3.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Alexander Potapenko <glider@xxxxxxxxxx>
[ Upstream commit 86f4c90a1c5c1493f07f2d12c1079f5bf01936f2 ]
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@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/raw.c | 3 +++
net/ipv6/raw.c | 2 ++
2 files changed, 5 insertions(+)
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -345,6 +345,9 @@ static int raw_send_hdrinc(struct sock *
rt->dst.dev->mtu);
return -EMSGSIZE;
}
+ if (length < sizeof(struct iphdr))
+ return -EINVAL;
+
if (flags&MSG_PROBE)
goto out;
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -624,6 +624,8 @@ static int rawv6_send_hdrinc(struct sock
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;