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 <[email protected]> --- 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
