| From foo@baz Tue Aug 8 16:51:58 PDT 2017 |
| From: Alexander Potapenko <glider@google.com> |
| Date: Fri, 14 Jul 2017 18:32:45 +0200 |
| Subject: sctp: don't dereference ptr before leaving _sctp_walk_{params, errors}() |
| |
| From: Alexander Potapenko <glider@google.com> |
| |
| |
| [ 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> |
| --- |
| include/net/sctp/sctp.h | 4 ++++ |
| 1 file changed, 4 insertions(+) |
| |
| --- a/include/net/sctp/sctp.h |
| +++ b/include/net/sctp/sctp.h |
| @@ -444,6 +444,8 @@ _sctp_walk_params((pos), (chunk), ntohs( |
| |
| #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 += WORD_ROUND(ntohs(pos.p->length))) |
| @@ -454,6 +456,8 @@ _sctp_walk_errors((err), (chunk_hdr), nt |
| #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 + WORD_ROUND(ntohs(err->length)))) |