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| author | John Hughes <john@calva.com> | 2010-04-07 21:29:25 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-04-07 21:29:25 -0700 |
| commit | f5eb917b861828da18dc28854308068c66d1449a (patch) | |
| tree | aa45d1a809abbe426b55dc89b8167e5a6609d418 /net/x25/x25_facilities.c | |
| parent | fd218cf9557b9bf7061365a8fe7020a56d3f767c (diff) | |
| download | linux-f5eb917b861828da18dc28854308068c66d1449a.tar.gz linux-f5eb917b861828da18dc28854308068c66d1449a.tar.bz2 linux-f5eb917b861828da18dc28854308068c66d1449a.zip | |
x25: Patch to fix bug 15678 - x25 accesses fields beyond end of packet.
Here is a patch to stop X.25 examining fields beyond the end of the packet.
For example, when a simple CALL ACCEPTED was received:
10 10 0f
x25_parse_facilities was attempting to decode the FACILITIES field, but this
packet contains no facilities field.
Signed-off-by: John Hughes <john@calva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/x25/x25_facilities.c')
| -rw-r--r-- | net/x25/x25_facilities.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/net/x25/x25_facilities.c b/net/x25/x25_facilities.c index a21f6646eb3a..a2765c6b1f1a 100644 --- a/net/x25/x25_facilities.c +++ b/net/x25/x25_facilities.c @@ -35,7 +35,7 @@ int x25_parse_facilities(struct sk_buff *skb, struct x25_facilities *facilities, struct x25_dte_facilities *dte_facs, unsigned long *vc_fac_mask) { unsigned char *p = skb->data; - unsigned int len = *p++; + unsigned int len; *vc_fac_mask = 0; @@ -50,6 +50,14 @@ int x25_parse_facilities(struct sk_buff *skb, struct x25_facilities *facilities, memset(dte_facs->called_ae, '\0', sizeof(dte_facs->called_ae)); memset(dte_facs->calling_ae, '\0', sizeof(dte_facs->calling_ae)); + if (skb->len < 1) + return 0; + + len = *p++; + + if (len >= skb->len) + return -1; + while (len > 0) { switch (*p & X25_FAC_CLASS_MASK) { case X25_FAC_CLASS_A: @@ -247,6 +255,8 @@ int x25_negotiate_facilities(struct sk_buff *skb, struct sock *sk, memcpy(new, ours, sizeof(*new)); len = x25_parse_facilities(skb, &theirs, dte, &x25->vc_facil_mask); + if (len < 0) + return len; /* * They want reverse charging, we won't accept it. |