[ 29/48] net: sock: validate data_len before allocating skb in sock_alloc_send_pskb()
From: Ben Hutchings <hidden>
Date: 2012-07-09 14:43:32
Also in:
lkml
Subsystem:
networking [general], networking [sockets], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Kuniyuki Iwashima, Willem de Bruijn, Linus Torvalds
3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Wang <redacted> [ Upstream commit cc9b17ad29ecaa20bfe426a8d4dbfb94b13ff1cc ] We need to validate the number of pages consumed by data_len, otherwise frags array could be overflowed by userspace. So this patch validate data_len and return -EMSGSIZE when data_len may occupies more frags than MAX_SKB_FRAGS. Signed-off-by: Jason Wang <redacted> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Ben Hutchings <redacted> --- net/core/sock.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/core/sock.c b/net/core/sock.c
index b23f174..8d095b9 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c@@ -1497,6 +1497,11 @@ struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len, gfp_t gfp_mask; long timeo; int err; + int npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT; + + err = -EMSGSIZE; + if (npages > MAX_SKB_FRAGS) + goto failure; gfp_mask = sk->sk_allocation; if (gfp_mask & __GFP_WAIT)
@@ -1515,14 +1520,12 @@ struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len, if (atomic_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf) { skb = alloc_skb(header_len, gfp_mask); if (skb) { - int npages; int i; /* No pages, we're done... */ if (!data_len) break; - npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT; skb->truesize += data_len; skb_shinfo(skb)->nr_frags = npages; for (i = 0; i < npages; i++) {