49 lines
1.5 KiB
Diff
49 lines
1.5 KiB
Diff
From: Jason Wang <jasowang@redhat.com>
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Date: Wed, 30 May 2012 21:18:10 +0000
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Subject: net: sock: validate data_len before allocating skb in
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sock_alloc_send_pskb()
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commit cc9b17ad29ecaa20bfe426a8d4dbfb94b13ff1cc upstream.
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We need to validate the number of pages consumed by data_len, otherwise frags
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array could be overflowed by userspace. So this patch validate data_len and
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return -EMSGSIZE when data_len may occupies more frags than MAX_SKB_FRAGS.
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Signed-off-by: Jason Wang <jasowang@redhat.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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net/core/sock.c | 7 +++++--
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1 file changed, 5 insertions(+), 2 deletions(-)
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diff --git a/net/core/sock.c b/net/core/sock.c
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index 653f8c0..9e5b71f 100644
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--- a/net/core/sock.c
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+++ b/net/core/sock.c
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@@ -1592,6 +1592,11 @@ struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
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gfp_t gfp_mask;
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long timeo;
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int err;
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+ int npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
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+
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+ err = -EMSGSIZE;
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+ if (npages > MAX_SKB_FRAGS)
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+ goto failure;
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gfp_mask = sk->sk_allocation;
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if (gfp_mask & __GFP_WAIT)
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@@ -1610,14 +1615,12 @@ struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
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if (atomic_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf) {
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skb = alloc_skb(header_len, gfp_mask);
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if (skb) {
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- int npages;
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int i;
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/* No pages, we're done... */
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if (!data_len)
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break;
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- npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
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skb->truesize += data_len;
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skb_shinfo(skb)->nr_frags = npages;
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for (i = 0; i < npages; i++) {
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