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authorAlexander Potapenko <glider@google.com>2017-05-03 17:06:58 +0200
committerDavid S. Miller <davem@davemloft.net>2017-05-04 11:02:46 -0400
commit86f4c90a1c5c1493f07f2d12c1079f5bf01936f2 (patch)
tree17c52c25229ac10b21762101bf88496494855d29 /net/ipv6/raw.c
parentnet/sched: remove redundant null check on head (diff)
downloadlinux-dev-86f4c90a1c5c1493f07f2d12c1079f5bf01936f2.tar.xz
linux-dev-86f4c90a1c5c1493f07f2d12c1079f5bf01936f2.zip
ipv4, ipv6: ensure raw socket message is big enough to hold an IP header
raw_send_hdrinc() and rawv6_send_hdrinc() expect that the buffer copied from the userspace contains the IPv4/IPv6 header, so if too few bytes are copied, parts of the header may remain uninitialized. This bug has been detected with KMSAN. For the record, the KMSAN report: ================================================================== BUG: KMSAN: use of unitialized memory in nf_ct_frag6_gather+0xf5a/0x44a0 inter: 0 CPU: 0 PID: 1036 Comm: probe Not tainted 4.11.0-rc5+ #2455 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 dump_stack+0x143/0x1b0 lib/dump_stack.c:52 kmsan_report+0x16b/0x1e0 mm/kmsan/kmsan.c:1078 __kmsan_warning_32+0x5c/0xa0 mm/kmsan/kmsan_instr.c:510 nf_ct_frag6_gather+0xf5a/0x44a0 net/ipv6/netfilter/nf_conntrack_reasm.c:577 ipv6_defrag+0x1d9/0x280 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:68 nf_hook_entry_hookfn ./include/linux/netfilter.h:102 nf_hook_slow+0x13f/0x3c0 net/netfilter/core.c:310 nf_hook ./include/linux/netfilter.h:212 NF_HOOK ./include/linux/netfilter.h:255 rawv6_send_hdrinc net/ipv6/raw.c:673 rawv6_sendmsg+0x2fcb/0x41a0 net/ipv6/raw.c:919 inet_sendmsg+0x3f8/0x6d0 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:633 sock_sendmsg net/socket.c:643 SYSC_sendto+0x6a5/0x7c0 net/socket.c:1696 SyS_sendto+0xbc/0xe0 net/socket.c:1664 do_syscall_64+0x72/0xa0 arch/x86/entry/common.c:285 entry_SYSCALL64_slow_path+0x25/0x25 arch/x86/entry/entry_64.S:246 RIP: 0033:0x436e03 RSP: 002b:00007ffce48baf38 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00000000004002b0 RCX: 0000000000436e03 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007ffce48baf90 R08: 00007ffce48baf50 R09: 000000000000001c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000401790 R14: 0000000000401820 R15: 0000000000000000 origin: 00000000d9400053 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:362 kmsan_internal_poison_shadow+0xb1/0x1a0 mm/kmsan/kmsan.c:257 kmsan_poison_shadow+0x6d/0xc0 mm/kmsan/kmsan.c:270 slab_alloc_node mm/slub.c:2735 __kmalloc_node_track_caller+0x1f4/0x390 mm/slub.c:4341 __kmalloc_reserve net/core/skbuff.c:138 __alloc_skb+0x2cd/0x740 net/core/skbuff.c:231 alloc_skb ./include/linux/skbuff.h:933 alloc_skb_with_frags+0x209/0xbc0 net/core/skbuff.c:4678 sock_alloc_send_pskb+0x9ff/0xe00 net/core/sock.c:1903 sock_alloc_send_skb+0xe4/0x100 net/core/sock.c:1920 rawv6_send_hdrinc net/ipv6/raw.c:638 rawv6_sendmsg+0x2918/0x41a0 net/ipv6/raw.c:919 inet_sendmsg+0x3f8/0x6d0 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:633 sock_sendmsg net/socket.c:643 SYSC_sendto+0x6a5/0x7c0 net/socket.c:1696 SyS_sendto+0xbc/0xe0 net/socket.c:1664 do_syscall_64+0x72/0xa0 arch/x86/entry/common.c:285 return_from_SYSCALL_64+0x0/0x6a arch/x86/entry/entry_64.S:246 ================================================================== , triggered by the following syscalls: socket(PF_INET6, SOCK_RAW, IPPROTO_RAW) = 3 sendto(3, NULL, 0, 0, {sa_family=AF_INET6, sin6_port=htons(0), inet_pton(AF_INET6, "ff00::", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = -1 EPERM A similar report is triggered in net/ipv4/raw.c if we use a PF_INET socket instead of a PF_INET6 one. Signed-off-by: Alexander Potapenko <glider@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/raw.c')
-rw-r--r--net/ipv6/raw.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 0da6a12b5472..1f992d9e261d 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -632,6 +632,8 @@ static int rawv6_send_hdrinc(struct sock *sk, struct msghdr *msg, int length,
ipv6_local_error(sk, EMSGSIZE, fl6, rt->dst.dev->mtu);
return -EMSGSIZE;
}
+ if (length < sizeof(struct ipv6hdr))
+ return -EINVAL;
if (flags&MSG_PROBE)
goto out;