diff options
| author | Tadeusz Struk <tadeusz.struk@linaro.org> | 2022-03-10 15:25:38 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-28 08:46:44 +0200 |
| commit | 2774edd43ab1f1c0e81c353502ccd5df59bfaeae (patch) | |
| tree | 3df53f11e70afce56821da77e7aaa272719aa14a | |
| parent | 0aef7184630b599493a0dcad4eec6d42b3e68e91 (diff) | |
net: ipv6: fix skb_over_panic in __ip6_append_data
commit 5e34af4142ffe68f01c8a9acae83300f8911e20c upstream.
Syzbot found a kernel bug in the ipv6 stack:
LINK: https://syzkaller.appspot.com/bug?id=205d6f11d72329ab8d62a610c44c5e7e25415580
The reproducer triggers it by sending a crafted message via sendmmsg()
call, which triggers skb_over_panic, and crashes the kernel:
skbuff: skb_over_panic: text:ffffffff84647fb4 len:65575 put:65575
head:ffff888109ff0000 data:ffff888109ff0088 tail:0x100af end:0xfec0
dev:<NULL>
Update the check that prevents an invalid packet with MTU equal
to the fregment header size to eat up all the space for payload.
The reproducer can be found here:
LINK: https://syzkaller.appspot.com/text?tag=ReproC&x=1648c83fb00000
Reported-by: syzbot+e223cf47ec8ae183f2a0@syzkaller.appspotmail.com
Signed-off-by: Tadeusz Struk <tadeusz.struk@linaro.org>
Acked-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20220310232538.1044947-1-tadeusz.struk@linaro.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/ipv6/ip6_output.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 918a9520d1f1..360679600957 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1429,8 +1429,8 @@ static int __ip6_append_data(struct sock *sk, sizeof(struct frag_hdr) : 0) + rt->rt6i_nfheader_len; - if (mtu < fragheaderlen || - ((mtu - fragheaderlen) & ~7) + fragheaderlen < sizeof(struct frag_hdr)) + if (mtu <= fragheaderlen || + ((mtu - fragheaderlen) & ~7) + fragheaderlen <= sizeof(struct frag_hdr)) goto emsgsize; maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - |