[syzbot] WARNING in smk_set_cipso (2)

[syzbot] WARNING in smk_set_cipso (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    7d900724 Merge tag 'for-5.12-rc6-tag' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1462c619d00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f91155ccddaf919c
dashboard link: https://syzkaller.appspot.com/bug?extid=77c53db50c9fff774e8e
compiler:       Debian clang version 11.0.1-2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=132c59a1d00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13acf5e9d00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+77c53db50c9fff774e8e@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 8372 at mm/page_alloc.c:4985 __alloc_pages_nodemask+0x44e/0x500 mm/page_alloc.c:5029
Modules linked in:
CPU: 1 PID: 8372 Comm: syz-executor118 Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__alloc_pages_nodemask+0x44e/0x500 mm/page_alloc.c:5029
Code: 00 48 ba 00 00 00 00 00 fc ff df e9 fb fd ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 06 fe ff ff e8 97 67 09 00 e9 fc fd ff ff <0f> 0b e9 15 fe ff ff 44 89 ed a9 00 00 08 00 75 11 81 e5 7f ff ff
RSP: 0018:ffffc90001e2fba0 EFLAGS: 00010246
RAX: ffffc90001e2fba8 RBX: ffffc90001e2fbd4 RCX: 0000000000000000
RDX: 0000000000000028 RSI: 0000000000000000 RDI: ffffc90001e2fbd0
RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffc90001e2fba8
R10: fffff520003c5f7a R11: 0000000000000000 R12: 0000000000f0ff80
R13: 0000000000040cc0 R14: 1ffff920003c5f7a R15: 000000000000000c
FS:  0000000001eb9300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020003314 CR3: 0000000012ba3000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 alloc_pages include/linux/gfp.h:561 [inline]
 kmalloc_order+0x41/0x170 mm/slab_common.c:902
 kmalloc_order_trace+0x15/0x70 mm/slab_common.c:918
 kmalloc_large include/linux/slab.h:483 [inline]
 __kmalloc_track_caller+0x26d/0x390 mm/slub.c:4554
 memdup_user_nul+0x26/0xf0 mm/util.c:260
 smk_set_cipso+0xff/0x6f0 security/smack/smackfs.c:859
 vfs_write+0x220/0xab0 fs/read_write.c:603
 ksys_write+0x11b/0x220 fs/read_write.c:658
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x43ee59
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffddac6bda8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 000000000043ee59
RDX: 0000000000f0ff7f RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000402e40 R08: 0000000000000000 R09: 0000000000400488
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402ed0
R13: 0000000000000000 R14: 00000000004ac018 R15: 0000000000400488


---
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Re: [syzbot] WARNING in smk_set_cipso (2)

[Tetsuo Handa]

Commit 7ef4c19d245f3dc2 ("smackfs: restrict bytes count in smackfs write
functions") missed that count > SMK_CIPSOMAX check applies to only
format == SMK_FIXED24_FMT case.

Reported-by: syzbot <syzbot+77c53db50c9fff774e8e@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
 security/smack/smackfs.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 22ded2c26089..1ad7d0d1ea62 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -855,6 +855,8 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
 	if (format == SMK_FIXED24_FMT &&
 	    (count < SMK_CIPSOMIN || count > SMK_CIPSOMAX))
 		return -EINVAL;
+	if (count > PAGE_SIZE)
+		return -EINVAL;
 
 	data = memdup_user_nul(buf, count);
 	if (IS_ERR(data))
-- 
2.18.4

Re: [syzbot] WARNING in smk_set_cipso (2)

[Casey Schaufler]

On 4/12/2021 6:28 AM, Tetsuo Handa wrote:
> Commit 7ef4c19d245f3dc2 ("smackfs: restrict bytes count in smackfs write
> functions") missed that count > SMK_CIPSOMAX check applies to only
> format == SMK_FIXED24_FMT case.
>
> Reported-by: syzbot <syzbot+77c53db50c9fff774e8e@syzkaller.appspotmail.com>
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

Added to smack-next. Thank you.

> ---
>  security/smack/smackfs.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
> index 22ded2c26089..1ad7d0d1ea62 100644
> --- a/security/smack/smackfs.c
> +++ b/security/smack/smackfs.c
> @@ -855,6 +855,8 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
>  	if (format == SMK_FIXED24_FMT &&
>  	    (count < SMK_CIPSOMIN || count > SMK_CIPSOMAX))
>  		return -EINVAL;
> +	if (count > PAGE_SIZE)
> +		return -EINVAL;
>  
>  	data = memdup_user_nul(buf, count);
>  	if (IS_ERR(data))