[syzbot] [crypto?] KMSAN: uninit-value in af_alg_free_resources

[syzbot] [crypto?] KMSAN: uninit-value in af_alg_free_resources

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    3f01e9fed845 Merge tag 'linux-watchdog-6.5-rc2' of git://w..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=14bac16aa80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1542573e31cfbec5
dashboard link: https://syzkaller.appspot.com/bug?extid=cba21d50095623218389
compiler:       Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15dd215aa80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14530318a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4f212a7e36fe/disk-3f01e9fe.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/de6b12daf908/vmlinux-3f01e9fe.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2c1992ff2aaa/bzImage-3f01e9fe.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cba21d50095623218389@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in af_alg_free_sg crypto/af_alg.c:545 [inline]
BUG: KMSAN: uninit-value in af_alg_free_areq_sgls crypto/af_alg.c:778 [inline]
BUG: KMSAN: uninit-value in af_alg_free_resources+0x3d1/0xf60 crypto/af_alg.c:1117
 af_alg_free_sg crypto/af_alg.c:545 [inline]
 af_alg_free_areq_sgls crypto/af_alg.c:778 [inline]
 af_alg_free_resources+0x3d1/0xf60 crypto/af_alg.c:1117
 _skcipher_recvmsg crypto/algif_skcipher.c:144 [inline]
 skcipher_recvmsg+0x6a0/0x1a20 crypto/algif_skcipher.c:157
 sock_recvmsg_nosec net/socket.c:1020 [inline]
 sock_recvmsg net/socket.c:1041 [inline]
 __sys_recvfrom+0x505/0x810 net/socket.c:2186
 __do_sys_recvfrom net/socket.c:2204 [inline]
 __se_sys_recvfrom net/socket.c:2200 [inline]
 __x64_sys_recvfrom+0x126/0x1d0 net/socket.c:2200
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Uninit was created at:
 slab_post_alloc_hook+0x12f/0xb70 mm/slab.h:767
 slab_alloc_node mm/slub.c:3470 [inline]
 __kmem_cache_alloc_node+0x536/0x8d0 mm/slub.c:3509
 __do_kmalloc_node mm/slab_common.c:984 [inline]
 __kmalloc+0x121/0x3c0 mm/slab_common.c:998
 kmalloc include/linux/slab.h:586 [inline]
 sock_kmalloc+0x128/0x1c0 net/core/sock.c:2683
 af_alg_alloc_areq+0x41/0x2a0 crypto/af_alg.c:1188
 _skcipher_recvmsg crypto/algif_skcipher.c:71 [inline]
 skcipher_recvmsg+0x514/0x1a20 crypto/algif_skcipher.c:157
 sock_recvmsg_nosec net/socket.c:1020 [inline]
 sock_recvmsg net/socket.c:1041 [inline]
 __sys_recvfrom+0x505/0x810 net/socket.c:2186
 __do_sys_recvfrom net/socket.c:2204 [inline]
 __se_sys_recvfrom net/socket.c:2200 [inline]
 __x64_sys_recvfrom+0x126/0x1d0 net/socket.c:2200
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

CPU: 0 PID: 5031 Comm: syz-executor370 Not tainted 6.5.0-rc1-syzkaller-00006-g3f01e9fed845 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023
=====================================================


---
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If the bug is already fixed, let syzbot know by replying with:
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#syz undup

Re: [syzbot] [crypto?] KMSAN: uninit-value in af_alg_free_resources

[Pavel Skripkin]

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Hi Syzbot,

Syzbot <syzbot+cba21d50095623218389@syzkaller.appspotmail.com> says:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    3f01e9fed845 Merge tag 'linux-watchdog-6.5-rc2' of git://w..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=14bac16aa80000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=1542573e31cfbec5
> dashboard link: https://syzkaller.appspot.com/bug?extid=cba21d50095623218389
> compiler:       Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15dd215aa80000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14530318a80000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/4f212a7e36fe/disk-3f01e9fe.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/de6b12daf908/vmlinux-3f01e9fe.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/2c1992ff2aaa/bzImage-3f01e9fe.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+cba21d50095623218389@syzkaller.appspotmail.com

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





With regards,
Pavel Skripkin

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[-- Type: text/plain, Size: 379 bytes --]

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 06b15b9f661c..4e4f2d837481 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -1241,6 +1241,8 @@ int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
 				return -ENOMEM;
 		}
 
+		rsgl->sgl.need_unpin = 0;
+
 		rsgl->sgl.sgt.sgl = rsgl->sgl.sgl;
 		rsgl->sgl.sgt.nents = 0;
 		rsgl->sgl.sgt.orig_nents = 0;

Re: [syzbot] [crypto?] KMSAN: uninit-value in af_alg_free_resources

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+cba21d50095623218389@syzkaller.appspotmail.com

Tested on:

commit:         4b810bf0 Merge tag 'erofs-for-6.5-rc2-fixes' of git://..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1584e7d4a80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=81133937a108454e
dashboard link: https://syzkaller.appspot.com/bug?extid=cba21d50095623218389
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1305e904a80000

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

Re: [syzbot] [crypto?] KMSAN: uninit-value in af_alg_free_resources

[Herbert Xu]

On Fri, Jul 14, 2023 at 05:56:54PM +0300, Pavel Skripkin wrote:
>
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+cba21d50095623218389@syzkaller.appspotmail.com
> 
> #syz test
> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

Will you be submitting this patch?

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [syzbot] [crypto?] KMSAN: uninit-value in af_alg_free_resources

[Pavel Skripkin]

Hi Herbert,

Herbert Xu <herbert@gondor.apana.org.au> says:
> On Fri, Jul 14, 2023 at 05:56:54PM +0300, Pavel Skripkin wrote:
>>
>> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> > Reported-by: syzbot+cba21d50095623218389@syzkaller.appspotmail.com
>> 
>> #syz test
>> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> 
> Will you be submitting this patch?
> 

Yeah, will do it shortly. This bug got lost in my todo list...



With regards,
Pavel Skripkin