On Tue, Jun 08, 2021 at 03:41:59PM +0300, Pavel Skripkin wrote:

On Tue, 08 Jun 2021 14:32:23 +0200 gregkh@linuxfoundation.org wrote:

...

This is a note to let you know that I've just added the patch titled

net: kcm: fix memory leak in kcm_sendmsg

to the 5.12-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: net-kcm-fix-memory-leak-in-kcm_sendmsg.patch and it can be found in the queue-5.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From c47cc304990a2813995b1a92bbc11d0bb9a19ea9 Mon Sep 17 00:00:00 2001 From: Pavel Skripkin paskripkin@gmail.com Date: Wed, 2 Jun 2021 22:26:40 +0300 Subject: net: kcm: fix memory leak in kcm_sendmsg

From: Pavel Skripkin paskripkin@gmail.com

commit c47cc304990a2813995b1a92bbc11d0bb9a19ea9 upstream.

Syzbot reported memory leak in kcm_sendmsg()[1]. The problem was in non-freed frag_list in case of error.

In the while loop:

if (head == skb) skb_shinfo(head)->frag_list = tskb; else skb->next = tskb;

frag_list filled with skbs, but nothing was freeing them.

backtrace: [<0000000094c02615>] __alloc_skb+0x5e/0x250 net/core/skbuff.c:198 [<00000000e5386cbd>] alloc_skb include/linux/skbuff.h:1083 [inline] [<00000000e5386cbd>] kcm_sendmsg+0x3b6/0xa50 net/kcm/kcmsock.c:967 [1] [<00000000f1613a8a>] sock_sendmsg_nosec net/socket.c:652 [inline] [<00000000f1613a8a>] sock_sendmsg+0x4c/0x60 net/socket.c:672

Reported-and-tested-by: syzbot+b039f5699bd82e1fb011@syzkaller.appspotmail.com Fixes: ab7ac4eb9832 ("kcm: Kernel Connection Multiplexor module") Cc: stable@vger.kernel.org Signed-off-by: Pavel Skripkin paskripkin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/kcm/kcmsock.c | 5 +++++ 1 file changed, 5 insertions(+)

Hi, Greg!

I CCed stable. This patch is broken and I've already sent a revert for this.

https://git.kernel.org/netdev/net/c/a47c397bb29f

Please, don't add this to stable trees. Im sorry

Now dropped from everywhere, thanks for letting me know.

greg k-h