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 without check.
if a malicious user can change it between two fetches may cause security
problems or unexpected behaivor.
To fix this, we need to recheck it in the second fetch.
Signed-off-by: JingYi Hou <houjingyi...@gmail.com>
---
net/core/sock.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/core/sock.c b/net/core/sock.c
index 2b3701958486..577780c935ee 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1479,6 +1479,8 @@ int sock_getsockopt(struct socket *sock, int level, int
optname,
if (get_user(len, optlen))
return -EFAULT;
+ if (len < 0)
+ return -EINVAL;
sk_get_meminfo(sk, meminfo);
--
2.20.1
