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Subject[PATCH] net: recvmsg: Unconditionally zero struct sockaddr_storage
Some protocols do not correctly wipe the contents of the on-stack
struct sockaddr_storage sent down into recvmsg() (e.g. SCTP), and leak
kernel stack contents to userspace. This wipes it unconditionally before
per-protocol handlers run.

Note that leaks like this are mitigated by building with

Reported-by: Alexander Potapenko <>
Cc: "David S. Miller" <>
Signed-off-by: Kees Cook <>
net/socket.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/net/socket.c b/net/socket.c
index c729625eb5d3..34183f4fbdf8 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2188,6 +2188,7 @@ static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
struct sockaddr __user *uaddr;
int __user *uaddr_len = COMPAT_NAMELEN(msg);

+ memset(&addr, 0, sizeof(addr));
msg_sys->msg_name = &addr;

if (MSG_CMSG_COMPAT & flags)

Kees Cook
Pixel Security

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