From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
David.Laight@aculab.com, kernel-hardening@lists.openwall.com,
davem@davemloft.net
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: [PATCH v5 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow
Date: Tue, 25 Apr 2017 17:52:11 +0200 [thread overview]
Message-ID: <20170425155215.4835-1-Jason@zx2c4.com> (raw)
In-Reply-To: <20170425.111717.1973239615715123840.davem@davemloft.net>
This is a defense-in-depth measure in response to bugs like
4d6fa57b4dab ("macsec: avoid heap overflow in skb_to_sgvec")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
This is a resend of v4 with all the other child commits along with it.
net/core/skbuff.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index f86bf69cfb8d..e75640006d78 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3489,7 +3489,9 @@ void __init skb_init(void)
* @len: Length of buffer space to be mapped
*
* Fill the specified scatter-gather list with mappings/pointers into a
- * region of the buffer space attached to a socket buffer.
+ * region of the buffer space attached to a socket buffer. Returns either
+ * the number of scatterlist items used, or -EMSGSIZE if the contents
+ * could not fit.
*/
static int
__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
@@ -3517,6 +3519,8 @@ __skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
if ((copy = end - offset) > 0) {
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+ if (elt && sg_is_last(&sg[elt - 1]))
+ return -EMSGSIZE;
if (copy > len)
copy = len;
@@ -3537,6 +3541,9 @@ __skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
end = start + frag_iter->len;
if ((copy = end - offset) > 0) {
+ if (elt && sg_is_last(&sg[elt - 1]))
+ return -EMSGSIZE;
+
if (copy > len)
copy = len;
elt += __skb_to_sgvec(frag_iter, sg+elt, offset - start,
@@ -3581,6 +3588,9 @@ int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int le
{
int nsg = __skb_to_sgvec(skb, sg, offset, len);
+ if (nsg <= 0)
+ return nsg;
+
sg_mark_end(&sg[nsg - 1]);
return nsg;
--
2.12.2
next prev parent reply other threads:[~2017-04-25 15:52 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-25 14:08 [PATCH 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow Jason A. Donenfeld
2017-04-25 14:08 ` [PATCH 2/5] ipsec: check return value of skb_to_sgvec always Jason A. Donenfeld
2017-04-25 14:08 ` [PATCH 3/5] rxrpc: " Jason A. Donenfeld
2017-04-25 14:08 ` [PATCH 4/5] macsec: " Jason A. Donenfeld
2017-04-25 14:08 ` [PATCH 5/5] virtio_net: " Jason A. Donenfeld
2017-04-25 14:16 ` [PATCH v2 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow Jason A. Donenfeld
2017-04-25 14:21 ` [PATCH v3 " Jason A. Donenfeld
2017-04-25 14:47 ` [PATCH " David Miller
2017-04-25 15:04 ` [PATCH v4 " Jason A. Donenfeld
2017-04-25 15:17 ` David Miller
2017-04-25 15:52 ` Jason A. Donenfeld [this message]
2017-04-25 15:52 ` [PATCH v5 2/5] ipsec: check return value of skb_to_sgvec always Jason A. Donenfeld
2017-04-25 15:52 ` [PATCH v5 3/5] rxrpc: " Jason A. Donenfeld
2017-04-25 15:52 ` [PATCH v5 4/5] macsec: " Jason A. Donenfeld
2017-04-25 15:52 ` [PATCH v5 5/5] virtio_net: " Jason A. Donenfeld
2017-04-25 18:47 ` [PATCH v6 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow Jason A. Donenfeld
2017-04-25 18:47 ` [PATCH v6 2/5] ipsec: check return value of skb_to_sgvec always Jason A. Donenfeld
2017-04-25 18:47 ` [PATCH v6 3/5] rxrpc: " Jason A. Donenfeld
2017-04-28 11:41 ` Sabrina Dubroca
2017-04-28 13:29 ` Jason A. Donenfeld
2017-04-25 18:47 ` [PATCH v6 4/5] macsec: " Jason A. Donenfeld
2017-04-25 18:47 ` [PATCH v6 5/5] virtio_net: " Jason A. Donenfeld
2017-04-27 9:21 ` [PATCH v6 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow Jason A. Donenfeld
2017-04-27 11:30 ` Sabrina Dubroca
2017-04-27 12:04 ` Jason A. Donenfeld
2017-04-27 14:54 ` David Laight
2017-04-27 15:54 ` David Miller
2017-04-28 16:18 ` Sabrina Dubroca
2017-04-28 22:47 ` Jason A. Donenfeld
2017-04-25 15:42 ` [PATCH " Sergei Shtylyov
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