get_unmapped_area() in this release, and neither use the
+_topdown().
+
+Whereas I spent much too much time on adapting those generics
+to vm_end_gap(), and pretty much gave up on the _topdown() -
+it grieved me to end up calling find_vma_prev() each time
+around the loop (where before it called find_vma() each time
+around the loop), there is definitely better use to be made
+of vm_prev there, but too hard to get right as I grew tired.
+
+So please at least take a look through the diff from yours, I
+think you'll find a few things to bring in, but a lot to ignore.
+
+Hugh
+
+[bwh: Fix more instances of vma->vm_start in sparc64 impl. of
+ arch_get_unmapped_area_topdown() and generic impl. of
+ hugetlb_get_unmapped_area()]
+
+--- a/Documentation/kernel-parameters.txt
++++ b/Documentation/kernel-parameters.txt
+@@ -2463,6 +2463,13 @@ bytes respectively. Such letter suffixes
+ spia_pedr=
+ spia_peddr=
+
++ stack_guard_gap= [MM]
++ override the default stack gap protection. The value
++ is in page units and it defines how many pages prior
++ to (for stacks growing down) resp. after (for stacks
++ growing up) the main stack are reserved for no other
++ mapping. Default value is 256 pages.
++
+ stacktrace [FTRACE]
+ Enabled the stack tracer on boot up.
+
+--- a/arch/alpha/kernel/osf_sys.c
++++ b/arch/alpha/kernel/osf_sys.c
+@@ -1147,7 +1147,7 @@ arch_get_unmapped_area_1(unsigned long a
+ /* At this point: (!vma || addr < vma->vm_end). */
+ if (limit - len < addr)
+ return -ENOMEM;
+- if (!vma || addr + len <= vma->vm_start)
++ if (!vma || addr + len <= vm_start_vma(vma))
+ return addr;
+ addr = vma->vm_end;
+ vma = vma->vm_next;
+--- a/arch/arm/mm/mmap.c
++++ b/arch/arm/mm/mmap.c
+@@ -69,7 +69,7 @@ arch_get_unmapped_area(struct file *filp
+ {
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+- unsigned long start_addr;
++ unsigned long start_addr, vm_start;
+ int do_align = 0;
+ int aliasing = cache_is_vipt_aliasing();
+
+@@ -101,7 +101,7 @@ arch_get_unmapped_area(struct file *filp
+
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)))
+ return addr;
+ }
+ if (len > mm->cached_hole_size) {
+@@ -131,15 +131,17 @@ full_search:
+ }
+ return -ENOMEM;
+ }
+- if (!vma || addr + len <= vma->vm_start) {
++ if (vma)
++ vm_start = vm_start_gap(vma);
++ if (!vma || addr + len <= vm_start) {
+ /*
+ * Remember the place where we stopped the search:
+ */
+ mm->free_area_cache = addr + len;
+ return addr;
+ }
+- if (addr + mm->cached_hole_size < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (addr + mm->cached_hole_size < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+ addr = vma->vm_end;
+ if (do_align)
+ addr = COLOUR_ALIGN(addr, pgoff);
+--- a/arch/frv/mm/elf-fdpic.c
++++ b/arch/frv/mm/elf-fdpic.c
+@@ -74,7 +74,7 @@ unsigned long arch_get_unmapped_area(str
+ addr = PAGE_ALIGN(addr);
+ vma = find_vma(current->mm, addr);
+ if (TASK_SIZE - len >= addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)))
+ goto success;
+ }
+
+@@ -89,7 +89,7 @@ unsigned long arch_get_unmapped_area(str
+ for (; vma; vma = vma->vm_next) {
+ if (addr > limit)
+ break;
+- if (addr + len <= vma->vm_start)
++ if (addr + len <= vm_start_gap(vma))
+ goto success;
+ addr = vma->vm_end;
+ }
+@@ -104,7 +104,7 @@ unsigned long arch_get_unmapped_area(str
+ for (; vma; vma = vma->vm_next) {
+ if (addr > limit)
+ break;
+- if (addr + len <= vma->vm_start)
++ if (addr + len <= vm_start_gap(vma))
+ goto success;
+ addr = vma->vm_end;
+ }
+--- a/arch/ia64/kernel/sys_ia64.c
++++ b/arch/ia64/kernel/sys_ia64.c
+@@ -27,7 +27,8 @@ arch_get_unmapped_area (struct file *fil
+ long map_shared = (flags & MAP_SHARED);
+ unsigned long start_addr, align_mask = PAGE_SIZE - 1;
+ struct mm_struct *mm = current->mm;
+- struct vm_area_struct *vma;
++ struct vm_area_struct *vma, *prev;
++ unsigned long prev_end;
+
+ if (len > RGN_MAP_LIMIT)
+ return -ENOMEM;
+@@ -58,7 +59,17 @@ arch_get_unmapped_area (struct file *fil
+ full_search:
+ start_addr = addr = (addr + align_mask) & ~align_mask;
+
+- for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
++ for (vma = find_vma_prev(mm, addr, &prev); ; prev = vma,
++ vma = vma->vm_next) {
++ if (prev) {
++ prev_end = vm_end_gap(prev);
++ if (addr < prev_end) {
++ addr = (prev_end + align_mask) & ~align_mask;
++ /* If vma already violates gap, forget it */
++ if (vma && addr > vma->vm_start)
++ addr = vma->vm_start;
++ }
++ }
+ /* At this point: (!vma || addr < vma->vm_end). */
+ if (TASK_SIZE - len < addr || RGN_MAP_LIMIT - len < REGION_OFFSET(addr)) {
+ if (start_addr != TASK_UNMAPPED_BASE) {
+@@ -68,12 +79,11 @@ arch_get_unmapped_area (struct file *fil
+ }
+ return -ENOMEM;
+ }
+- if (!vma || addr + len <= vma->vm_start) {
++ if (!vma || addr + len <= vm_start_gap(vma)) {
+ /* Remember the address where we stopped this search: */
+ mm->free_area_cache = addr + len;
+ return addr;
+ }
+- addr = (vma->vm_end + align_mask) & ~align_mask;
+ }
+ }
+
+--- a/arch/ia64/mm/hugetlbpage.c
++++ b/arch/ia64/mm/hugetlbpage.c
+@@ -171,9 +171,9 @@ unsigned long hugetlb_get_unmapped_area(
+ /* At this point: (!vmm || addr < vmm->vm_end). */
+ if (REGION_OFFSET(addr) + len > RGN_MAP_LIMIT)
+ return -ENOMEM;
+- if (!vmm || (addr + len) <= vmm->vm_start)
++ if (!vmm || (addr + len) <= vm_start_gap(vmm))
+ return addr;
+- addr = ALIGN(vmm->vm_end, HPAGE_SIZE);
++ addr = ALIGN(vm_end_gap(vmm), HPAGE_SIZE);
+ }
+ }
+
+--- a/arch/mips/mm/mmap.c
++++ b/arch/mips/mm/mmap.c
+@@ -70,6 +70,7 @@ static unsigned long arch_get_unmapped_a
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ unsigned long addr = addr0;
++ unsigned long vm_start;
+ int do_color_align;
+
+ if (unlikely(len > TASK_SIZE))
+@@ -103,7 +104,7 @@ static unsigned long arch_get_unmapped_a
+
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)))
+ return addr;
+ }
+
+@@ -118,7 +119,7 @@ static unsigned long arch_get_unmapped_a
+ /* At this point: (!vma || addr < vma->vm_end). */
+ if (TASK_SIZE - len < addr)
+ return -ENOMEM;
+- if (!vma || addr + len <= vma->vm_start)
++ if (!vma || addr + len <= vm_start_gap(vma))
+ return addr;
+ addr = vma->vm_end;
+ if (do_color_align)
+@@ -145,7 +146,7 @@ static unsigned long arch_get_unmapped_a
+ /* make sure it can fit in the remaining address space */
+ if (likely(addr > len)) {
+ vma = find_vma(mm, addr - len);
