From cb101ed2c3c7c0224d16953fe77bfb9d6c2cb9df Mon Sep 17 00:00:00 2001 From: Matthew Daley Date: Fri, 14 Oct 2011 18:45:04 +0000 Subject: 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 Cc: Eric Dumazet Cc: Andrew Hendry Cc: stable Acked-by: Andrew Hendry Signed-off-by: David S. Miller --- net/x25/x25_facilities.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'net/x25/x25_facilities.c') 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: -- cgit v1.2.3