LinuxLists.cc - memory leak in cap_inode

2019-10-03 20:00:56

Subject: memory leak in cap_inode_getsecurity

Hello,

syzbot found the following crash on:

HEAD commit: 0f1a7b3f timer-of: don't use conditional expression with m..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1329640d600000
kernel config: https://syzkaller.appspot.com/x/.config?x=9d66badf12ef344c
dashboard link: https://syzkaller.appspot.com/bug?extid=942d5390db2d9624ced8
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1107b513600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email protected]

2019/10/03 14:00:37 executed programs: 36
2019/10/03 14:00:43 executed programs: 44
2019/10/03 14:00:49 executed programs: 63
BUG: memory leak
unreferenced object 0xffff8881202cb480 (size 32):
comm "syz-executor.0", pid 7246, jiffies 4294946879 (age 14.010s)
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:
[<00000000a8379648>] kmemleak_alloc_recursive
include/linux/kmemleak.h:43 [inline]
[<00000000a8379648>] slab_post_alloc_hook mm/slab.h:586 [inline]
[<00000000a8379648>] slab_alloc mm/slab.c:3319 [inline]
[<00000000a8379648>] __do_kmalloc mm/slab.c:3653 [inline]
[<00000000a8379648>] __kmalloc_track_caller+0x165/0x300 mm/slab.c:3670
[<000000008858463c>] __do_krealloc mm/slab_common.c:1638 [inline]
[<000000008858463c>] krealloc+0x7f/0xb0 mm/slab_common.c:1689
[<0000000057f9eb8e>] vfs_getxattr_alloc+0x100/0x180 fs/xattr.c:289
[<00000000c2154e30>] cap_inode_getsecurity+0x9c/0x2c0
security/commoncap.c:389
[<00000000b2664a09>] security_inode_getsecurity+0x4c/0x90
security/security.c:1314
[<00000000921624c0>] xattr_getsecurity fs/xattr.c:244 [inline]
[<00000000921624c0>] vfs_getxattr+0xf2/0x1a0 fs/xattr.c:332
[<000000001ff6977b>] getxattr+0x97/0x240 fs/xattr.c:538
[<00000000b945681f>] path_getxattr+0x6b/0xc0 fs/xattr.c:566
[<000000001a9d3fce>] __do_sys_getxattr fs/xattr.c:578 [inline]
[<000000001a9d3fce>] __se_sys_getxattr fs/xattr.c:575 [inline]
[<000000001a9d3fce>] __x64_sys_getxattr+0x28/0x30 fs/xattr.c:575
[<000000002e998337>] do_syscall_64+0x73/0x1f0
arch/x86/entry/common.c:290
[<00000000f252aa21>] 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 [email protected].

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

2022-07-31 15:26:04

by syzbot

[permalink] [raw]

Subject: Re: [syzbot] memory leak in cap_inode_getsecurity

syzbot has found a reproducer for the following issue on:

HEAD commit: 6a010258447d Merge tag 'for-linus' of git://git.armlinux.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15883fee080000
kernel config: https://syzkaller.appspot.com/x/.config?x=2a1dcc1942e30704
dashboard link: https://syzkaller.appspot.com/bug?extid=942d5390db2d9624ced8
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=1568846a080000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10f5e536080000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

executing program
BUG: memory leak
unreferenced object 0xffff88810f0ac060 (size 32):
comm "syz-executor240", pid 3622, jiffies 4294961303 (age 14.040s)
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:
[<ffffffff814c6ecd>] __do_krealloc mm/slab_common.c:1185 [inline]
[<ffffffff814c6ecd>] krealloc+0x4d/0xb0 mm/slab_common.c:1218
[<ffffffff8162625c>] vfs_getxattr_alloc+0x13c/0x1c0 fs/xattr.c:379
[<ffffffff822374b2>] cap_inode_getsecurity+0xb2/0x500 security/commoncap.c:400
[<ffffffff8223d88c>] security_inode_getsecurity+0x7c/0xb0 security/security.c:1441
[<ffffffff81625a0a>] xattr_getsecurity fs/xattr.c:327 [inline]
[<ffffffff81625a0a>] vfs_getxattr+0x22a/0x290 fs/xattr.c:423
[<ffffffff81c0ab02>] ovl_xattr_get+0x62/0xa0 fs/overlayfs/inode.c:404
[<ffffffff81624742>] __vfs_getxattr+0x72/0xa0 fs/xattr.c:401
[<ffffffff82236f52>] cap_inode_need_killpriv+0x22/0x40 security/commoncap.c:301
[<ffffffff8223d773>] security_inode_need_killpriv+0x23/0x60 security/security.c:1419
[<ffffffff8161074e>] dentry_needs_remove_privs fs/inode.c:1992 [inline]
[<ffffffff8161074e>] dentry_needs_remove_privs+0x4e/0xa0 fs/inode.c:1982
[<ffffffff815cfead>] do_truncate+0x7d/0x130 fs/open.c:57
[<ffffffff815d0169>] vfs_truncate+0x209/0x240 fs/open.c:111
[<ffffffff815d0268>] do_sys_truncate.part.0+0xc8/0xe0 fs/open.c:134
[<ffffffff815d0303>] do_sys_truncate fs/open.c:128 [inline]
[<ffffffff815d0303>] __do_sys_truncate fs/open.c:146 [inline]
[<ffffffff815d0303>] __se_sys_truncate fs/open.c:144 [inline]
[<ffffffff815d0303>] __x64_sys_truncate+0x33/0x50 fs/open.c:144
[<ffffffff845b1955>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff845b1955>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
[<ffffffff84600087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

2022-08-01 11:09:38

by Miklos Szeredi

[permalink] [raw]

Subject: Re: [syzbot] memory leak in cap_inode_getsecurity

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
master

On Sun, 31 Jul 2022 at 17:13, syzbot
<[email protected]> wrote:
>
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: 6a010258447d Merge tag 'for-linus' of git://git.armlinux.o..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=15883fee080000
> kernel config: https://syzkaller.appspot.com/x/.config?x=2a1dcc1942e30704
> dashboard link: https://syzkaller.appspot.com/bug?extid=942d5390db2d9624ced8
> 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=1568846a080000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10f5e536080000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email protected]
>
> executing program
> BUG: memory leak
> unreferenced object 0xffff88810f0ac060 (size 32):
> comm "syz-executor240", pid 3622, jiffies 4294961303 (age 14.040s)
> 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:
> [<ffffffff814c6ecd>] __do_krealloc mm/slab_common.c:1185 [inline]
> [<ffffffff814c6ecd>] krealloc+0x4d/0xb0 mm/slab_common.c:1218
> [<ffffffff8162625c>] vfs_getxattr_alloc+0x13c/0x1c0 fs/xattr.c:379
> [<ffffffff822374b2>] cap_inode_getsecurity+0xb2/0x500 security/commoncap.c:400
> [<ffffffff8223d88c>] security_inode_getsecurity+0x7c/0xb0 security/security.c:1441
> [<ffffffff81625a0a>] xattr_getsecurity fs/xattr.c:327 [inline]
> [<ffffffff81625a0a>] vfs_getxattr+0x22a/0x290 fs/xattr.c:423
> [<ffffffff81c0ab02>] ovl_xattr_get+0x62/0xa0 fs/overlayfs/inode.c:404
> [<ffffffff81624742>] __vfs_getxattr+0x72/0xa0 fs/xattr.c:401
> [<ffffffff82236f52>] cap_inode_need_killpriv+0x22/0x40 security/commoncap.c:301
> [<ffffffff8223d773>] security_inode_need_killpriv+0x23/0x60 security/security.c:1419
> [<ffffffff8161074e>] dentry_needs_remove_privs fs/inode.c:1992 [inline]
> [<ffffffff8161074e>] dentry_needs_remove_privs+0x4e/0xa0 fs/inode.c:1982
> [<ffffffff815cfead>] do_truncate+0x7d/0x130 fs/open.c:57
> [<ffffffff815d0169>] vfs_truncate+0x209/0x240 fs/open.c:111
> [<ffffffff815d0268>] do_sys_truncate.part.0+0xc8/0xe0 fs/open.c:134
> [<ffffffff815d0303>] do_sys_truncate fs/open.c:128 [inline]
> [<ffffffff815d0303>] __do_sys_truncate fs/open.c:146 [inline]
> [<ffffffff815d0303>] __se_sys_truncate fs/open.c:144 [inline]
> [<ffffffff815d0303>] __x64_sys_truncate+0x33/0x50 fs/open.c:144
> [<ffffffff845b1955>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> [<ffffffff845b1955>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> [<ffffffff84600087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
>

Attachments:

fix-leak-in-cap_inode_getsecurity.patch (1.56 kB)

2022-08-01 11:14:02

by syzbot

[permalink] [raw]

Subject: Re: [syzbot] memory leak in cap_inode_getsecurity

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: [email protected]

Tested on:

commit: 3d7cb6b0 Linux 5.19
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10aa0c2e080000
kernel config: https://syzkaller.appspot.com/x/.config?x=5466231eb53fa40e
dashboard link: https://syzkaller.appspot.com/bug?extid=942d5390db2d9624ced8
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=10e003a6080000

Note: testing is done by a robot and is best-effort only.