+- if (!vma || addr <= vma->vm_start) {
++ if (!vma || addr <= vm_start_gap(vma)) {
+ /* cache the address as a hint for next time */
+ return mm->free_area_cache = addr - len;
+ }
+@@ -165,20 +166,22 @@ static unsigned long arch_get_unmapped_a
+ * return with success:
+ */
+ vma = find_vma(mm, addr);
+- if (likely(!vma || addr + len <= vma->vm_start)) {
++ if (vma)
++ vm_start = vm_start_gap(vma);
++ if (likely(!vma || addr + len <= vm_start)) {
+ /* cache the address as a hint for next time */
+ return mm->free_area_cache = addr;
+ }
+
+ /* remember the largest hole we saw so far */
+- if (addr + mm->cached_hole_size < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (addr + mm->cached_hole_size < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+
+ /* try just below the current vma->vm_start */
+- addr = vma->vm_start - len;
++ addr = vm_start - len;
+ if (do_color_align)
+ addr = COLOUR_ALIGN_DOWN(addr, pgoff);
+- } while (likely(len < vma->vm_start));
++ } while (likely(len < vm_start));
+
+ bottomup:
+ /*
+--- a/arch/parisc/kernel/sys_parisc.c
++++ b/arch/parisc/kernel/sys_parisc.c
+@@ -35,17 +35,27 @@
+
+ static unsigned long get_unshared_area(unsigned long addr, unsigned long len)
+ {
+- struct vm_area_struct *vma;
++ struct vm_area_struct *vma, *prev;
++ unsigned long prev_end;
+
+ addr = PAGE_ALIGN(addr);
+
+- for (vma = find_vma(current->mm, addr); ; vma = vma->vm_next) {
++ for (vma = find_vma_prev(current->mm, addr, &prev); ; prev = vma,
++ vma = vma->vm_next) {
++ if (prev) {
++ prev_end = vm_end_gap(prev);
++ if (addr < prev_end) {
++ addr = prev_end;
++ /* If vma already violates gap, forget it */
++ if (vma && addr > vma->vm_start)
++ addr = vma->vm_start;
++ }
++ }
+ /* At this point: (!vma || addr < vma->vm_end). */
+ if (TASK_SIZE - len < addr)
+ return -ENOMEM;
+- if (!vma || addr + len <= vma->vm_start)
++ if (!vma || addr + len <= vm_start_gap(vma))
+ return addr;
+- addr = vma->vm_end;
+ }
+ }
+
+@@ -70,22 +80,32 @@ static int get_offset(struct address_spa
+ static unsigned long get_shared_area(struct address_space *mapping,
+ unsigned long addr, unsigned long len, unsigned long pgoff)
+ {
+- struct vm_area_struct *vma;
++ struct vm_area_struct *vma, *prev;
++ unsigned long prev_end;
+ int offset = mapping ? get_offset(mapping) : 0;
+
+ offset = (offset + (pgoff << PAGE_SHIFT)) & 0x3FF000;
+
+ addr = DCACHE_ALIGN(addr - offset) + offset;
+
+- for (vma = find_vma(current->mm, addr); ; vma = vma->vm_next) {
++ for (vma = find_vma_prev(current->mm, addr, &prev); ; prev = vma,
++ vma = vma->vm_next) {
++ if (prev) {
++ prev_end = vm_end_gap(prev);
++ if (addr < prev_end) {
++ addr = DCACHE_ALIGN(prev_end - offset) + offset;
++ if (addr < prev_end) /* handle wraparound */
++ return -ENOMEM;
++ /* If vma already violates gap, forget it */
++ if (vma && addr > vma->vm_start)
++ addr = vma->vm_start;
++ }
++ }
+ /* At this point: (!vma || addr < vma->vm_end). */
+ if (TASK_SIZE - len < addr)
+ return -ENOMEM;
+- if (!vma || addr + len <= vma->vm_start)
++ if (!vma || addr + len <= vm_start_gap(vma))
+ return addr;
+- addr = DCACHE_ALIGN(vma->vm_end - offset) + offset;
+- if (addr < vma->vm_end) /* handle wraparound */
+- return -ENOMEM;
+ }
+ }
+
+--- a/arch/powerpc/mm/slice.c
++++ b/arch/powerpc/mm/slice.c
+@@ -98,7 +98,7 @@ static int slice_area_is_free(struct mm_
+ if ((mm->task_size - len) < addr)
+ return 0;
+ vma = find_vma(mm, addr);
+- return (!vma || (addr + len) <= vma->vm_start);
++ return (!vma || (addr + len) <= vm_start_gap(vma));
+ }
+
+ static int slice_low_has_vma(struct mm_struct *mm, unsigned long slice)
+@@ -227,7 +227,7 @@ static unsigned long slice_find_area_bot
+ int psize, int use_cache)
+ {
+ struct vm_area_struct *vma;
+- unsigned long start_addr, addr;
++ unsigned long start_addr, addr, vm_start;
+ struct slice_mask mask;
+ int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
+
+@@ -256,7 +256,9 @@ full_search:
+ addr = _ALIGN_UP(addr + 1, 1ul << SLICE_HIGH_SHIFT);
+ continue;
+ }
+- if (!vma || addr + len <= vma->vm_start) {
++ if (vma)
++ vm_start = vm_start_gap(vma);
++ if (!vma || addr + len <= vm_start) {
+ /*
+ * Remember the place where we stopped the search:
+ */
+@@ -264,8 +266,8 @@ full_search:
+ mm->free_area_cache = addr + len;
+ return addr;
+ }
+- if (use_cache && (addr + mm->cached_hole_size) < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (use_cache && (addr + mm->cached_hole_size) < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+ addr = vma->vm_end;
+ }
+
+@@ -284,7 +286,7 @@ static unsigned long slice_find_area_top
+ int psize, int use_cache)
+ {
+ struct vm_area_struct *vma;
+- unsigned long addr;
++ unsigned long addr, vm_start;
+ struct slice_mask mask;
+ int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
+
+@@ -336,7 +338,9 @@ static unsigned long slice_find_area_top
+ * return with success:
+ */
+ vma = find_vma(mm, addr);
+- if (!vma || (addr + len) <= vma->vm_start) {
++ if (vma)
++ vm_start = vm_start_gap(vma);
++ if (!vma || (addr + len) <= vm_start) {
+ /* remember the address as a hint for next time */
+ if (use_cache)
+ mm->free_area_cache = addr;
+@@ -344,11 +348,11 @@ static unsigned long slice_find_area_top
+ }
+
+ /* remember the largest hole we saw so far */
+- if (use_cache && (addr + mm->cached_hole_size) < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (use_cache && (addr + mm->cached_hole_size) < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+
+ /* try just below the current vma->vm_start */
+- addr = vma->vm_start;
++ addr = vm_start;
+ }
+
+ /*
+--- a/arch/sh/mm/mmap.c
++++ b/arch/sh/mm/mmap.c
+@@ -47,7 +47,7 @@ unsigned long arch_get_unmapped_area(str
+ {
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+- unsigned long start_addr;
++ unsigned long start_addr, vm_start;
+ int do_colour_align;
+
+ if (flags & MAP_FIXED) {
+@@ -75,7 +75,7 @@ unsigned long arch_get_unmapped_area(str
+
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)))
+ return addr;
+ }
+
+@@ -106,15 +106,17 @@ full_search:
+ }
+ return -ENOMEM;
+ }
+- if (likely(!vma || addr + len <= vma->vm_start)) {
++ if (vma)
++ vm_start = vm_start_gap(vma);
++ if (likely(!vma || addr + len <= vm_start)) {
+ /*
+ * Remember the place where we stopped the search:
+ */
+ mm->free_area_cache = addr + len;
+ return addr;
+ }
+- if (addr + mm->cached_hole_size < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (addr + mm->cached_hole_size < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+
+ addr = vma->vm_end;
+ if (do_colour_align)
+@@ -130,6 +132,7 @@ arch_get_unmapped_area_topdown(struct fi
+ struct vm_area_struct *vma;
+ struct mm_struct *mm = current->mm;
+ unsigned long addr = addr0;
++ unsigned long vm_start;
+ int do_colour_align;
+
+ if (flags & MAP_FIXED) {
+@@ -158,7 +161,7 @@ arch_get_unmapped_area_topdown(struct fi
+
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)))
+ return addr;
+ }
+
+@@ -179,7 +182,7 @@ arch_get_unmapped_area_topdown(struct fi
+ /* make sure it can fit in the remaining address space */
+ if (likely(addr > len)) {
+ vma = find_vma(mm, addr-len);
+- if (!vma || addr <= vma->vm_start) {
++ if (!vma || addr <= vm_start_gap(vma)) {
+ /* remember the address as a hint for next time */
+ return (mm->free_area_cache = addr-len);
+ }
+@@ -199,20 +202,22 @@ arch_get_unmapped_area_topdown(struct fi
+ * return with success:
+ */
+ vma = find_vma(mm, addr);
+- if (likely(!vma || addr+len <= vma->vm_start)) {
++ if (vma)
++ vm_start = vm_start_gap(vma);
++ if (likely(!vma || addr + len <= vm_start)) {
+ /* remember the address as a hint for next time */
+ return (mm->free_area_cache = addr);
+ }
+
+ /* remember the largest hole we saw so far */
+- if (addr + mm->cached_hole_size < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (addr + mm->cached_hole_size < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+
+ /* try just below the current vma->vm_start */
+- addr = vma->vm_start-len;
++ addr = vm_start-len;
+ if (do_colour_align)
+ addr = COLOUR_ALIGN_DOWN(addr, pgoff);
+- } while (likely(len < vma->vm_start));
++ } while (likely(len < vm_start));
+
+ bottomup:
+ /*
+--- a/arch/sparc/kernel/sys_sparc_32.c
++++ b/arch/sparc/kernel/sys_sparc_32.c
+@@ -71,7 +71,7 @@ unsigned long arch_get_unmapped_area(str
+ }
+ if (TASK_SIZE - PAGE_SIZE - len < addr)
+ return -ENOMEM;
+- if (!vmm || addr + len <= vmm->vm_start)
++ if (!vmm || addr + len <= vm_start_gap(vmm))
+ return addr;
+ addr = vmm->vm_end;
+ if (flags & MAP_SHARED)
+--- a/arch/sparc/kernel/sys_sparc_64.c
++++ b/arch/sparc/kernel/sys_sparc_64.c
+@@ -117,7 +117,7 @@ unsigned long arch_get_unmapped_area(str
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct * vma;
+ unsigned long task_size = TASK_SIZE;
+- unsigned long start_addr;
++ unsigned long start_addr, vm_start;
+ int do_color_align;
+
+ if (flags & MAP_FIXED) {
+@@ -147,7 +147,7 @@ unsigned long arch_get_unmapped_area(str
+
+ vma = find_vma(mm, addr);
+ if (task_size - len >= addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)))
+ return addr;
+ }
+
+@@ -181,15 +181,17 @@ full_search:
+ }
+ return -ENOMEM;
+ }
+- if (likely(!vma || addr + len <= vma->vm_start)) {
++ if (vma)
++ vm_start = vm_start_gap(vma);
++ if (likely(!vma || addr + len <= vm_start)) {
+ /*
+ * Remember the place where we stopped the search:
+ */
+ mm->free_area_cache = addr + len;
+ return addr;
+ }
+- if (addr + mm->cached_hole_size < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (addr + mm->cached_hole_size < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+
+ addr = vma->vm_end;
+ if (do_color_align)
+@@ -205,7 +207,7 @@ arch_get_unmapped_area_topdown(struct fi
+ struct vm_area_struct *vma;
+ struct mm_struct *mm = current->mm;
+ unsigned long task_size = STACK_TOP32;
+- unsigned long addr = addr0;
++ unsigned long addr = addr0, vm_start;
+ int do_color_align;
+
+ /* This should only ever run for 32-bit processes. */
+@@ -237,7 +239,7 @@ arch_get_unmapped_area_topdown(struct fi
+
+ vma = find_vma(mm, addr);
+ if (task_size - len >= addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)))
+ return addr;
+ }
+
+@@ -258,7 +260,7 @@ arch_get_unmapped_area_topdown(struct fi
+ /* make sure it can fit in the remaining address space */
+ if (likely(addr > len)) {
+ vma = find_vma(mm, addr-len);
+- if (!vma || addr <= vma->vm_start) {
++ if (!vma || addr <= vm_start_gap(vma)) {
+ /* remember the address as a hint for next time */
+ return (mm->free_area_cache = addr-len);
+ }
+@@ -278,20 +280,22 @@ arch_get_unmapped_area_topdown(struct fi
+ * return with success:
+ */
+ vma = find_vma(mm, addr);
+- if (likely(!vma || addr+len <= vma->vm_start)) {
++ if (vma)
++ vm_start = vm_start_gap(vma);
++ if (likely(!vma || addr + len <= vm_start)) {
+ /* remember the address as a hint for next time */
+ return (mm->free_area_cache = addr);
+ }
+
+ /* remember the largest hole we saw so far */
+- if (addr + mm->cached_hole_size < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (addr + mm->cached_hole_size < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+
+ /* try just below the current vma->vm_start */
+- addr = vma->vm_start-len;
++ addr = vm_start - len;
+ if (do_color_align)
+ addr = COLOUR_ALIGN_DOWN(addr, pgoff);
+- } while (likely(len < vma->vm_start));
++ } while (likely(len < vm_start));
+
+ bottomup:
+ /*
+--- a/arch/sparc/mm/hugetlbpage.c
++++ b/arch/sparc/mm/hugetlbpage.c
+@@ -33,7 +33,7 @@ static unsigned long hugetlb_get_unmappe
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct * vma;
+ unsigned long task_size = TASK_SIZE;
+- unsigned long start_addr;
++ unsigned long start_addr, vm_start;
+
+ if (test_thread_flag(TIF_32BIT))
+ task_size = STACK_TOP32;
+@@ -67,15 +67,17 @@ full_search:
+ }
+ return -ENOMEM;
+ }
+- if (likely(!vma || addr + len <= vma->vm_start)) {
++ if (vma)
++ vm_start = vm_start_gap(vma);
++ if (likely(!vma || addr + len <= vm_start)) {
+ /*
+ * Remember the place where we stopped the search:
+ */
+ mm->free_area_cache = addr + len;
+ return addr;
+ }
+- if (addr + mm->cached_hole_size < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (addr + mm->cached_hole_size < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+
+ addr = ALIGN(vma->vm_end, HPAGE_SIZE);
+ }
+@@ -90,6 +92,7 @@ hugetlb_get_unmapped_area_topdown(struct
+ struct vm_area_struct *vma;
+ struct mm_struct *mm = current->mm;
+ unsigned long addr = addr0;
++ unsigned long vm_start;
+
+ /* This should only ever run for 32-bit processes. */
+ BUG_ON(!test_thread_flag(TIF_32BIT));
+@@ -106,7 +109,7 @@ hugetlb_get_unmapped_area_topdown(struct
