From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Date: Tue, 01 Oct 2019 16:44:15 +0000 Subject: [PATCH AUTOSEL 4.14 21/29] ppp: Fix memory leak in ppp_write Message-Id: <20191001164423.16406-21-sashal@kernel.org> List-Id: References: <20191001164423.16406-1-sashal@kernel.org> In-Reply-To: <20191001164423.16406-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Takeshi Misawa , syzbot+d9c8bf24e56416d7ce2c@syzkaller.appspotmail.com, Guillaume Nault , "David S . Miller" , Sasha Levin , linux-ppp@vger.kernel.org, netdev@vger.kernel.org From: Takeshi Misawa [ Upstream commit 4c247de564f1ff614d11b3bb5313fb70d7b9598b ] When ppp is closing, __ppp_xmit_process() failed to enqueue skb and skb allocated in ppp_write() is leaked. syzbot reported : BUG: memory leak unreferenced object 0xffff88812a17bc00 (size 224): comm "syz-executor673", pid 6952, jiffies 4294942888 (age 13.040s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000d110fff9>] kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline] [<00000000d110fff9>] slab_post_alloc_hook mm/slab.h:522 [inline] [<00000000d110fff9>] slab_alloc_node mm/slab.c:3262 [inline] [<00000000d110fff9>] kmem_cache_alloc_node+0x163/0x2f0 mm/slab.c:3574 [<000000002d616113>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:197 [<000000000167fc45>] alloc_skb include/linux/skbuff.h:1055 [inline] [<000000000167fc45>] ppp_write+0x48/0x120 drivers/net/ppp/ppp_generic.c:502 [<000000009ab42c0b>] __vfs_write+0x43/0xa0 fs/read_write.c:494 [<00000000086b2e22>] vfs_write fs/read_write.c:558 [inline] [<00000000086b2e22>] vfs_write+0xee/0x210 fs/read_write.c:542 [<00000000a2b70ef9>] ksys_write+0x7c/0x130 fs/read_write.c:611 [<00000000ce5e0fdd>] __do_sys_write fs/read_write.c:623 [inline] [<00000000ce5e0fdd>] __se_sys_write fs/read_write.c:620 [inline] [<00000000ce5e0fdd>] __x64_sys_write+0x1e/0x30 fs/read_write.c:620 [<00000000d9d7b370>] do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:296 [<0000000006e6d506>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fix this by freeing skb, if ppp is closing. Fixes: 6d066734e9f0 ("ppp: avoid loop in xmit recursion detection code") Reported-and-tested-by: syzbot+d9c8bf24e56416d7ce2c@syzkaller.appspotmail.com Signed-off-by: Takeshi Misawa Reviewed-by: Guillaume Nault Tested-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ppp/ppp_generic.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c index 34b24d7e1e2f3..8faf4488340dd 100644 --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -1433,6 +1433,8 @@ static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb) netif_wake_queue(ppp->dev); else netif_stop_queue(ppp->dev); + } else { + kfree_skb(skb); } ppp_xmit_unlock(ppp); } -- 2.20.1