[PATCH 3.13 010/187] iovec: make sure the caller actually wants anything in memcpy_fromiovecend

Kamal Mostafa
2014-09-15T23:21:47Z

From: Sasha Levin <sasha.levin@oracle.com>

[ 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@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
net/core/iovec.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/net/core/iovec.c b/net/core/iovec.c
index a9c46ba..26dc006 100644
--- a/net/core/iovec.c
+++ b/net/core/iovec.c
@@ -107,6 +107,10 @@ EXPORT_SYMBOL(memcpy_toiovecend);
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;
--
1.9.1