+ /* make sure it can fit in the remaining address space */
+ if (likely(addr > len)) {
+ vma = find_vma(mm, addr-len);
+- if (!vma || addr <= vma->vm_start) {
++ if (!vma || addr <= vm_start_gap(vma)) {
+ /* remember the address as a hint for next time */
+ return (mm->free_area_cache = addr-len);
+ }
+@@ -124,18 +127,20 @@ hugetlb_get_unmapped_area_topdown(struct
+ * return with success:
+ */
+ vma = find_vma(mm, addr);
+- if (likely(!vma || addr+len <= vma->vm_start)) {
++ if (vma)
++ vm_start = vm_start_gap(vma);
++ if (likely(!vma || addr + len <= vm_start)) {
+ /* remember the address as a hint for next time */
+ return (mm->free_area_cache = addr);
+ }
+
+ /* remember the largest hole we saw so far */
+- if (addr + mm->cached_hole_size < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (addr + mm->cached_hole_size < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+
+ /* try just below the current vma->vm_start */
+- addr = (vma->vm_start-len) & HPAGE_MASK;
+- } while (likely(len < vma->vm_start));
++ addr = (vm_start - len) & HPAGE_MASK;
++ } while (likely(len < vm_start));
+
+ bottomup:
+ /*
+@@ -182,7 +187,7 @@ hugetlb_get_unmapped_area(struct file *f
+ addr = ALIGN(addr, HPAGE_SIZE);
+ vma = find_vma(mm, addr);
+ if (task_size - len >= addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)))
+ return addr;
+ }
+ if (mm->get_unmapped_area == arch_get_unmapped_area)
+--- a/arch/tile/mm/hugetlbpage.c
++++ b/arch/tile/mm/hugetlbpage.c
+@@ -159,7 +159,7 @@ static unsigned long hugetlb_get_unmappe
+ struct hstate *h = hstate_file(file);
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+- unsigned long start_addr;
++ unsigned long start_addr, vm_start;
+
+ if (len > mm->cached_hole_size) {
+ start_addr = mm->free_area_cache;
+@@ -185,12 +185,14 @@ full_search:
+ }
+ return -ENOMEM;
+ }
+- if (!vma || addr + len <= vma->vm_start) {
++ if (vma)
++ vm_start = vm_start_gap(vma);
++ if (!vma || addr + len <= vm_start) {
+ mm->free_area_cache = addr + len;
+ return addr;
+ }
+- if (addr + mm->cached_hole_size < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (addr + mm->cached_hole_size < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+ addr = ALIGN(vma->vm_end, huge_page_size(h));
+ }
+ }
+@@ -204,6 +206,7 @@ static unsigned long hugetlb_get_unmappe
+ struct vm_area_struct *vma, *prev_vma;
+ unsigned long base = mm->mmap_base, addr = addr0;
+ unsigned long largest_hole = mm->cached_hole_size;
++ unsigned long vm_start;
+ int first_time = 1;
+
+ /* don't allow allocations above current base */
+@@ -234,9 +237,10 @@ try_again:
+
+ /*
+ * new region fits between prev_vma->vm_end and
+- * vma->vm_start, use it:
++ * vm_start, use it:
+ */
+- if (addr + len <= vma->vm_start &&
++ vm_start = vm_start_gap(vma);
++ if (addr + len <= vm_start &&
+ (!prev_vma || (addr >= prev_vma->vm_end))) {
+ /* remember the address as a hint for next time */
+ mm->cached_hole_size = largest_hole;
+@@ -251,13 +255,13 @@ try_again:
+ }
+
+ /* remember the largest hole we saw so far */
+- if (addr + largest_hole < vma->vm_start)
+- largest_hole = vma->vm_start - addr;
++ if (addr + largest_hole < vm_start)
++ largest_hole = vm_start - addr;
+
+ /* try just below the current vma->vm_start */
+- addr = (vma->vm_start - len) & huge_page_mask(h);
++ addr = (vm_start - len) & huge_page_mask(h);
+
+- } while (len <= vma->vm_start);
++ } while (len <= vm_start);
+
+ fail:
+ /*
+@@ -312,7 +316,7 @@ unsigned long hugetlb_get_unmapped_area(
+ addr = ALIGN(addr, huge_page_size(h));
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)))
+ return addr;
+ }
+ if (current->mm->get_unmapped_area == arch_get_unmapped_area)
+--- a/arch/x86/kernel/sys_x86_64.c
++++ b/arch/x86/kernel/sys_x86_64.c
+@@ -126,7 +126,7 @@ arch_get_unmapped_area(struct file *filp
+ {
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+- unsigned long start_addr;
++ unsigned long start_addr, vm_start;
+ unsigned long begin, end;
+
+ if (flags & MAP_FIXED)
+@@ -141,7 +141,7 @@ arch_get_unmapped_area(struct file *filp
+ addr = PAGE_ALIGN(addr);
+ vma = find_vma(mm, addr);
+ if (end - len >= addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)))
+ return addr;
+ }
+ if (((flags & MAP_32BIT) || test_thread_flag(TIF_IA32))
+@@ -172,15 +172,17 @@ full_search:
+ }
+ return -ENOMEM;
+ }
+- if (!vma || addr + len <= vma->vm_start) {
++ if (vma)
++ vm_start = vm_start_gap(vma);
++ if (!vma || addr + len <= vm_start) {
+ /*
+ * Remember the place where we stopped the search:
+ */
+ mm->free_area_cache = addr + len;
+ return addr;
+ }
+- if (addr + mm->cached_hole_size < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (addr + mm->cached_hole_size < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+
+ addr = vma->vm_end;
+ addr = align_addr(addr, filp, 0);
+@@ -196,6 +198,7 @@ arch_get_unmapped_area_topdown(struct fi
+ struct vm_area_struct *vma;
+ struct mm_struct *mm = current->mm;
+ unsigned long addr = addr0;
++ unsigned long vm_start;
+
+ /* requested length too big for entire address space */
+ if (len > TASK_SIZE)
+@@ -213,7 +216,7 @@ arch_get_unmapped_area_topdown(struct fi
+ addr = PAGE_ALIGN(addr);
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)))
+ return addr;
+ }
+
+@@ -232,7 +235,7 @@ arch_get_unmapped_area_topdown(struct fi
+ ALIGN_TOPDOWN);
+
+ vma = find_vma(mm, tmp_addr);
+- if (!vma || tmp_addr + len <= vma->vm_start)
++ if (!vma || tmp_addr + len <= vm_start_gap(vma))
+ /* remember the address as a hint for next time */
+ return mm->free_area_cache = tmp_addr;
+ }
+@@ -251,17 +254,19 @@ arch_get_unmapped_area_topdown(struct fi
+ * return with success:
+ */
+ vma = find_vma(mm, addr);
+- if (!vma || addr+len <= vma->vm_start)
++ if (vma)
++ vm_start = vm_start_gap(vma);
++ if (!vma || addr + len <= vm_start)
+ /* remember the address as a hint for next time */
+ return mm->free_area_cache = addr;
+
+ /* remember the largest hole we saw so far */
+- if (addr + mm->cached_hole_size < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (addr + mm->cached_hole_size < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+
+ /* try just below the current vma->vm_start */
+- addr = vma->vm_start-len;
+- } while (len < vma->vm_start);
++ addr = vm_start - len;
++ } while (len < vm_start);
+
+ bottomup:
+ /*
