diff options
| author | Daniel Borkmann <dborkman@redhat.com> | 2013-12-30 23:40:50 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-02-15 19:20:10 +0000 |
| commit | 10cc99961394c0e62e0742d5459f4b347f540d30 (patch) | |
| tree | 4d61cd715b45da438c609415ee46c8b70711b3c4 /net | |
| parent | 31da359741b539fb236d5781b46ee7c5c6d8f14c (diff) | |
net: llc: fix use after free in llc_ui_recvmsg
[ Upstream commit 4d231b76eef6c4a6bd9c96769e191517765942cb ]
While commit 30a584d944fb fixes datagram interface in LLC, a use
after free bug has been introduced for SOCK_STREAM sockets that do
not make use of MSG_PEEK.
The flow is as follow ...
if (!(flags & MSG_PEEK)) {
...
sk_eat_skb(sk, skb, false);
...
}
...
if (used + offset < skb->len)
continue;
... where sk_eat_skb() calls __kfree_skb(). Therefore, cache
original length and work on skb_len to check partial reads.
Fixes: 30a584d944fb ("[LLX]: SOCK_DGRAM interface fixes")
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'net')
| -rw-r--r-- | net/llc/af_llc.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c index 99a60d545b2..f432d7b6d93 100644 --- a/net/llc/af_llc.c +++ b/net/llc/af_llc.c @@ -715,7 +715,7 @@ static int llc_ui_recvmsg(struct kiocb *iocb, struct socket *sock, struct llc_sock *llc = llc_sk(sk); size_t copied = 0; u32 peek_seq = 0; - u32 *seq; + u32 *seq, skb_len; unsigned long used; int target; /* Read at least this many bytes */ long timeo; @@ -813,6 +813,7 @@ static int llc_ui_recvmsg(struct kiocb *iocb, struct socket *sock, } continue; found_ok_skb: + skb_len = skb->len; /* Ok so how much can we use? */ used = skb->len - offset; if (len < used) @@ -843,7 +844,7 @@ static int llc_ui_recvmsg(struct kiocb *iocb, struct socket *sock, } /* Partial read */ - if (used + offset < skb->len) + if (used + offset < skb_len) continue; } while (len > 0); |