Re: [syzbot] memory leak in setup_mq_sysctls

Alexey Gladkov
2022-06-21T09:54:53Z

On Sun, Jun 19, 2022 at 11:52:25PM -0700, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 979086f5e006 Merge tag 'fs.fixes.v5.19-rc3' of git://git.k..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=1284331bf00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=c696a83383a77f81
> dashboard link: https://syzkaller.appspot.com/bug?extid=b4b0d1b35442afbf6fd2
> 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=163e740ff00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=132b758bf00000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+b4b0d1b35442afbf6fd2@syzkaller.appspotmail.com

I'm working on a fix that will remove this memory allocation entirely.

> executing program
> BUG: memory leak
> unreferenced object 0xffff888112fc9200 (size 512):
> comm "syz-executor237", pid 3648, jiffies 4294970469 (age 12.270s)
> hex dump (first 32 bytes):
> ef d3 60 85 ff ff ff ff 0c 9b d2 12 81 88 ff ff ..`.............
> 04 00 00 00 a4 01 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff814b6eb3>] kmemdup+0x23/0x50 mm/util.c:129
> [<ffffffff82219a9b>] kmemdup include/linux/fortify-string.h:456 [inline]
> [<ffffffff82219a9b>] setup_mq_sysctls+0x4b/0x1c0 ipc/mq_sysctl.c:89
> [<ffffffff822197f2>] create_ipc_ns ipc/namespace.c:63 [inline]
> [<ffffffff822197f2>] copy_ipcs+0x292/0x390 ipc/namespace.c:91
> [<ffffffff8127de7c>] create_new_namespaces+0xdc/0x4f0 kernel/nsproxy.c:90
> [<ffffffff8127e89b>] unshare_nsproxy_namespaces+0x9b/0x120 kernel/nsproxy.c:226
> [<ffffffff8123f92e>] ksys_unshare+0x2fe/0x600 kernel/fork.c:3165
> [<ffffffff8123fc42>] __do_sys_unshare kernel/fork.c:3236 [inline]
> [<ffffffff8123fc42>] __se_sys_unshare kernel/fork.c:3234 [inline]
> [<ffffffff8123fc42>] __x64_sys_unshare+0x12/0x20 kernel/fork.c:3234
> [<ffffffff845aab45>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> [<ffffffff845aab45>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> [<ffffffff8460006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
>
> BUG: memory leak
> unreferenced object 0xffff888112fd5f00 (size 256):
> comm "syz-executor237", pid 3648, jiffies 4294970469 (age 12.270s)
> hex dump (first 32 bytes):
> 00 92 fc 12 81 88 ff ff 00 00 00 00 01 00 00 00 ................
> 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff816fea1b>] kmalloc include/linux/slab.h:605 [inline]
> [<ffffffff816fea1b>] kzalloc include/linux/slab.h:733 [inline]
> [<ffffffff816fea1b>] __register_sysctl_table+0x7b/0x7f0 fs/proc/proc_sysctl.c:1344
> [<ffffffff82219b7a>] setup_mq_sysctls+0x12a/0x1c0 ipc/mq_sysctl.c:112
> [<ffffffff822197f2>] create_ipc_ns ipc/namespace.c:63 [inline]
> [<ffffffff822197f2>] copy_ipcs+0x292/0x390 ipc/namespace.c:91
> [<ffffffff8127de7c>] create_new_namespaces+0xdc/0x4f0 kernel/nsproxy.c:90
> [<ffffffff8127e89b>] unshare_nsproxy_namespaces+0x9b/0x120 kernel/nsproxy.c:226
> [<ffffffff8123f92e>] ksys_unshare+0x2fe/0x600 kernel/fork.c:3165
> [<ffffffff8123fc42>] __do_sys_unshare kernel/fork.c:3236 [inline]
> [<ffffffff8123fc42>] __se_sys_unshare kernel/fork.c:3234 [inline]
> [<ffffffff8123fc42>] __x64_sys_unshare+0x12/0x20 kernel/fork.c:3234
