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| author |   Jason Wang <jasowang@redhat.com> | 2012-05-30 21:18:10 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2012-05-31 18:22:45 -0400 |
| commit | cc9b17ad29ecaa20bfe426a8d4dbfb94b13ff1cc (patch) | |
| tree | dbf402b10788ab22d1d9d8c14866a910be497c29 /net/core | |
| parent | bql: Avoid possible inconsistent calculation. (diff) | |
| download | linux-dev-cc9b17ad29ecaa20bfe426a8d4dbfb94b13ff1cc.tar.xz linux-dev-cc9b17ad29ecaa20bfe426a8d4dbfb94b13ff1cc.zip | |
net: sock: validate data_len before allocating skb in sock_alloc_send_pskb()
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>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/sock.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/net/core/sock.c b/net/core/sock.c index 653f8c0aedc5..9e5b71fda6ec 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1592,6 +1592,11 @@ 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) @@ -1610,14 +1615,12 @@ 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++) { |