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Date: Mon, 09 Jul 2012 15:31:45 +0100 From: Ben Hutchings <ben@...adent.org.uk> To: linux-kernel@...r.kernel.org, stable@...r.kernel.org Cc: torvalds@...ux-foundation.org, akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk, Jason Wang <jasowang@...hat.com>, "David S. Miller" <davem@...emloft.net> Subject: [ 29/48] net: sock: validate data_len before allocating skb in sock_alloc_send_pskb() 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Wang <jasowang@...hat.com> [ 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 <jasowang@...hat.com> Signed-off-by: David S. Miller <davem@...emloft.net> Signed-off-by: Ben Hutchings <ben@...adent.org.uk> --- 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++) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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