Re: memory leak in sctp_send_reset_streams

[Marcelo Ricardo Leitner]

On Sat, Jun 01, 2019 at 08:26:15PM +0800, Hillf Danton wrote:
> 
> Hi

Hi,

> 
> On Fri, May 31, 2019 at 02:18:06PM -0700, syzbot wrote:
> > Hello,
> > 
> > syzbot found the following crash on:
> > 
> > HEAD commit:    036e3431 Merge git://git.kernel.org/pub/scm/linux/kernel/g..
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=153cff12a00000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=8f0f63a62bb5b13c
> > dashboard link: https://syzkaller.appspot.com/bug?extid=6ad9c3bd0a218a2ab41d
> > compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12561c86a00000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15b76fd8a00000
> > 
> > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > Reported-by: syzbot+6ad9c3bd0a218a2ab41d@xxxxxxxxxxxxxxxxxxxxxxxxx
> > 
> > executing program
> > executing program
> > executing program
> > executing program
> > executing program
> > BUG: memory leak
> > unreferenced object 0xffff888123894820 (size 32):
> >    comm "syz-executor045", pid 7267, jiffies 4294943559 (age 13.660s)
> >    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:
> >      [<00000000c7e71c69>] kmemleak_alloc_recursive
> > include/linux/kmemleak.h:55 [inline]
> >      [<00000000c7e71c69>] slab_post_alloc_hook mm/slab.h:439 [inline]
> >      [<00000000c7e71c69>] slab_alloc mm/slab.c:3326 [inline]
> >      [<00000000c7e71c69>] __do_kmalloc mm/slab.c:3658 [inline]
> >      [<00000000c7e71c69>] __kmalloc+0x161/0x2c0 mm/slab.c:3669
> >      [<000000003250ed8e>] kmalloc_array include/linux/slab.h:670 [inline]
> >      [<000000003250ed8e>] kcalloc include/linux/slab.h:681 [inline]
> >      [<000000003250ed8e>] sctp_send_reset_streams+0x1ab/0x5a0 net/sctp/stream.c:302
> >      [<00000000cd899c6e>] sctp_setsockopt_reset_streams net/sctp/socket.c:4314 [inline]
> >      [<00000000cd899c6e>] sctp_setsockopt net/sctp/socket.c:4765 [inline]
> >      [<00000000cd899c6e>] sctp_setsockopt+0xc23/0x2bf0 net/sctp/socket.c:4608
> >      [<00000000ff3a21a2>] sock_common_setsockopt+0x38/0x50 net/core/sock.c:3130
> >      [<000000009eb87ae7>] __sys_setsockopt+0x98/0x120 net/socket.c:2078
> >      [<00000000e0ede6ca>] __do_sys_setsockopt net/socket.c:2089 [inline]
> >      [<00000000e0ede6ca>] __se_sys_setsockopt net/socket.c:2086 [inline]
> >      [<00000000e0ede6ca>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2086
> >      [<00000000c61155f5>] do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:301
> >      [<00000000e540958c>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> > 
> > BUG: memory leak
> > unreferenced object 0xffff888123894980 (size 32):
> >    comm "syz-executor045", pid 7268, jiffies 4294944145 (age 7.800s)
> >    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:
> >      [<00000000c7e71c69>] kmemleak_alloc_recursive
> > include/linux/kmemleak.h:55 [inline]
> >      [<00000000c7e71c69>] slab_post_alloc_hook mm/slab.h:439 [inline]
> >      [<00000000c7e71c69>] slab_alloc mm/slab.c:3326 [inline]
> >      [<00000000c7e71c69>] __do_kmalloc mm/slab.c:3658 [inline]
> >      [<00000000c7e71c69>] __kmalloc+0x161/0x2c0 mm/slab.c:3669
> >      [<000000003250ed8e>] kmalloc_array include/linux/slab.h:670 [inline]
> >      [<000000003250ed8e>] kcalloc include/linux/slab.h:681 [inline]
> >      [<000000003250ed8e>] sctp_send_reset_streams+0x1ab/0x5a0 net/sctp/stream.c:302
> >      [<00000000cd899c6e>] sctp_setsockopt_reset_streams net/sctp/socket.c:4314 [inline]
> >      [<00000000cd899c6e>] sctp_setsockopt net/sctp/socket.c:4765 [inline]
> >      [<00000000cd899c6e>] sctp_setsockopt+0xc23/0x2bf0 net/sctp/socket.c:4608
> >      [<00000000ff3a21a2>] sock_common_setsockopt+0x38/0x50 net/core/sock.c:3130
> >      [<000000009eb87ae7>] __sys_setsockopt+0x98/0x120 net/socket.c:2078
> >      [<00000000e0ede6ca>] __do_sys_setsockopt net/socket.c:2089 [inline]
> >      [<00000000e0ede6ca>] __se_sys_setsockopt net/socket.c:2086 [inline]
> >      [<00000000e0ede6ca>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2086
> >      [<00000000c61155f5>] do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:301
> >      [<00000000e540958c>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> > 
> > 
> > 
> > ---
> > This bug 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@xxxxxxxxxxxxxxxxx
> > 
> > syzbot will keep track of this bug report. See:
> > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> > syzbot can test patches for this bug, for details see:
> > https://goo.gl/tpsmEJ#testing-patches
> > 
> The following tiny change is prepared based on the info listed above and I want
> to know if it works for you.
> 
> thanks
> Hillf
> ------->8---
> diff --git a/net/sctp/stream.c b/net/sctp/stream.c
> index 93ed078..d3e2f03 100644
> --- a/net/sctp/stream.c
> +++ b/net/sctp/stream.c
> @@ -310,6 +310,7 @@ int sctp_send_reset_streams(struct sctp_association *asoc,
> 
> 	if (out && !sctp_stream_outq_is_empty(stream, str_nums, nstr_list)) {
> 		retval = -EAGAIN;
> +		kfree(nstr_list);

Yes it does. Thanks Hillf.

> 		goto out;
> 	}
> 
> --
>