In sock_getsockopt(), 'optlen' is fetched the first time from userspace.
'len < 0' is then checked. Then in condition 'SO_MEMINFO', 'optlen' is
fetched the second time from userspace.
If change it between two fetches may cause security problems or unexpected
behaivor, and there is no reason to fetch it a second time.
To fix this, we need to remove the second fetch.
Signed-off-by: JingYi Hou <houjingyi...@gmail.com>
---
net/core/sock.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/net/core/sock.c b/net/core/sock.c
index 2b3701958486..932bcbf2d565 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1477,9 +1477,6 @@ int sock_getsockopt(struct socket *sock, int level, int
optname,
{
u32 meminfo[SK_MEMINFO_VARS];
- if (get_user(len, optlen))
- return -EFAULT;
-
sk_get_meminfo(sk, meminfo);
len = min_t(unsigned int, len, sizeof(meminfo));
--
2.20.1
