Re: WARNING in apparmor_cred_free
On Fri, 11 Jan 2019, Casey Schaufler wrote: > >From 47134986133c822e1d88860fa2b108f92c97a7ff Mon Sep 17 00:00:00 2001 > From: Casey Schaufler > Date: Fri, 11 Jan 2019 17:31:50 -0800 > Subject: [PATCH 1/2] LSM: Check for NULL cred-security on free > > Check that the cred security blob has been set before trying > to clean it up. There is a case during credential initialization > that could result in this. > > Signed-off-by: Casey Schaufler Applied to git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git fixes-v5.0-rc2 NOTE: For patches which you are submitting for inclusion, start a new thread and include [PATCH] in the subject line. -- James Morris
Re: WARNING in apparmor_cred_free
On 1/16/19 1:14 PM, James Morris wrote:
> On Fri, 11 Jan 2019, Casey Schaufler wrote:
>
>> >From 47134986133c822e1d88860fa2b108f92c97a7ff Mon Sep 17 00:00:00 2001
>> From: Casey Schaufler
>> Date: Fri, 11 Jan 2019 17:31:50 -0800
>> Subject: [PATCH 1/2] LSM: Check for NULL cred-security on free
>>
>> Check that the cred security blob has been set before trying
>> to clean it up. There is a case during credential initialization
>> that could result in this.
>>
>> Signed-off-by: Casey Schaufler
>
> JJ: does this fix the problem?
>
sorry for not responding earlier, yes it does.
Acked-by: John Johansen
>> ---
>> security/security.c | 7 +++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/security/security.c b/security/security.c
>> index a618e22df5c6..7bffc86d4e87 100644
>> --- a/security/security.c
>> +++ b/security/security.c
>> @@ -1477,6 +1477,13 @@ int security_cred_alloc_blank(struct cred *cred,
>> gfp_t gfp)
>>
>> void security_cred_free(struct cred *cred)
>> {
>> +/*
>> + * There is a failure case in prepare_creds() that
>> + * may result in a call here with ->security being NULL.
>> + */
>> +if (unlikely(cred->security == NULL))
>> +return;
>> +
>> call_void_hook(cred_free, cred);
>>
>> kfree(cred->security);
>>
>
Re: WARNING in apparmor_cred_free
On Fri, 11 Jan 2019, Casey Schaufler wrote:
> >From 47134986133c822e1d88860fa2b108f92c97a7ff Mon Sep 17 00:00:00 2001
> From: Casey Schaufler
> Date: Fri, 11 Jan 2019 17:31:50 -0800
> Subject: [PATCH 1/2] LSM: Check for NULL cred-security on free
>
> Check that the cred security blob has been set before trying
> to clean it up. There is a case during credential initialization
> that could result in this.
>
> Signed-off-by: Casey Schaufler
JJ: does this fix the problem?
> ---
> security/security.c | 7 +++
> 1 file changed, 7 insertions(+)
>
> diff --git a/security/security.c b/security/security.c
> index a618e22df5c6..7bffc86d4e87 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1477,6 +1477,13 @@ int security_cred_alloc_blank(struct cred *cred, gfp_t
> gfp)
>
> void security_cred_free(struct cred *cred)
> {
> + /*
> + * There is a failure case in prepare_creds() that
> + * may result in a call here with ->security being NULL.
> + */
> + if (unlikely(cred->security == NULL))
> + return;
> +
> call_void_hook(cred_free, cred);
>
> kfree(cred->security);
>
--
James Morris
Re: WARNING in apparmor_cred_free
On Sat, Jan 12, 2019 at 2:47 AM Casey Schaufler wrote: > > On 1/11/2019 3:20 PM, Casey Schaufler wrote: > > On 1/11/2019 2:43 PM, Casey Schaufler wrote: > >> On 1/11/2019 2:30 PM, John Johansen wrote: > >>> On 1/11/19 2:11 PM, Casey Schaufler wrote: > On 1/11/2019 1:43 AM, syzbot wrote: > > Hello, > > > > syzbot found the following crash on: > > > > HEAD commit:b808822a75a3 Add linux-next specific files for 20190111 > > git tree: linux-next > > console output: https://syzkaller.appspot.com/x/log.txt?x=179c22f740 > > kernel config: > > https://syzkaller.appspot.com/x/.config?x=c052ead0aed5001b > > dashboard link: > > https://syzkaller.appspot.com/bug?extid=69ca07954461f189e808 > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > syz repro: > > https://syzkaller.appspot.com/x/repro.syz?x=162d947f40 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=139f6c3740 > > > > IMPORTANT: if you fix the bug, please add the following tag to the > > commit: > > Reported-by: syzbot+69ca07954461f189e...