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| author | andrew hendry <andrew.hendry@gmail.com> | 2011-02-07 03:08:15 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-02-08 00:41:38 +0300 |
| commit | 95c3043008ca8449feb96aba5481fe31c2ea750b (patch) | |
| tree | 1a80c238a56c1dc22a8b962f98ee1af363186e64 /net/x25/x25_in.c | |
| parent | 711c914688163dbe757c174788e20695088478e5 (diff) | |
| download | linux-95c3043008ca8449feb96aba5481fe31c2ea750b.tar.xz | |
x25: possible skb leak on bad facilities
Originally x25_parse_facilities returned
-1 for an error
0 meaning 0 length facilities
>0 the length of the facilities parsed.
5ef41308f94dc ("x25: Prevent crashing when parsing bad X.25 facilities") introduced more
error checking in x25_parse_facilities however used 0 to indicate bad parsing
a6331d6f9a429 ("memory corruption in X.25 facilities parsing") followed this further for
DTE facilities, again using 0 for bad parsing.
The meaning of 0 got confused in the callers.
If the facilities are messed up we can't determine where the data starts.
So patch makes all parsing errors return -1 and ensures callers close and don't use the skb further.
Reported-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Hendry <andrew.hendry@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/x25/x25_in.c')
| -rw-r--r-- | net/x25/x25_in.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/net/x25/x25_in.c b/net/x25/x25_in.c index f729f022be69..15de65f04719 100644 --- a/net/x25/x25_in.c +++ b/net/x25/x25_in.c @@ -91,10 +91,10 @@ static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametyp { struct x25_address source_addr, dest_addr; int len; + struct x25_sock *x25 = x25_sk(sk); switch (frametype) { case X25_CALL_ACCEPTED: { - struct x25_sock *x25 = x25_sk(sk); x25_stop_timer(sk); x25->condition = 0x00; @@ -113,14 +113,16 @@ static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametyp &dest_addr); if (len > 0) skb_pull(skb, len); + else if (len < 0) + goto out_clear; len = x25_parse_facilities(skb, &x25->facilities, &x25->dte_facilities, &x25->vc_facil_mask); if (len > 0) skb_pull(skb, len); - else - return -1; + else if (len < 0) + goto out_clear; /* * Copy any Call User Data. */ @@ -144,6 +146,12 @@ static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametyp } return 0; + +out_clear: + x25_write_internal(sk, X25_CLEAR_REQUEST); + x25->state = X25_STATE_2; + x25_start_t23timer(sk); + return 0; } /* |