[ 27/48] iovec: make sure the caller actually wants anything in

[Willy Tarreau]

2.6.32-longterm review patch.  If anyone has any objections, please let me know.

------------------
 memcpy_fromiovecend

From: Sasha Levin <sasha.levin@xxxxxxxxxx>

[ Upstream commit 06ebb06d49486676272a3c030bfeef4bd969a8e6 ]

Check for cases when the caller requests 0 bytes instead of running off
and dereferencing potentially invalid iovecs.

Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
 net/core/iovec.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/core/iovec.c b/net/core/iovec.c
index 3face24..5ca2fa8 100644
--- a/net/core/iovec.c
+++ b/net/core/iovec.c
@@ -153,6 +153,10 @@ int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len)
 int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov,
 			int offset, int len)
 {
+	/* No data? Done! */
+	if (len == 0)
+		return 0;
+
 	/* Skip over the finished iovecs */
 	while (offset >= iov->iov_len) {
 		offset -= iov->iov_len;
-- 
1.7.12.2.21.g234cd45.dirty



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