+--- a/arch/x86/mm/hugetlbpage.c
++++ b/arch/x86/mm/hugetlbpage.c
+@@ -277,7 +277,7 @@ static unsigned long hugetlb_get_unmappe
+ struct hstate *h = hstate_file(file);
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+- unsigned long start_addr;
++ unsigned long start_addr, vm_start;
+
+ if (len > mm->cached_hole_size) {
+ start_addr = mm->free_area_cache;
+@@ -303,12 +303,14 @@ full_search:
+ }
+ return -ENOMEM;
+ }
+- if (!vma || addr + len <= vma->vm_start) {
++ if (vma)
++ vm_start = vm_start_gap(vma);
++ if (!vma || addr + len <= vm_start) {
+ mm->free_area_cache = addr + len;
+ return addr;
+ }
+- if (addr + mm->cached_hole_size < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (addr + mm->cached_hole_size < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+ addr = ALIGN(vma->vm_end, huge_page_size(h));
+ }
+ }
+@@ -322,6 +324,7 @@ static unsigned long hugetlb_get_unmappe
+ struct vm_area_struct *vma, *prev_vma;
+ unsigned long base = mm->mmap_base, addr = addr0;
+ unsigned long largest_hole = mm->cached_hole_size;
++ unsigned long vm_start;
+ int first_time = 1;
+
+ /* don't allow allocations above current base */
+@@ -351,7 +354,8 @@ try_again:
+ * new region fits between prev_vma->vm_end and
+ * vma->vm_start, use it:
+ */
+- if (addr + len <= vma->vm_start &&
++ vm_start = vm_start_gap(vma);
++ if (addr + len <= vm_start &&
+ (!prev_vma || (addr >= prev_vma->vm_end))) {
+ /* remember the address as a hint for next time */
+ mm->cached_hole_size = largest_hole;
+@@ -365,12 +369,12 @@ try_again:
+ }
+
+ /* remember the largest hole we saw so far */
+- if (addr + largest_hole < vma->vm_start)
+- largest_hole = vma->vm_start - addr;
++ if (addr + largest_hole < vm_start)
++ largest_hole = vm_start - addr;
+
+ /* try just below the current vma->vm_start */
+- addr = (vma->vm_start - len) & huge_page_mask(h);
+- } while (len <= vma->vm_start);
++ addr = (vm_start - len) & huge_page_mask(h);
++ } while (len <= vm_start);
+
+ fail:
+ /*
+@@ -426,7 +430,7 @@ hugetlb_get_unmapped_area(struct file *f
+ addr = ALIGN(addr, huge_page_size(h));
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)))
+ return addr;
+ }
+ if (mm->get_unmapped_area == arch_get_unmapped_area)
+--- a/fs/hugetlbfs/inode.c
++++ b/fs/hugetlbfs/inode.c
+@@ -150,7 +150,7 @@ hugetlb_get_unmapped_area(struct file *f
+ addr = ALIGN(addr, huge_page_size(h));
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)))
+ return addr;
+ }
+
+@@ -176,7 +176,7 @@ full_search:
+ return -ENOMEM;
+ }
+
+- if (!vma || addr + len <= vma->vm_start)
++ if (!vma || addr + len <= vm_start_gap(vma))
+ return addr;
+ addr = ALIGN(vma->vm_end, huge_page_size(h));
+ }
+--- a/fs/proc/task_mmu.c
++++ b/fs/proc/task_mmu.c
+@@ -230,11 +230,7 @@ static void show_map_vma(struct seq_file
+
+ /* We don't show the stack guard page in /proc/maps */
+ start = vma->vm_start;
+- if (stack_guard_page_start(vma, start))
+- start += PAGE_SIZE;
+ end = vma->vm_end;
+- if (stack_guard_page_end(vma, end))
+- end -= PAGE_SIZE;
+
+ seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
+ start,
+--- a/include/linux/mm.h
++++ b/include/linux/mm.h
+@@ -1015,34 +1015,6 @@ int set_page_dirty(struct page *page);
+ int set_page_dirty_lock(struct page *page);
+ int clear_page_dirty_for_io(struct page *page);
+
+-/* Is the vma a continuation of the stack vma above it? */
+-static inline int vma_growsdown(struct vm_area_struct *vma, unsigned long addr)
+-{
+- return vma && (vma->vm_end == addr) && (vma->vm_flags & VM_GROWSDOWN);
+-}
+-
+-static inline int stack_guard_page_start(struct vm_area_struct *vma,
+- unsigned long addr)
+-{
+- return (vma->vm_flags & VM_GROWSDOWN) &&
+- (vma->vm_start == addr) &&
+- !vma_growsdown(vma->vm_prev, addr);
+-}
+-
+-/* Is the vma a continuation of the stack vma below it? */
+-static inline int vma_growsup(struct vm_area_struct *vma, unsigned long addr)
+-{
+- return vma && (vma->vm_start == addr) && (vma->vm_flags & VM_GROWSUP);
+-}
+-
+-static inline int stack_guard_page_end(struct vm_area_struct *vma,
+- unsigned long addr)
+-{
+- return (vma->vm_flags & VM_GROWSUP) &&
+- (vma->vm_end == addr) &&
+- !vma_growsup(vma->vm_next, addr);
+-}
+-
+ extern unsigned long move_page_tables(struct vm_area_struct *vma,
+ unsigned long old_addr, struct vm_area_struct *new_vma,
+ unsigned long new_addr, unsigned long len);
+@@ -1462,6 +1434,7 @@ unsigned long ra_submit(struct file_ra_s
+ struct address_space *mapping,
+ struct file *filp);
+
++extern unsigned long stack_guard_gap;
+ /* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */
+ extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
+
+@@ -1490,6 +1463,30 @@ static inline struct vm_area_struct * fi
+ return vma;
+ }
+
++static inline unsigned long vm_start_gap(struct vm_area_struct *vma)
++{
++ unsigned long vm_start = vma->vm_start;
++
++ if (vma->vm_flags & VM_GROWSDOWN) {
++ vm_start -= stack_guard_gap;
++ if (vm_start > vma->vm_start)
++ vm_start = 0;
++ }
++ return vm_start;
++}
++
++static inline unsigned long vm_end_gap(struct vm_area_struct *vma)
++{
++ unsigned long vm_end = vma->vm_end;
++
++ if (vma->vm_flags & VM_GROWSUP) {
++ vm_end += stack_guard_gap;
++ if (vm_end < vma->vm_end)
++ vm_end = -PAGE_SIZE;
++ }
++ return vm_end;
++}
++
+ static inline unsigned long vma_pages(struct vm_area_struct *vma)
+ {
+ return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+--- a/mm/memory.c
++++ b/mm/memory.c
+@@ -1605,12 +1605,6 @@ no_page_table:
+ return page;
+ }
+
+-static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr)
+-{
+- return stack_guard_page_start(vma, addr) ||
+- stack_guard_page_end(vma, addr+PAGE_SIZE);
+-}
+-
+ /**
+ * __get_user_pages() - pin user pages in memory
+ * @tsk: task_struct of target task
+@@ -1761,11 +1755,6 @@ int __get_user_pages(struct task_struct
+ int ret;
+ unsigned int fault_flags = 0;
+
+- /* For mlock, just skip the stack guard page. */
+- if (foll_flags & FOLL_MLOCK) {
+- if (stack_guard_page(vma, start))
+- goto next_page;
+- }
+ if (foll_flags & FOLL_WRITE)
+ fault_flags |= FAULT_FLAG_WRITE;
+ if (nonblocking)
+@@ -3122,40 +3111,6 @@ out_release:
+ }
+
+ /*
+- * This is like a special single-page "expand_{down|up}wards()",
+- * except we must first make sure that 'address{-|+}PAGE_SIZE'
+- * doesn't hit another vma.