2022-08-01 13:16:49

by Miklos Szeredi

[permalink] [raw]

Subject: Re: [syzbot] memory leak in cap_inode_getsecurity

Attachments:

vfs_getxattr_alloc-dont-allocate-buf-on-failure.patch (384.00 B)

2022-08-03 04:52:42

by Miklos Szeredi

[permalink] [raw]

Subject: Re: memory leak in cap_inode_getsecurity

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
master

On Thu, 3 Oct 2019 at 21:59, syzbot
<[email protected]> wrote:
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: 0f1a7b3f timer-of: don't use conditional expression with m..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=1329640d600000
> kernel config: https://syzkaller.appspot.com/x/.config?x=9d66badf12ef344c
> dashboard link: https://syzkaller.appspot.com/bug?extid=942d5390db2d9624ced8
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1107b513600000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: [email protected]
>
> 2019/10/03 14:00:37 executed programs: 36
> 2019/10/03 14:00:43 executed programs: 44
> 2019/10/03 14:00:49 executed programs: 63
> BUG: memory leak
> unreferenced object 0xffff8881202cb480 (size 32):
> comm "syz-executor.0", pid 7246, jiffies 4294946879 (age 14.010s)
> 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:
> [<00000000a8379648>] kmemleak_alloc_recursive
> include/linux/kmemleak.h:43 [inline]
> [<00000000a8379648>] slab_post_alloc_hook mm/slab.h:586 [inline]
> [<00000000a8379648>] slab_alloc mm/slab.c:3319 [inline]
> [<00000000a8379648>] __do_kmalloc mm/slab.c:3653 [inline]
> [<00000000a8379648>] __kmalloc_track_caller+0x165/0x300 mm/slab.c:3670
> [<000000008858463c>] __do_krealloc mm/slab_common.c:1638 [inline]
> [<000000008858463c>] krealloc+0x7f/0xb0 mm/slab_common.c:1689
> [<0000000057f9eb8e>] vfs_getxattr_alloc+0x100/0x180 fs/xattr.c:289
> [<00000000c2154e30>] cap_inode_getsecurity+0x9c/0x2c0
> security/commoncap.c:389
> [<00000000b2664a09>] security_inode_getsecurity+0x4c/0x90
> security/security.c:1314
> [<00000000921624c0>] xattr_getsecurity fs/xattr.c:244 [inline]
> [<00000000921624c0>] vfs_getxattr+0xf2/0x1a0 fs/xattr.c:332
> [<000000001ff6977b>] getxattr+0x97/0x240 fs/xattr.c:538
> [<00000000b945681f>] path_getxattr+0x6b/0xc0 fs/xattr.c:566
> [<000000001a9d3fce>] __do_sys_getxattr fs/xattr.c:578 [inline]
> [<000000001a9d3fce>] __se_sys_getxattr fs/xattr.c:575 [inline]
> [<000000001a9d3fce>] __x64_sys_getxattr+0x28/0x30 fs/xattr.c:575
> [<000000002e998337>] do_syscall_64+0x73/0x1f0
> arch/x86/entry/common.c:290
> [<00000000f252aa21>] 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 [email protected].
>
> 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

Attachments:

vfs_getxattr_alloc-dont-allocate-buf-on-failure.patch (1.07 kB)

2022-08-03 05:17:16

by syzbot

[permalink] [raw]

Subject: Re: [syzbot] memory leak in cap_inode_getsecurity

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: [email protected]

Tested on:

commit: e2b54210 Merge tag 'flexible-array-transformations-UAP..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12c050a2080000
kernel config: https://syzkaller.appspot.com/x/.config?x=f5367bd9b8d9fa72
dashboard link: https://syzkaller.appspot.com/bug?extid=942d5390db2d9624ced8
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=17a74536080000

Note: testing is done by a robot and is best-effort only.