linux-kernel - [PATCH] Revert "ipv4: fix memory leaks in ip_cmsg

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Date:   Mon, 13 Sep 2021 12:04:42 +0800
From:   Yajun Deng <yajun.deng@...ux.dev>
To:     davem@...emloft.net, yoshfuji@...ux-ipv6.org, dsahern@...nel.org,
        kuba@...nel.org
Cc:     edumazet@...gle.com, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, Yajun Deng <yajun.deng@...ux.dev>
Subject: [PATCH] Revert "ipv4: fix memory leaks in ip_cmsg_send() callers"

This reverts commit 919483096bfe75dda338e98d56da91a263746a0a.

There is only when ip_options_get() return zero need to free.
It already called kfree() when return error.

Fixes: 919483096bfe ("ipv4: fix memory leaks in ip_cmsg_send() callers")
Signed-off-by: Yajun Deng <yajun.deng@...ux.dev>
---
 net/ipv4/ip_sockglue.c | 2 +-
 net/ipv4/ping.c        | 5 ++---
 net/ipv4/raw.c         | 5 ++---
 net/ipv4/udp.c         | 5 ++---
 4 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index b297bb28556e..7cef9987ab4a 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -279,7 +279,7 @@ int ip_cmsg_send(struct sock *sk, struct msghdr *msg, struct ipcm_cookie *ipc,
 		case IP_RETOPTS:
 			err = cmsg->cmsg_len - sizeof(struct cmsghdr);
 
-			/* Our caller is responsible for freeing ipc->opt */
+			/* Our caller is responsible for freeing ipc->opt when err = 0 */
 			err = ip_options_get(net, &ipc->opt,
 					     KERNEL_SOCKPTR(CMSG_DATA(cmsg)),
 					     err < 40 ? err : 40);
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 1e44a43acfe2..c588f9f2f46c 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -727,10 +727,9 @@ static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
 	if (msg->msg_controllen) {
 		err = ip_cmsg_send(sk, msg, &ipc, false);
-		if (unlikely(err)) {
-			kfree(ipc.opt);
+		if (unlikely(err))
 			return err;
-		}
+
 		if (ipc.opt)
 			free = 1;
 	}
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index bb446e60cf58..1c98063a3ae8 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -562,10 +562,9 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
 	if (msg->msg_controllen) {
 		err = ip_cmsg_send(sk, msg, &ipc, false);
-		if (unlikely(err)) {
-			kfree(ipc.opt);
+		if (unlikely(err))
 			goto out;
-		}
+
 		if (ipc.opt)
 			free = 1;
 	}
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 8851c9463b4b..d5f5981d7a43 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1122,10 +1122,9 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		if (err > 0)
 			err = ip_cmsg_send(sk, msg, &ipc,
 					   sk->sk_family == AF_INET6);
-		if (unlikely(err < 0)) {
-			kfree(ipc.opt);
+		if (unlikely(err < 0))
 			return err;
-		}
+
 		if (ipc.opt)
 			free = 1;
 		connected = 0;
-- 
2.32.0