+- */
+-static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address)
+-{
+- address &= PAGE_MASK;
+- if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) {
+- struct vm_area_struct *prev = vma->vm_prev;
+-
+- /*
+- * Is there a mapping abutting this one below?
+- *
+- * That's only ok if it's the same stack mapping
+- * that has gotten split..
+- */
+- if (prev && prev->vm_end == address)
+- return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM;
+-
+- return expand_downwards(vma, address - PAGE_SIZE);
+- }
+- if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
+- struct vm_area_struct *next = vma->vm_next;
+-
+- /* As VM_GROWSDOWN but s/below/above/ */
+- if (next && next->vm_start == address + PAGE_SIZE)
+- return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM;
+-
+- return expand_upwards(vma, address + PAGE_SIZE);
+- }
+- return 0;
+-}
+-
+-/*
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
+@@ -3174,10 +3129,6 @@ static int do_anonymous_page(struct mm_s
+ if (vma->vm_flags & VM_SHARED)
+ return VM_FAULT_SIGBUS;
+
+- /* Check if we need to add a guard page to the stack */
+- if (check_stack_guard_page(vma, address) < 0)
+- return VM_FAULT_SIGSEGV;
+-
+ /* Use the zero-page for reads */
+ if (!(flags & FAULT_FLAG_WRITE)) {
+ entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),
+--- a/mm/mmap.c
++++ b/mm/mmap.c
+@@ -245,6 +245,7 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
+ unsigned long rlim, retval;
+ unsigned long newbrk, oldbrk;
+ struct mm_struct *mm = current->mm;
++ struct vm_area_struct *next;
+ unsigned long min_brk;
+
+ down_write(&mm->mmap_sem);
+@@ -289,7 +290,8 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
+ }
+
+ /* Check against existing mmap mappings. */
+- if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
++ next = find_vma(mm, oldbrk);
++ if (next && newbrk + PAGE_SIZE > vm_start_gap(next))
+ goto out;
+
+ /* Ok, looks good - let it rip. */
+@@ -1368,8 +1370,8 @@ arch_get_unmapped_area(struct file *filp
+ unsigned long len, unsigned long pgoff, unsigned long flags)
+ {
+ struct mm_struct *mm = current->mm;
+- struct vm_area_struct *vma;
+- unsigned long start_addr;
++ struct vm_area_struct *vma, *prev;
++ unsigned long start_addr, vm_start, prev_end;
+
+ if (len > TASK_SIZE - mmap_min_addr)
+ return -ENOMEM;
+@@ -1379,9 +1381,10 @@ arch_get_unmapped_area(struct file *filp
+
+ if (addr) {
+ addr = PAGE_ALIGN(addr);
+- vma = find_vma(mm, addr);
++ vma = find_vma_prev(mm, addr, &prev);
+ if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)) &&
++ (!prev || addr >= vm_end_gap(prev)))
+ return addr;
+ }
+ if (len > mm->cached_hole_size) {
+@@ -1392,7 +1395,17 @@ arch_get_unmapped_area(struct file *filp
+ }
+
+ full_search:
+- for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
++ for (vma = find_vma_prev(mm, addr, &prev); ; prev = vma,
++ vma = vma->vm_next) {
++ if (prev) {
++ prev_end = vm_end_gap(prev);
++ if (addr < prev_end) {
++ addr = prev_end;
++ /* If vma already violates gap, forget it */
++ if (vma && addr > vma->vm_start)
++ addr = vma->vm_start;
++ }
++ }
+ /* At this point: (!vma || addr < vma->vm_end). */
+ if (TASK_SIZE - len < addr) {
+ /*
+@@ -1407,16 +1420,16 @@ full_search:
+ }
+ return -ENOMEM;
+ }
+- if (!vma || addr + len <= vma->vm_start) {
++ vm_start = vma ? vm_start_gap(vma) : TASK_SIZE;
++ if (addr + len <= vm_start) {
+ /*
+ * Remember the place where we stopped the search:
+ */
+ mm->free_area_cache = addr + len;
+ return addr;
+ }
+- if (addr + mm->cached_hole_size < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
+- addr = vma->vm_end;
++ if (addr + mm->cached_hole_size < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+ }
+ }
+ #endif
+@@ -1442,9 +1455,10 @@ arch_get_unmapped_area_topdown(struct fi
+ const unsigned long len, const unsigned long pgoff,
+ const unsigned long flags)
+ {
+- struct vm_area_struct *vma;
++ struct vm_area_struct *vma, *prev;
+ struct mm_struct *mm = current->mm;
+ unsigned long addr = addr0;
++ unsigned long vm_start, prev_end;
+ unsigned long low_limit = max(PAGE_SIZE, mmap_min_addr);
+
+ /* requested length too big for entire address space */
+@@ -1457,9 +1471,10 @@ arch_get_unmapped_area_topdown(struct fi
+ /* requesting a specific address */
+ if (addr) {
+ addr = PAGE_ALIGN(addr);
+- vma = find_vma(mm, addr);
++ vma = find_vma_prev(mm, addr, &prev);
+ if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)) &&
++ (!prev || addr >= vm_end_gap(prev)))
+ return addr;
+ }
+
+@@ -1474,8 +1489,9 @@ arch_get_unmapped_area_topdown(struct fi
+
+ /* make sure it can fit in the remaining address space */
+ if (addr >= low_limit + len) {
+- vma = find_vma(mm, addr-len);
+- if (!vma || addr <= vma->vm_start)
++ vma = find_vma_prev(mm, addr-len, &prev);
++ if ((!vma || addr <= vm_start_gap(vma)) &&
++ (!prev || addr-len >= vm_end_gap(prev)))
+ /* remember the address as a hint for next time */
+ return (mm->free_area_cache = addr-len);
+ }
+@@ -1491,18 +1507,21 @@ arch_get_unmapped_area_topdown(struct fi
+ * else if new region fits below vma->vm_start,
+ * return with success:
+ */
+- vma = find_vma(mm, addr);
+- if (!vma || addr+len <= vma->vm_start)
++ vma = find_vma_prev(mm, addr, &prev);
++ vm_start = vma ? vm_start_gap(vma) : mm->mmap_base;
++ prev_end = prev ? vm_end_gap(prev) : low_limit;
++
++ if (addr + len <= vm_start && addr >= prev_end)
+ /* remember the address as a hint for next time */
+ return (mm->free_area_cache = addr);
+
+ /* remember the largest hole we saw so far */
+- if (addr + mm->cached_hole_size < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (addr + mm->cached_hole_size < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+
+ /* try just below the current vma->vm_start */
+- addr = vma->vm_start-len;
+- } while (vma->vm_start >= low_limit + len);
++ addr = vm_start - len;
++ } while (vm_start >= low_limit + len);
+
+ bottomup:
+ /*
+@@ -1647,21 +1666,19 @@ out:
+ * update accounting. This is shared with both the
+ * grow-up and grow-down cases.
