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authorMatthew Daley <mattjd@gmail.com>2011-10-14 18:45:04 +0000
committerDavid S. Miller <davem@davemloft.net>2011-10-17 19:31:39 -0400
commitcb101ed2c3c7c0224d16953fe77bfb9d6c2cb9df (patch)
tree3d266ac18673ebc85a99e4d10d8d381ff1ebd782 /net/x25/x25_facilities.c
parentc7fd0d48bde943e228e9c28ce971a22d6a1744c4 (diff)
x25: Handle undersized/fragmented skbs
There are multiple locations in the X.25 packet layer where a skb is assumed to be of at least a certain size and that all its data is currently available at skb->data. These assumptions are not checked, hence buffer overreads may occur. Use pskb_may_pull to check these minimal size assumptions and ensure that data is available at skb->data when necessary, as well as use skb_copy_bits where needed. Signed-off-by: Matthew Daley <mattjd@gmail.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Andrew Hendry <andrew.hendry@gmail.com> Cc: stable <stable@kernel.org> Acked-by: Andrew Hendry <andrew.hendry@gmail.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.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/net/x25/x25_facilities.c b/net/x25/x25_facilities.c
index f77e4e75f914..36384a1fa9f2 100644
--- a/net/x25/x25_facilities.c
+++ b/net/x25/x25_facilities.c
@@ -44,7 +44,7 @@
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 char *p;
unsigned int len;
*vc_fac_mask = 0;
@@ -60,14 +60,16 @@ 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)
+ if (!pskb_may_pull(skb, 1))
return 0;
- len = *p++;
+ len = skb->data[0];
- if (len >= skb->len)
+ if (!pskb_may_pull(skb, 1 + len))
return -1;
+ p = skb->data + 1;
+
while (len > 0) {
switch (*p & X25_FAC_CLASS_MASK) {
case X25_FAC_CLASS_A: