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authorAlexander Potapenko <glider@google.com>2017-07-14 18:32:45 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-08-11 08:33:58 -0700
commit2e50111fedaff324f26d42c2cfa5504dd69279a8 (patch)
treeadf403b40af581c2038fbd3d6a1b14462a22bb6e
parent22d79d2d63d65be500ad6f73beb7b47d87646438 (diff)
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sctp: don't dereference ptr before leaving _sctp_walk_{params, errors}()
[ Upstream commit b1f5bfc27a19f214006b9b4db7b9126df2dfdf5a ] If the length field of the iterator (|pos.p| or |err|) is past the end of the chunk, we shouldn't access it. This bug has been detected by KMSAN. For the following pair of system calls: socket(PF_INET6, SOCK_STREAM, 0x84 /* IPPROTO_??? */) = 3 sendto(3, "A", 1, MSG_OOB, {sa_family=AF_INET6, sin6_port=htons(0), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = 1 the tool has reported a use of uninitialized memory: ================================================================== BUG: KMSAN: use of uninitialized memory in sctp_rcv+0x17b8/0x43b0 CPU: 1 PID: 2940 Comm: probe Not tainted 4.11.0-rc5+ #2926 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:16 dump_stack+0x172/0x1c0 lib/dump_stack.c:52 kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:927 __msan_warning_32+0x61/0xb0 mm/kmsan/kmsan_instr.c:469 __sctp_rcv_init_lookup net/sctp/input.c:1074 __sctp_rcv_lookup_harder net/sctp/input.c:1233 __sctp_rcv_lookup net/sctp/input.c:1255 sctp_rcv+0x17b8/0x43b0 net/sctp/input.c:170 sctp6_rcv+0x32/0x70 net/sctp/ipv6.c:984 ip6_input_finish+0x82f/0x1ee0 net/ipv6/ip6_input.c:279 NF_HOOK ./include/linux/netfilter.h:257 ip6_input+0x239/0x290 net/ipv6/ip6_input.c:322 dst_input ./include/net/dst.h:492 ip6_rcv_finish net/ipv6/ip6_input.c:69 NF_HOOK ./include/linux/netfilter.h:257 ipv6_rcv+0x1dbd/0x22e0 net/ipv6/ip6_input.c:203 __netif_receive_skb_core+0x2f6f/0x3a20 net/core/dev.c:4208 __netif_receive_skb net/core/dev.c:4246 process_backlog+0x667/0xba0 net/core/dev.c:4866 napi_poll net/core/dev.c:5268 net_rx_action+0xc95/0x1590 net/core/dev.c:5333 __do_softirq+0x485/0x942 kernel/softirq.c:284 do_softirq_own_stack+0x1c/0x30 arch/x86/entry/entry_64.S:902 </IRQ> do_softirq kernel/softirq.c:328 __local_bh_enable_ip+0x25b/0x290 kernel/softirq.c:181 local_bh_enable+0x37/0x40 ./include/linux/bottom_half.h:31 rcu_read_unlock_bh ./include/linux/rcupdate.h:931 ip6_finish_output2+0x19b2/0x1cf0 net/ipv6/ip6_output.c:124 ip6_finish_output+0x764/0x970 net/ipv6/ip6_output.c:149 NF_HOOK_COND ./include/linux/netfilter.h:246 ip6_output+0x456/0x520 net/ipv6/ip6_output.c:163 dst_output ./include/net/dst.h:486 NF_HOOK ./include/linux/netfilter.h:257 ip6_xmit+0x1841/0x1c00 net/ipv6/ip6_output.c:261 sctp_v6_xmit+0x3b7/0x470 net/sctp/ipv6.c:225 sctp_packet_transmit+0x38cb/0x3a20 net/sctp/output.c:632 sctp_outq_flush+0xeb3/0x46e0 net/sctp/outqueue.c:885 sctp_outq_uncork+0xb2/0xd0 net/sctp/outqueue.c:750 sctp_side_effects net/sctp/sm_sideeffect.c:1773 sctp_do_sm+0x6962/0x6ec0 net/sctp/sm_sideeffect.c:1147 sctp_primitive_ASSOCIATE+0x12c/0x160 