+ */
+-static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
++static int acct_stack_growth(struct vm_area_struct *vma,
++ unsigned long size, unsigned long grow)
+ {
+ struct mm_struct *mm = vma->vm_mm;
+ struct rlimit *rlim = current->signal->rlim;
+- unsigned long new_start, actual_size;
++ unsigned long new_start;
+
+ /* address space limit tests */
+ if (!may_expand_vm(mm, grow))
+ return -ENOMEM;
+
+ /* Stack limit test */
+- actual_size = size;
+- if (size && (vma->vm_flags & (VM_GROWSUP | VM_GROWSDOWN)))
+- actual_size -= PAGE_SIZE;
+- if (actual_size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur))
++ if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur))
+ return -ENOMEM;
+
+ /* mlock limit tests */
+@@ -1703,32 +1720,40 @@ static int acct_stack_growth(struct vm_a
+ */
+ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
+ {
+- int error;
++ struct vm_area_struct *next;
++ unsigned long gap_addr;
++ int error = 0;
+
+ if (!(vma->vm_flags & VM_GROWSUP))
+ return -EFAULT;
+
+- /*
+- * We must make sure the anon_vma is allocated
+- * so that the anon_vma locking is not a noop.
+- */
++ /* Guard against wrapping around to address 0. */
++ address &= PAGE_MASK;
++ address += PAGE_SIZE;
++ if (!address)
++ return -ENOMEM;
++
++ /* Enforce stack_guard_gap */
++ gap_addr = address + stack_guard_gap;
++ if (gap_addr < address)
++ return -ENOMEM;
++ next = vma->vm_next;
++ if (next && next->vm_start < gap_addr) {
++ if (!(next->vm_flags & VM_GROWSUP))
++ return -ENOMEM;
++ /* Check that both stack segments have the same anon_vma? */
++ }
++
++ /* We must make sure the anon_vma is allocated. */
+ if (unlikely(anon_vma_prepare(vma)))
+ return -ENOMEM;
+- vma_lock_anon_vma(vma);
+
+ /*
+ * vma->vm_start/vm_end cannot change under us because the caller
+ * is required to hold the mmap_sem in read mode. We need the
+ * anon_vma lock to serialize against concurrent expand_stacks.
+- * Also guard against wrapping around to address 0.
+ */
+- if (address < PAGE_ALIGN(address+4))
+- address = PAGE_ALIGN(address+4);
+- else {
+- vma_unlock_anon_vma(vma);
+- return -ENOMEM;
+- }
+- error = 0;
++ vma_lock_anon_vma(vma);
+
+ /* Somebody else might have raced and expanded it already */
+ if (address > vma->vm_end) {
+@@ -1758,27 +1783,36 @@ int expand_upwards(struct vm_area_struct
+ int expand_downwards(struct vm_area_struct *vma,
+ unsigned long address)
+ {
++ struct vm_area_struct *prev;
++ unsigned long gap_addr;
+ int error;
+
+- /*
+- * We must make sure the anon_vma is allocated
+- * so that the anon_vma locking is not a noop.
+- */
+- if (unlikely(anon_vma_prepare(vma)))
+- return -ENOMEM;
+-
+ address &= PAGE_MASK;
+ error = security_file_mmap(NULL, 0, 0, 0, address, 1);
+ if (error)
+ return error;
+
+- vma_lock_anon_vma(vma);
++ /* Enforce stack_guard_gap */
++ gap_addr = address - stack_guard_gap;
++ if (gap_addr > address)
++ return -ENOMEM;
++ prev = vma->vm_prev;
++ if (prev && prev->vm_end > gap_addr) {
++ if (!(prev->vm_flags & VM_GROWSDOWN))
++ return -ENOMEM;
++ /* Check that both stack segments have the same anon_vma? */
++ }
++
++ /* We must make sure the anon_vma is allocated. */
++ if (unlikely(anon_vma_prepare(vma)))
++ return -ENOMEM;
+
+ /*
+ * vma->vm_start/vm_end cannot change under us because the caller
+ * is required to hold the mmap_sem in read mode. We need the
+ * anon_vma lock to serialize against concurrent expand_stacks.
+ */
++ vma_lock_anon_vma(vma);
+
+ /* Somebody else might have raced and expanded it already */
+ if (address < vma->vm_start) {
+@@ -1802,28 +1836,25 @@ int expand_downwards(struct vm_area_stru
+ return error;
+ }
+
+-/*
+- * Note how expand_stack() refuses to expand the stack all the way to
+- * abut the next virtual mapping, *unless* that mapping itself is also
+- * a stack mapping. We want to leave room for a guard page, after all
+- * (the guard page itself is not added here, that is done by the
+- * actual page faulting logic)
+- *
+- * This matches the behavior of the guard page logic (see mm/memory.c:
+- * check_stack_guard_page()), which only allows the guard page to be
+- * removed under these circumstances.
