On Sun, 16 Jul 2023 21:06:52 +0200, Geraldo Nascimento wrote:
On Sun, Jul 16, 2023 at 03:07:23PM +0200, Takashi Iwai wrote:
On Sun, 16 Jul 2023 10:21:49 +0200, syzbot wrote:
Hello,
syzbot found the following issue on:
HEAD commit: 3f01e9fed845 Merge tag 'linux-watchdog-6.5-rc2' of git://w.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=14b07344a80000 kernel config: https://syzkaller.appspot.com/x/.config?x=75da4f0a455bdbd3 dashboard link: https://syzkaller.appspot.com/bug?extid=cf8e7fa4eeec59b3d485 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15877dc2a80000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12905004a80000
Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/441fb7ea58b8/disk-3f01e9fe.raw.... vmlinux: https://storage.googleapis.com/syzbot-assets/8fa7790ba0c3/vmlinux-3f01e9fe.x... kernel image: https://storage.googleapis.com/syzbot-assets/5e7a6471dadf/bzImage-3f01e9fe.x...
IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+cf8e7fa4eeec59b3d485@syzkaller.appspotmail.com
Warning: Permanently added '10.128.1.1' (ED25519) to the list of known hosts. executing program executing program BUG: memory leak unreferenced object 0xffff888100877000 (size 512): comm "syz-executor257", pid 5012, jiffies 4294941742 (age 12.790s) hex dump (first 32 bytes): 80 ff 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: [<ffffffff8154bf94>] kmalloc_trace+0x24/0x90 mm/slab_common.c:1076 [<ffffffff83d29e28>] kmalloc include/linux/slab.h:582 [inline] [<ffffffff83d29e28>] kzalloc include/linux/slab.h:703 [inline] [<ffffffff83d29e28>] snd_seq_create_port+0x78/0x300 sound/core/seq/seq_ports.c:135 [<ffffffff83d1f681>] snd_seq_ioctl_create_port+0xe1/0x2a0 sound/core/seq/seq_clientmgr.c:1324 [<ffffffff83d20e5e>] snd_seq_ioctl+0x13e/0x290 sound/core/seq/seq_clientmgr.c:2327 [<ffffffff81685173>] vfs_ioctl fs/ioctl.c:51 [inline] [<ffffffff81685173>] __do_sys_ioctl fs/ioctl.c:870 [inline] [<ffffffff81685173>] __se_sys_ioctl fs/ioctl.c:856 [inline] [<ffffffff81685173>] __x64_sys_ioctl+0x103/0x140 fs/ioctl.c:856 [<ffffffff84a77ff9>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<ffffffff84a77ff9>] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 [<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
BUG: memory leak unreferenced object 0xffff888106742c00 (size 512): comm "syz-executor257", pid 5013, jiffies 4294942276 (age 7.450s) hex dump (first 32 bytes): 80 ff 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: [<ffffffff8154bf94>] kmalloc_trace+0x24/0x90 mm/slab_common.c:1076 [<ffffffff83d29e28>] kmalloc include/linux/slab.h:582 [inline] [<ffffffff83d29e28>] kzalloc include/linux/slab.h:703 [inline] [<ffffffff83d29e28>] snd_seq_create_port+0x78/0x300 sound/core/seq/seq_ports.c:135 [<ffffffff83d1f681>] snd_seq_ioctl_create_port+0xe1/0x2a0 sound/core/seq/seq_clientmgr.c:1324 [<ffffffff83d20e5e>] snd_seq_ioctl+0x13e/0x290 sound/core/seq/seq_clientmgr.c:2327 [<ffffffff81685173>] vfs_ioctl fs/ioctl.c:51 [inline] [<ffffffff81685173>] __do_sys_ioctl fs/ioctl.c:870 [inline] [<ffffffff81685173>] __se_sys_ioctl fs/ioctl.c:856 [inline] [<ffffffff81685173>] __x64_sys_ioctl+0x103/0x140 fs/ioctl.c:856 [<ffffffff84a77ff9>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<ffffffff84a77ff9>] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 [<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
Likely a forgotten kfree() at the error path. The patch below should fix it.
Takashi
-- 8< -- From: Takashi Iwai tiwai@suse.de Subject: [PATCH] ALSA: seq: Fix memory leak at error path in snd_seq_create_port()
We forgot to release a newly allocated item at the error path in snd_seq_create_port(). This patch fixes it.
Thanks for the clarification and quick proposed resolution Takashi. As an ALSA novice these bots always stunt me, personally. I understand how helpful they are however, even if cryptic.
But shouldn't this be reported to security? It's always prone to bad stuff when we forget a kfree()
It's a bug that happened only on 6.5-rc1, so no need to bother too much with security issue fiasco for distros.
Takashi