[linux] 03/04: aacraid: Check size values after double-fetch from user (CVE-2016-6480)

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benh pushed a commit to branch wheezy-security
in repository linux.

commit 08df7d39a557029ce65beb1bdf7f00b34f986e01
Author: Ben Hutchings <ben at decadent.org.uk>
Date:   Tue Aug 30 13:02:41 2016 +0100

    aacraid: Check size values after double-fetch from user (CVE-2016-6480)
---
 debian/changelog                                   |  1 +
 ...ck-size-values-after-double-fetch-from-us.patch | 62 ++++++++++++++++++++++
 debian/patches/series                              |  1 +
 3 files changed, 64 insertions(+)

diff --git a/debian/changelog b/debian/changelog
index 0458d01..021dad9 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -12,6 +12,7 @@ linux (3.2.81-2) UNRELEASED; urgency=medium
     - trace: correct off by one while recording the trace-event
     - [x86] Fix an RT MCE crash
   * [arm*] oabi compat: add missing access checks (CVE-2016-3857)
+  * aacraid: Check size values after double-fetch from user (CVE-2016-6480)
 
  -- Ben Hutchings <ben at decadent.org.uk>  Fri, 17 Jun 2016 23:35:41 +0100
 
diff --git a/debian/patches/bugfix/all/aacraid-check-size-values-after-double-fetch-from-us.patch b/debian/patches/bugfix/all/aacraid-check-size-values-after-double-fetch-from-us.patch
new file mode 100644
index 0000000..d07f5fa
--- /dev/null
+++ b/debian/patches/bugfix/all/aacraid-check-size-values-after-double-fetch-from-us.patch
@@ -0,0 +1,62 @@
+From: Dave Carroll <david.carroll at microsemi.com>
+Date: Fri, 5 Aug 2016 13:44:10 -0600
+Subject: aacraid: Check size values after double-fetch from user
+Origin: https://git.kernel.org/linus/fa00c437eef8dc2e7b25f8cd868cfa405fcc2bb3
+
+In aacraid's ioctl_send_fib() we do two fetches from userspace, one the
+get the fib header's size and one for the fib itself. Later we use the
+size field from the second fetch to further process the fib. If for some
+reason the size from the second fetch is different than from the first
+fix, we may encounter an out-of- bounds access in aac_fib_send(). We
+also check the sender size to insure it is not out of bounds. This was
+reported in https://bugzilla.kernel.org/show_bug.cgi?id=116751 and was
+assigned CVE-2016-6480.
+
+Reported-by: Pengfei Wang <wpengfeinudt at gmail.com>
+Fixes: 7c00ffa31 '[SCSI] 2.6 aacraid: Variable FIB size (updated patch)'
+Cc: stable at vger.kernel.org
+Signed-off-by: Dave Carroll <david.carroll at microsemi.com>
+Reviewed-by: Johannes Thumshirn <jthumshirn at suse.de>
+Signed-off-by: Martin K. Petersen <martin.petersen at oracle.com>
+---
+ drivers/scsi/aacraid/commctrl.c | 13 +++++++++++--
+ 1 file changed, 11 insertions(+), 2 deletions(-)
+
+diff --git a/drivers/scsi/aacraid/commctrl.c b/drivers/scsi/aacraid/commctrl.c
+index b381b3718a98..5648b715fed9 100644
+--- a/drivers/scsi/aacraid/commctrl.c
++++ b/drivers/scsi/aacraid/commctrl.c
+@@ -63,7 +63,7 @@ static int ioctl_send_fib(struct aac_dev * dev, void __user *arg)
+ 	struct fib *fibptr;
+ 	struct hw_fib * hw_fib = (struct hw_fib *)0;
+ 	dma_addr_t hw_fib_pa = (dma_addr_t)0LL;
+-	unsigned size;
++	unsigned int size, osize;
+ 	int retval;
+ 
+ 	if (dev->in_reset) {
+@@ -87,7 +87,8 @@ static int ioctl_send_fib(struct aac_dev * dev, void __user *arg)
+ 	 *	will not overrun the buffer when we copy the memory. Return
+ 	 *	an error if we would.
+ 	 */
+-	size = le16_to_cpu(kfib->header.Size) + sizeof(struct aac_fibhdr);
++	osize = size = le16_to_cpu(kfib->header.Size) +
++		sizeof(struct aac_fibhdr);
+ 	if (size < le16_to_cpu(kfib->header.SenderSize))
+ 		size = le16_to_cpu(kfib->header.SenderSize);
+ 	if (size > dev->max_fib_size) {
+@@ -118,6 +119,14 @@ static int ioctl_send_fib(struct aac_dev * dev, void __user *arg)
+ 		goto cleanup;
+ 	}
+ 
++	/* Sanity check the second copy */
++	if ((osize != le16_to_cpu(kfib->header.Size) +
++		sizeof(struct aac_fibhdr))
++		|| (size < le16_to_cpu(kfib->header.SenderSize))) {
++		retval = -EINVAL;
++		goto cleanup;
++	}
++
+ 	if (kfib->header.Command == cpu_to_le16(TakeABreakPt)) {
+ 		aac_adapter_interrupt(dev);
+ 		/*
diff --git a/debian/patches/series b/debian/patches/series
index 54c2c92..a338bba 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -1119,6 +1119,7 @@ bugfix/all/hid-hiddev-validate-num_values-for-hidiocgusages-hid.patch
 bugfix/all/tcp-make-challenge-acks-less-predictable.patch
 bugfix/all/audit-fix-a-double-fetch-in-audit_log_single_execve_arg.patch
 bugfix/arm/arm-oabi-compat-add-missing-access-checks.patch
+bugfix/all/aacraid-check-size-values-after-double-fetch-from-us.patch
 
 # ABI maintenance
 debian/perf-hide-abi-change-in-3.2.30.patch

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