| From | Greg Kroah-Hartman <> | Subject | [ 019/187] net: sock: validate data_len before allocating skb in sock_alloc_send_pskb() | Date | Thu, 12 Jul 2012 15:32:55 -0700 |
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From: Greg KH <gregkh@linuxfoundation.org>
3.4-stable review patch. If anyone has any objections, please let me know.
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From: Jason Wang <jasowang@redhat.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@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/core/sock.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/net/core/sock.c +++ b/net/core/sock.c @@ -1600,6 +1600,11 @@ struct sk_buff *sock_alloc_send_pskb(str 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) @@ -1618,14 +1623,12 @@ struct sk_buff *sock_alloc_send_pskb(str 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++) {
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