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authorDavid S. Miller <davem@sunset.davemloft.net>2007-10-30 21:29:29 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2007-10-30 21:29:29 -0700
commit51c739d1f484b2562040a3e496dc8e1670d4e279 (patch)
tree87b12c2330f2951deb1a435367907d15a5d938c3 /net/core/skbuff.c
parent07afa040252eb41f91f46f8e538b434a63122999 (diff)
downloadlinux-51c739d1f484b2562040a3e496dc8e1670d4e279.tar.bz2
[NET]: Fix incorrect sg_mark_end() calls.
This fixes scatterlist corruptions added by commit 68e3f5dd4db62619fdbe520d36c9ebf62e672256 [CRYPTO] users: Fix up scatterlist conversion errors The issue is that the code calls sg_mark_end() which clobbers the sg_page() pointer of the final scatterlist entry. The first part fo the fix makes skb_to_sgvec() do __sg_mark_end(). After considering all skb_to_sgvec() call sites the most correct solution is to call __sg_mark_end() in skb_to_sgvec() since that is what all of the callers would end up doing anyways. I suspect this might have fixed some problems in virtio_net which is the sole non-crypto user of skb_to_sgvec(). Other similar sg_mark_end() cases were converted over to __sg_mark_end() as well. Arguably sg_mark_end() is a poorly named function because it doesn't just "mark", it clears out the page pointer as a side effect, which is what led to these bugs in the first place. The one remaining plain sg_mark_end() call is in scsi_alloc_sgtable() and arguably it could be converted to __sg_mark_end() if only so that we can delete this confusing interface from linux/scatterlist.h Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/skbuff.c')
-rw-r--r--net/core/skbuff.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 573e17240197..64b50ff7a413 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2028,8 +2028,8 @@ void __init skb_init(void)
* Fill the specified scatter-gather list with mappings/pointers into a
* region of the buffer space attached to a socket buffer.
*/
-int
-skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
+static int
+__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
{
int start = skb_headlen(skb);
int i, copy = start - offset;
@@ -2078,7 +2078,8 @@ skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
if ((copy = end - offset) > 0) {
if (copy > len)
copy = len;
- elt += skb_to_sgvec(list, sg+elt, offset - start, copy);
+ elt += __skb_to_sgvec(list, sg+elt, offset - start,
+ copy);
if ((len -= copy) == 0)
return elt;
offset += copy;
@@ -2090,6 +2091,15 @@ skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
return elt;
}
+int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
+{
+ int nsg = __skb_to_sgvec(skb, sg, offset, len);
+
+ __sg_mark_end(&sg[nsg - 1]);
+
+ return nsg;
+}
+
/**
* skb_cow_data - Check that a socket buffer's data buffers are writable
* @skb: The socket buffer to check.