> [<ffffffff845aab45>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> [<ffffffff845aab45>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> [<ffffffff8460006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
>
> BUG: memory leak
> unreferenced object 0xffff888112fbba00 (size 256):
> comm "syz-executor237", pid 3648, jiffies 4294970469 (age 12.270s)
> hex dump (first 32 bytes):
> 78 ba fb 12 81 88 ff ff 00 00 00 00 01 00 00 00 x...............
> 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff816fef49>] kmalloc include/linux/slab.h:605 [inline]
> [<ffffffff816fef49>] kzalloc include/linux/slab.h:733 [inline]
> [<ffffffff816fef49>] new_dir fs/proc/proc_sysctl.c:978 [inline]
> [<ffffffff816fef49>] get_subdir fs/proc/proc_sysctl.c:1022 [inline]
> [<ffffffff816fef49>] __register_sysctl_table+0x5a9/0x7f0 fs/proc/proc_sysctl.c:1373
> [<ffffffff82219b7a>] setup_mq_sysctls+0x12a/0x1c0 ipc/mq_sysctl.c:112
> [<ffffffff822197f2>] create_ipc_ns ipc/namespace.c:63 [inline]
> [<ffffffff822197f2>] copy_ipcs+0x292/0x390 ipc/namespace.c:91
> [<ffffffff8127de7c>] create_new_namespaces+0xdc/0x4f0 kernel/nsproxy.c:90
> [<ffffffff8127e89b>] unshare_nsproxy_namespaces+0x9b/0x120 kernel/nsproxy.c:226
> [<ffffffff8123f92e>] ksys_unshare+0x2fe/0x600 kernel/fork.c:3165
> [<ffffffff8123fc42>] __do_sys_unshare kernel/fork.c:3236 [inline]
> [<ffffffff8123fc42>] __se_sys_unshare kernel/fork.c:3234 [inline]
> [<ffffffff8123fc42>] __x64_sys_unshare+0x12/0x20 kernel/fork.c:3234
> [<ffffffff845aab45>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> [<ffffffff845aab45>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> [<ffffffff8460006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
>
> BUG: memory leak
> unreferenced object 0xffff888112fbb900 (size 256):
> comm "syz-executor237", pid 3648, jiffies 4294970469 (age 12.270s)
> hex dump (first 32 bytes):
> 78 b9 fb 12 81 88 ff ff 00 00 00 00 01 00 00 00 x...............
> 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff816fef49>] kmalloc include/linux/slab.h:605 [inline]
> [<ffffffff816fef49>] kzalloc include/linux/slab.h:733 [inline]
> [<ffffffff816fef49>] new_dir fs/proc/proc_sysctl.c:978 [inline]
> [<ffffffff816fef49>] get_subdir fs/proc/proc_sysctl.c:1022 [inline]
> [<ffffffff816fef49>] __register_sysctl_table+0x5a9/0x7f0 fs/proc/proc_sysctl.c:1373
> [<ffffffff82219b7a>] setup_mq_sysctls+0x12a/0x1c0 ipc/mq_sysctl.c:112
> [<ffffffff822197f2>] create_ipc_ns ipc/namespace.c:63 [inline]
> [<ffffffff822197f2>] copy_ipcs+0x292/0x390 ipc/namespace.c:91
> [<ffffffff8127de7c>] create_new_namespaces+0xdc/0x4f0 kernel/nsproxy.c:90
> [<ffffffff8127e89b>] unshare_nsproxy_namespaces+0x9b/0x120 kernel/nsproxy.c:226
> [<ffffffff8123f92e>] ksys_unshare+0x2fe/0x600 kernel/fork.c:3165
> [<ffffffff8123fc42>] __do_sys_unshare kernel/fork.c:3236 [inline]
> [<ffffffff8123fc42>] __se_sys_unshare kernel/fork.c:3234 [inline]
> [<ffffffff8123fc42>] __x64_sys_unshare+0x12/0x20 kernel/fork.c:3234
> [<ffffffff845aab45>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> [<ffffffff845aab45>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> [<ffffffff8460006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
>
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches
>

--
Rgrds, legion