+- */
++/* enforced gap between the expanding stack and other mappings. */
++unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT;
++
++static int __init cmdline_parse_stack_guard_gap(char *p)
++{
++ unsigned long val;
++ char *endptr;
++
++ val = simple_strtoul(p, &endptr, 10);
++ if (!*endptr)
++ stack_guard_gap = val << PAGE_SHIFT;
++
++ return 0;
++}
++__setup("stack_guard_gap=", cmdline_parse_stack_guard_gap);
++
+ #ifdef CONFIG_STACK_GROWSUP
+ int expand_stack(struct vm_area_struct *vma, unsigned long address)
+ {
+- struct vm_area_struct *next;
+-
+- address &= PAGE_MASK;
+- next = vma->vm_next;
+- if (next && next->vm_start == address + PAGE_SIZE) {
+- if (!(next->vm_flags & VM_GROWSUP))
+- return -ENOMEM;
+- }
+ return expand_upwards(vma, address);
+ }
+
+@@ -1846,14 +1877,6 @@ find_extend_vma(struct mm_struct *mm, un
+ #else
+ int expand_stack(struct vm_area_struct *vma, unsigned long address)
+ {
+- struct vm_area_struct *prev;
+-
+- address &= PAGE_MASK;
+- prev = vma->vm_prev;
+- if (prev && prev->vm_end == address) {
+- if (!(prev->vm_flags & VM_GROWSDOWN))
+- return -ENOMEM;
+- }
+ return expand_downwards(vma, address);
+ }
+
diff --git a/debian/patches/bugfix/all/mm-proc-cap-the-stack-gap-for-unpopulated-growing-vm.patch b/debian/patches/bugfix/all/mm-proc-cap-the-stack-gap-for-unpopulated-growing-vm.patch
deleted file mode 100644
index 046eda2..0000000
--- a/debian/patches/bugfix/all/mm-proc-cap-the-stack-gap-for-unpopulated-growing-vm.patch
+++ /dev/null
@@ -1,45 +0,0 @@
-From: Michal Hocko <mhocko at suse.com>
-Date: Wed, 14 Jun 2017 08:17:15 +0200
-Subject: mm, proc: cap the stack gap for unpopulated growing vmas
-Bug-Debian: https://security-tracker.debian.org/tracker/CVE-2017-1000364
-
-Oleg has noticed that show_map_vma has been overly eager to cut the
-the vma range for growing VMAs. This wasn't a big deal with 4kB stack
-gap but now that the gap is much larger we can simply get a bogus VMA
-range in show_map_vma.
-To quote Oleg
-: On ppc PAGE_SIZE == 64K, so stack_guard_gap == 16M, the application does
-: mmap(..., length=4M, ... MAP_GROWSDOWN) and /proc/pid/maps happily reports
-:
-: 30001000000-30000400000 rw-p 00000000 00:00 0
-
-Let's cap the reported range and show an empty range for this peculiar
-case which is what we have been doing for a long time. Note that the
-range will expand as soon as the first page fault happens on this range.
-
-Reported-by: Jan Stancek <jstancek at redhat.com>
-Signed-off-by: Michal Hocko <mhocko at suse.com>
----
- fs/proc/task_mmu.c | 4 ++--
- 1 file changed, 2 insertions(+), 2 deletions(-)
-
-diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
-index 02859e5a8cfc..d37ddc215907 100644
---- a/fs/proc/task_mmu.c
-+++ b/fs/proc/task_mmu.c
-@@ -234,13 +234,13 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, bool *has_gap)
- end = vma->vm_end;
- if (vma->vm_flags & VM_GROWSDOWN) {
- if (stack_guard_area(vma, start)) {
-- start += stack_guard_gap;
-+ start = min(end, start + stack_guard_gap);
- if (has_gap)
- *has_gap = true;
- }
- } else if (vma->vm_flags & VM_GROWSUP) {
- if (stack_guard_area(vma, end)) {
-- end -= stack_guard_gap;
-+ end = max(start, end - stack_guard_gap);
- if (has_gap)
- *has_gap = true;
- }
diff --git a/debian/patches/bugfix/arm/mm-larger-stack-guard-gap-between-vmas-arm-topdown.patch b/debian/patches/bugfix/arm/mm-larger-stack-guard-gap-between-vmas-arm-topdown.patch
new file mode 100644
index 0000000..8bdcf3f
--- /dev/null
+++ b/debian/patches/bugfix/arm/mm-larger-stack-guard-gap-between-vmas-arm-topdown.patch
@@ -0,0 +1,68 @@
+From: Ben Hutchings <ben at decadent.org.uk>
+Date: Mon, 26 Jun 2017 18:50:44 +0100
+Subject: mm: larger stack guard gap, between vmas - ARM topdown case
+Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2017-1000364
+Forwarded: not-needed
+
+Apply the stack gap in ARM implementation of
+arch_get_unmapped_area_topdown(). This is only needed in Debian's
+3.2 branch because we cherry-picked commit 7dbaa466780a "ARM: 7169/1:
+topdown mmap support" from 3.3.
+
+---
+--- a/arch/arm/mm/mmap.c
++++ b/arch/arm/mm/mmap.c
+@@ -155,7 +155,7 @@ arch_get_unmapped_area_topdown(struct fi
+ {
+ struct vm_area_struct *vma;
+ struct mm_struct *mm = current->mm;
+- unsigned long addr = addr0;
++ unsigned long addr = addr0, vm_start;
+ int do_align = 0;
+ int aliasing = cache_is_vipt_aliasing();
+
+@@ -185,7 +185,7 @@ arch_get_unmapped_area_topdown(struct fi
+ addr = PAGE_ALIGN(addr);
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr &&
+- (!vma || addr + len <= vma->vm_start))
++ (!vma || addr + len <= vm_start_gap(vma)))
+ return addr;
+ }
+
+@@ -205,7 +205,7 @@ arch_get_unmapped_area_topdown(struct fi
+ /* make sure it can fit in the remaining address space */
+ if (addr > len) {
+ vma = find_vma(mm, addr-len);
+- if (!vma || addr <= vma->vm_start)
++ if (!vma || addr <= vm_start_gap(vma))
+ /* remember the address as a hint for next time */
+ return (mm->free_area_cache = addr-len);
+ }
+@@ -224,19 +224,21 @@ arch_get_unmapped_area_topdown(struct fi
+ * return with success:
+ */
+ vma = find_vma(mm, addr);
+- if (!vma || addr+len <= vma->vm_start)
++ if (vma)
++ vm_start = vm_start_gap(vma);
++ if (!vma || addr + len <= vm_start)
+ /* remember the address as a hint for next time */
+ return (mm->free_area_cache = addr);
+
+ /* remember the largest hole we saw so far */
+- if (addr + mm->cached_hole_size < vma->vm_start)
+- mm->cached_hole_size = vma->vm_start - addr;
++ if (addr + mm->cached_hole_size < vm_start)
++ mm->cached_hole_size = vm_start - addr;
+
+ /* try just below the current vma->vm_start */
+- addr = vma->vm_start - len;
++ addr = vm_start - len;
+ if (do_align)
+ addr = COLOUR_ALIGN_DOWN(addr, pgoff);
+- } while (len < vma->vm_start);
++ } while (len < vm_start);
+
+ bottomup:
+ /*
diff --git a/debian/patches/series b/debian/patches/series
index 46a35ed..d1b8b0d 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -1111,10 +1111,8 @@ bugfix/all/ipv6-xfrm-handle-errors-reported-by-xfrm6_find_1stfr.patch
features/all/net-add-kfree_skb_list.patch
bugfix/all/ipv6-fix-leak-in-ipv6_gso_segment.patch
bugfix/all/mm-do-not-grow-the-stack-vma-just-because-of-an-over.patch
-bugfix/all/mm-enlarge-stack-guard-gap.patch
-bugfix/all/mm-allow-to-configure-stack-gap-size.patch
-bugfix/all/mm-proc-cap-the-stack-gap-for-unpopulated-growing-vm.patch
-bugfix/all/mm-do-not-collapse-stack-gap-into-thp.patch
+bugfix/all/mm-larger-stack-guard-gap-between-vmas.patch
+bugfix/arm/mm-larger-stack-guard-gap-between-vmas-arm-topdown.patch
# ABI maintenance
debian/perf-hide-abi-change-in-3.2.30.patch
--
Alioth's /usr/local/bin/git-commit-notice on /srv/git.debian.org/git/kernel/linux.git
More information about the Kernel-svn-changes
mailing list