net/sctp/primitive.c:88 sctp_sendmsg+0x43e5/0x4f90 net/sctp/socket.c:1954 inet_sendmsg+0x498/0x670 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:633 sock_sendmsg net/socket.c:643 SYSC_sendto+0x608/0x710 net/socket.c:1696 SyS_sendto+0x8a/0xb0 net/socket.c:1664 do_syscall_64+0xe6/0x130 arch/x86/entry/common.c:285 entry_SYSCALL64_slow_path+0x25/0x25 arch/x86/entry/entry_64.S:246 RIP: 0033:0x401133 RSP: 002b:00007fff6d99cd38 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00000000004002b0 RCX: 0000000000401133 RDX: 0000000000000001 RSI: 0000000000494088 RDI: 0000000000000003 RBP: 00007fff6d99cd90 R08: 00007fff6d99cd50 R09: 000000000000001c R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000004063d0 R14: 0000000000406460 R15: 0000000000000000 origin: save_stack_trace+0x37/0x40 arch/x86/kernel/stacktrace.c:59 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:302 kmsan_internal_poison_shadow+0xb1/0x1a0 mm/kmsan/kmsan.c:198 kmsan_poison_shadow+0x6d/0xc0 mm/kmsan/kmsan.c:211 slab_alloc_node mm/slub.c:2743 __kmalloc_node_track_caller+0x200/0x360 mm/slub.c:4351 __kmalloc_reserve net/core/skbuff.c:138 __alloc_skb+0x26b/0x840 net/core/skbuff.c:231 alloc_skb ./include/linux/skbuff.h:933 sctp_packet_transmit+0x31e/0x3a20 net/sctp/output.c:570 sctp_outq_flush+0xeb3/0x46e0 net/sctp/outqueue.c:885 sctp_outq_uncork+0xb2/0xd0 net/sctp/outqueue.c:750 sctp_side_effects net/sctp/sm_sideeffect.c:1773 sctp_do_sm+0x6962/0x6ec0 net/sctp/sm_sideeffect.c:1147 sctp_primitive_ASSOCIATE+0x12c/0x160 net/sctp/primitive.c:88 sctp_sendmsg+0x43e5/0x4f90 net/sctp/socket.c:1954 inet_sendmsg+0x498/0x670 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:633 sock_sendmsg net/socket.c:643 SYSC_sendto+0x608/0x710 net/socket.c:1696 SyS_sendto+0x8a/0xb0 net/socket.c:1664 do_syscall_64+0xe6/0x130 arch/x86/entry/common.c:285 return_from_SYSCALL_64+0x0/0x6a arch/x86/entry/entry_64.S:246 ================================================================== Signed-off-by: Alexander Potapenko <glider@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--include/net/sctp/sctp.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index 069582ee5d7f..257af3f88295 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -469,6 +469,8 @@ _sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
#define _sctp_walk_params(pos, chunk, end, member)\
for (pos.v = chunk->member;\
+ (pos.v + offsetof(struct sctp_paramhdr, length) + sizeof(pos.p->length) <\
+ (void *)chunk + end) &&\
pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
ntohs(pos.p->length) >= sizeof(sctp_paramhdr_t);\
pos.v += SCTP_PAD4(ntohs(pos.p->length)))
@@ -479,6 +481,8 @@ _sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
#define _sctp_walk_errors(err, chunk_hdr, end)\
for (err = (sctp_errhdr_t *)((void *)chunk_hdr + \
sizeof(sctp_chunkhdr_t));\
+ ((void *)err + offsetof(sctp_errhdr_t, length) + sizeof(err->length) <\
+ (void *)chunk_hdr + end) &&\
(void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
ntohs(err->length) >= sizeof(sctp_errhdr_t); \
err = (sctp_errhdr_t *)((void *)err + SCTP_PAD4(ntohs(err->length))))