[linux] 01/03: ipv6: Prevent overrun when parsing v6 header options (CVE-2017-9074)
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Thu Jun 1 06:23:59 UTC 2017
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carnil pushed a commit to branch sid
in repository linux.
commit 35c1e8ae8da3a2112c548febed03937d9806186f
Author: Salvatore Bonaccorso <carnil at debian.org>
Date: Thu Jun 1 08:04:17 2017 +0200
ipv6: Prevent overrun when parsing v6 header options (CVE-2017-9074)
---
debian/changelog | 1 +
...nt-overrun-when-parsing-v6-header-options.patch | 232 +++++++++++++++++++++
debian/patches/series | 1 +
3 files changed, 234 insertions(+)
diff --git a/debian/changelog b/debian/changelog
index 9934383..ffd5052 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -413,6 +413,7 @@ linux (4.9.30-1) UNRELEASED; urgency=medium
* tracing: Use strlcpy() instead of strcpy() in __trace_find_cmdline()
(CVE-2017-0605)
* dccp/tcp: do not inherit mc_list from parent (CVE-2017-8890)
+ * ipv6: Prevent overrun when parsing v6 header options (CVE-2017-9074)
-- Ben Hutchings <ben at decadent.org.uk> Mon, 08 May 2017 21:11:08 +0200
diff --git a/debian/patches/bugfix/all/ipv6-prevent-overrun-when-parsing-v6-header-options.patch b/debian/patches/bugfix/all/ipv6-prevent-overrun-when-parsing-v6-header-options.patch
new file mode 100644
index 0000000..ef53e81
--- /dev/null
+++ b/debian/patches/bugfix/all/ipv6-prevent-overrun-when-parsing-v6-header-options.patch
@@ -0,0 +1,232 @@
+From: Craig Gallek <kraig at google.com>
+Date: Tue, 16 May 2017 14:36:23 -0400
+Subject: ipv6: Prevent overrun when parsing v6 header options
+Origin: https://git.kernel.org/linus/2423496af35d94a87156b063ea5cedffc10a70a1
+Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2017-9074
+
+The KASAN warning repoted below was discovered with a syzkaller
+program. The reproducer is basically:
+ int s = socket(AF_INET6, SOCK_RAW, NEXTHDR_HOP);
+ send(s, &one_byte_of_data, 1, MSG_MORE);
+ send(s, &more_than_mtu_bytes_data, 2000, 0);
+
+The socket() call sets the nexthdr field of the v6 header to
+NEXTHDR_HOP, the first send call primes the payload with a non zero
+byte of data, and the second send call triggers the fragmentation path.
+
+The fragmentation code tries to parse the header options in order
+to figure out where to insert the fragment option. Since nexthdr points
+to an invalid option, the calculation of the size of the network header
+can made to be much larger than the linear section of the skb and data
+is read outside of it.
+
+This fix makes ip6_find_1stfrag return an error if it detects
+running out-of-bounds.
+
+[ 42.361487] ==================================================================
+[ 42.364412] BUG: KASAN: slab-out-of-bounds in ip6_fragment+0x11c8/0x3730
+[ 42.365471] Read of size 840 at addr ffff88000969e798 by task ip6_fragment-oo/3789
+[ 42.366469]
+[ 42.366696] CPU: 1 PID: 3789 Comm: ip6_fragment-oo Not tainted 4.11.0+ #41
+[ 42.367628] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.1-1ubuntu1 04/01/2014
+[ 42.368824] Call Trace:
+[ 42.369183] dump_stack+0xb3/0x10b
+[ 42.369664] print_address_description+0x73/0x290
+[ 42.370325] kasan_report+0x252/0x370
+[ 42.370839] ? ip6_fragment+0x11c8/0x3730
+[ 42.371396] check_memory_region+0x13c/0x1a0
+[ 42.371978] memcpy+0x23/0x50
+[ 42.372395] ip6_fragment+0x11c8/0x3730
+[ 42.372920] ? nf_ct_expect_unregister_notifier+0x110/0x110
+[ 42.373681] ? ip6_copy_metadata+0x7f0/0x7f0
+[ 42.374263] ? ip6_forward+0x2e30/0x2e30
+[ 42.374803] ip6_finish_output+0x584/0x990
+[ 42.375350] ip6_output+0x1b7/0x690
+[ 42.375836] ? ip6_finish_output+0x990/0x990
+[ 42.376411] ? ip6_fragment+0x3730/0x3730
+[ 42.376968] ip6_local_out+0x95/0x160
+[ 42.377471] ip6_send_skb+0xa1/0x330
+[ 42.377969] ip6_push_pending_frames+0xb3/0xe0
+[ 42.378589] rawv6_sendmsg+0x2051/0x2db0
+[ 42.379129] ? rawv6_bind+0x8b0/0x8b0
+[ 42.379633] ? _copy_from_user+0x84/0xe0
+[ 42.380193] ? debug_check_no_locks_freed+0x290/0x290
+[ 42.380878] ? ___sys_sendmsg+0x162/0x930
+[ 42.381427] ? rcu_read_lock_sched_held+0xa3/0x120
+[ 42.382074] ? sock_has_perm+0x1f6/0x290
+[ 42.382614] ? ___sys_sendmsg+0x167/0x930
+[ 42.383173] ? lock_downgrade+0x660/0x660
+[ 42.383727] inet_sendmsg+0x123/0x500
+[ 42.384226] ? inet_sendmsg+0x123/0x500
+[ 42.384748] ? inet_recvmsg+0x540/0x540
+[ 42.385263] sock_sendmsg+0xca/0x110
+[ 42.385758] SYSC_sendto+0x217/0x380
+[ 42.386249] ? SYSC_connect+0x310/0x310
+[ 42.386783] ? __might_fault+0x110/0x1d0
+[ 42.387324] ? lock_downgrade+0x660/0x660
+[ 42.387880] ? __fget_light+0xa1/0x1f0
+[ 42.388403] ? __fdget+0x18/0x20
+[ 42.388851] ? sock_common_setsockopt+0x95/0xd0
+[ 42.389472] ? SyS_setsockopt+0x17f/0x260
+[ 42.390021] ? entry_SYSCALL_64_fastpath+0x5/0xbe
+[ 42.390650] SyS_sendto+0x40/0x50
+[ 42.391103] entry_SYSCALL_64_fastpath+0x1f/0xbe
+[ 42.391731] RIP: 0033:0x7fbbb711e383
+[ 42.392217] RSP: 002b:00007ffff4d34f28 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
+[ 42.393235] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fbbb711e383
+[ 42.394195] RDX: 0000000000001000 RSI: 00007ffff4d34f60 RDI: 0000000000000003
+[ 42.395145] RBP: 0000000000000046 R08: 00007ffff4d34f40 R09: 0000000000000018
+[ 42.396056] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000400aad
+[ 42.396598] R13: 0000000000000066 R14: 00007ffff4d34ee0 R15: 00007fbbb717af00
+[ 42.397257]
+[ 42.397411] Allocated by task 3789:
+[ 42.397702] save_stack_trace+0x16/0x20
+[ 42.398005] save_stack+0x46/0xd0
+[ 42.398267] kasan_kmalloc+0xad/0xe0
+[ 42.398548] kasan_slab_alloc+0x12/0x20
+[ 42.398848] __kmalloc_node_track_caller+0xcb/0x380
+[ 42.399224] __kmalloc_reserve.isra.32+0x41/0xe0
+[ 42.399654] __alloc_skb+0xf8/0x580
+[ 42.400003] sock_wmalloc+0xab/0xf0
+[ 42.400346] __ip6_append_data.isra.41+0x2472/0x33d0
+[ 42.400813] ip6_append_data+0x1a8/0x2f0
+[ 42.401122] rawv6_sendmsg+0x11ee/0x2db0
+[ 42.401505] inet_sendmsg+0x123/0x500
+[ 42.401860] sock_sendmsg+0xca/0x110
+[ 42.402209] ___sys_sendmsg+0x7cb/0x930
+[ 42.402582] __sys_sendmsg+0xd9/0x190
+[ 42.402941] SyS_sendmsg+0x2d/0x50
+[ 42.403273] entry_SYSCALL_64_fastpath+0x1f/0xbe
+[ 42.403718]
+[ 42.403871] Freed by task 1794:
+[ 42.404146] save_stack_trace+0x16/0x20
+[ 42.404515] save_stack+0x46/0xd0
+[ 42.404827] kasan_slab_free+0x72/0xc0
+[ 42.405167] kfree+0xe8/0x2b0
+[ 42.405462] skb_free_head+0x74/0xb0
+[ 42.405806] skb_release_data+0x30e/0x3a0
+[ 42.406198] skb_release_all+0x4a/0x60
+[ 42.406563] consume_skb+0x113/0x2e0
+[ 42.406910] skb_free_datagram+0x1a/0xe0
+[ 42.407288] netlink_recvmsg+0x60d/0xe40
+[ 42.407667] sock_recvmsg+0xd7/0x110
+[ 42.408022] ___sys_recvmsg+0x25c/0x580
+[ 42.408395] __sys_recvmsg+0xd6/0x190
+[ 42.408753] SyS_recvmsg+0x2d/0x50
+[ 42.409086] entry_SYSCALL_64_fastpath+0x1f/0xbe
+[ 42.409513]
+[ 42.409665] The buggy address belongs to the object at ffff88000969e780
+[ 42.409665] which belongs to the cache kmalloc-512 of size 512
+[ 42.410846] The buggy address is located 24 bytes inside of
+[ 42.410846] 512-byte region [ffff88000969e780, ffff88000969e980)
+[ 42.411941] The buggy address belongs to the page:
+[ 42.412405] page:ffffea000025a780 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0
+[ 42.413298] flags: 0x100000000008100(slab|head)
+[ 42.413729] raw: 0100000000008100 0000000000000000 0000000000000000 00000001800c000c
+[ 42.414387] raw: ffffea00002a9500 0000000900000007 ffff88000c401280 0000000000000000
+[ 42.415074] page dumped because: kasan: bad access detected
+[ 42.415604]
+[ 42.415757] Memory state around the buggy address:
+[ 42.416222] ffff88000969e880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+[ 42.416904] ffff88000969e900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+[ 42.417591] >ffff88000969e980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
+[ 42.418273] ^
+[ 42.418588] ffff88000969ea00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
+[ 42.419273] ffff88000969ea80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
+[ 42.419882] ==================================================================
+
+Reported-by: Andrey Konovalov <andreyknvl at google.com>
+Signed-off-by: Craig Gallek <kraig at google.com>
+Signed-off-by: David S. Miller <davem at davemloft.net>
+---
+ net/ipv6/ip6_offload.c | 2 ++
+ net/ipv6/ip6_output.c | 4 ++++
+ net/ipv6/output_core.c | 14 ++++++++------
+ net/ipv6/udp_offload.c | 2 ++
+ 4 files changed, 16 insertions(+), 6 deletions(-)
+
+diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
+index 93e58a5..eab36ab 100644
+--- a/net/ipv6/ip6_offload.c
++++ b/net/ipv6/ip6_offload.c
+@@ -117,6 +117,8 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
+
+ if (udpfrag) {
+ unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
++ if (unfrag_ip6hlen < 0)
++ return ERR_PTR(unfrag_ip6hlen);
+ fptr = (struct frag_hdr *)((u8 *)ipv6h + unfrag_ip6hlen);
+ fptr->frag_off = htons(offset);
+ if (skb->next)
+diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
+index 58f6288..01deecd 100644
+--- a/net/ipv6/ip6_output.c
++++ b/net/ipv6/ip6_output.c
+@@ -598,6 +598,10 @@ int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
+ u8 *prevhdr, nexthdr = 0;
+
+ hlen = ip6_find_1stfragopt(skb, &prevhdr);
++ if (hlen < 0) {
++ err = hlen;
++ goto fail;
++ }
+ nexthdr = *prevhdr;
+
+ mtu = ip6_skb_dst_mtu(skb);
+diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c
+index cd42523..e9065b8 100644
+--- a/net/ipv6/output_core.c
++++ b/net/ipv6/output_core.c
+@@ -79,14 +79,13 @@ EXPORT_SYMBOL(ipv6_select_ident);
+ int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
+ {
+ u16 offset = sizeof(struct ipv6hdr);
+- struct ipv6_opt_hdr *exthdr =
+- (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
+ unsigned int packet_len = skb_tail_pointer(skb) -
+ skb_network_header(skb);
+ int found_rhdr = 0;
+ *nexthdr = &ipv6_hdr(skb)->nexthdr;
+
+- while (offset + 1 <= packet_len) {
++ while (offset <= packet_len) {
++ struct ipv6_opt_hdr *exthdr;
+
+ switch (**nexthdr) {
+
+@@ -107,13 +106,16 @@ int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
+ return offset;
+ }
+
+- offset += ipv6_optlen(exthdr);
+- *nexthdr = &exthdr->nexthdr;
++ if (offset + sizeof(struct ipv6_opt_hdr) > packet_len)
++ return -EINVAL;
++
+ exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
+ offset);
++ offset += ipv6_optlen(exthdr);
++ *nexthdr = &exthdr->nexthdr;
+ }
+
+- return offset;
++ return -EINVAL;
+ }
+ EXPORT_SYMBOL(ip6_find_1stfragopt);
+
+diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
+index ac858c4..b348cff 100644
+--- a/net/ipv6/udp_offload.c
++++ b/net/ipv6/udp_offload.c
+@@ -91,6 +91,8 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
+ * bytes to insert fragment header.
+ */
+ unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
++ if (unfrag_ip6hlen < 0)
++ return ERR_PTR(unfrag_ip6hlen);
+ nexthdr = *prevhdr;
+ *prevhdr = NEXTHDR_FRAGMENT;
+ unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +
+--
+2.1.4
+
diff --git a/debian/patches/series b/debian/patches/series
index 30fb4e6..f6d35db 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -106,6 +106,7 @@ debian/i386-686-pae-pci-set-pci-nobios-by-default.patch
debian/time-mark-timer_stats-as-broken.patch
bugfix/all/tracing-Use-strlcpy-instead-of-strcpy-in-__trace_fin.patch
bugfix/all/dccp-tcp-do-not-inherit-mc_list-from-parent.patch
+bugfix/all/ipv6-prevent-overrun-when-parsing-v6-header-options.patch
# Fix exported symbol versions
bugfix/ia64/revert-ia64-move-exports-to-definitions.patch
--
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