@syzkaller.appspotmail.com /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ Please include the tag for tracking purposes. > > [ cut here ] > > AppArmor WARN cred_label: ((!blob)): > > WARNING: CPU: 0 PID: 0 at security/apparmor/include/cred.h:30 > > cred_label security/apparmor/include/cred.h:30 [inline] > > WARNING: CPU: 0 PID: 0 at security/apparmor/include/cred.h:30 > > apparmor_cred_free+0x12f/0x1a0 security/apparmor/lsm.c:62 > > Kernel panic - not syncing: panic_on_warn set ... > > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.0.0-rc1-next-20190111 #10 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > Google 01/01/2011 > > Call Trace: > > > > __dump_stack lib/dump_stack.c:77 [inline] > > dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 > > panic+0x2cb/0x65c kernel/panic.c:214 > > __warn.cold+0x20/0x48 kernel/panic.c:571 > > report_bug+0x263/0x2b0 lib/bug.c:186 > > fixup_bug arch/x86/kernel/traps.c:178 [inline] > > fixup_bug arch/x86/kernel/traps.c:173 [inline] > > do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 > > do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290 > > invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 > > RIP: 0010:cred_label security/apparmor/include/cred.h:30 [inline] > > RIP: 0010:apparmor_cred_free+0x12f/0x1a0 security/apparmor/lsm.c:62 > > Code: 7c 88 48 c7 c7 00 d0 7c 88 e8 fd 70 f2 fd 0f 0b eb a9 e8 54 3f 29 > > fe 48 c7 c6 c0 df 7c 88 48 c7 c7 00 d0 7c 88 e8 e1 70 f2 fd <0f> 0b 48 > > b8 00 00 00 00 00 fc ff df 80 38 00 75 4a 4c 8b 2c 25 00 > > RSP: 0018:8880ae6079f8 EFLAGS: 00010286 > > RAX: RBX: RCX: > > RDX: 0100 RSI: 81687fa6 RDI: 0006 > > RBP: 8880ae607a18 R08: 8987dec0 R09: > > R10: R11: R12: 8880a86b3100 > > R13: 8880a86b3100 R14: 8880a86b3188 R15: dc00 > > security_cred_free+0x4b/0xf0 security/security.c:1490 > The obvious thing to do is put a check in security_cred_free > for a NULL cred->security, in which case the LSM hooks > wouldn't get called. > >>> Right, but the question is should we? To my thinking we shouldn't > >>> ever have a cred without cred->security, unless the cred was > >>> allocated but a later step in its construction, say allocating > >>> ->security failed. > >> If allocating ->security fails in security_cred_alloc_blank() > >> or security_prepare_creds() you don't have to do anything but > >> fail because the LSM hooks are not called before the allocation. > >> > >>> In which case I'd rather see the cred directly freed and not > >>> call into security_cred_free() as I like being able to detect > >>> corrupt creds. > >> I think we need to look for some bit of code that's setting > >> cred->security to NULL inappropriately. > > If security_cred_alloc_blank() fails for lack of memory > > in cred_alloc_blank() abort_creds() will be called. This > > in turn calls put_cred() and put_cred_rcu(), which will > > call security_cred_free() with ->security set to NULL. > > > > put_cred_rcu() is the only caller of security_cred_free(). > > The ->security == NULL check can be in either put_cred_rcu() > > or in security_cred_free(). I suggest the latter as the > > cleanest option. > > From 47134986133c822e1d88860fa2b108f92c97a7ff Mon Sep 17 00:00:00 2001 > From: Casey Schaufler > Date: Fri, 11 Jan 2019 17:31:50 -0800 > Subject: [PATCH 1/2] LSM: Check for NULL cred-security on free > > Check that the cred security blob has been set before trying > to clean it up. There is a case during credential initialization > that could result in this. > > Signed-off-by: Ca
Re: WARNING in apparmor_cred_free
On 1/11/2019 3:20 PM, Casey Schaufler wrote: > On 1/11/2019 2:43 PM, Casey Schaufler wrote: >> On 1/11/2019 2:30 PM, John Johansen wrote: >>> On 1/11/19 2:11 PM, Casey Schaufler wrote: On 1/11/2019 1:43 AM, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: b808822a75a3 Add linux-next specific files for 20190111 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=179c22f740 > kernel config: https://syzkaller.appspot.com/x/.config?x=c052ead0aed5001b > dashboard link: > https://syzkaller.appspot.com/bug?extid=69ca07954461f189e808 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=162d947f40 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=139f6c3740 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+69ca07954461f189e...@syzkaller.appspotmail.com > > [ cut here ] > AppArmor WARN cred_label: ((!blob)): > WARNING: CPU: 0 PID: 0 at security/apparmor/include/cred.h:30 cred_label > security/apparmor/include/cred.h:30 [inline] > WARNING: CPU: 0 PID: 0 at security/apparmor/include/cred.h:30 > apparmor_cred_free+0x12f/0x1a0 security/apparmor/lsm.c:62 > Kernel panic - not syncing: panic_on_warn set ... > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.0.0-rc1-next-20190111 #10 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 > panic+0x2cb/0x65c kernel/panic.c:214 > __warn.cold+0x20/0x48 kernel/panic.c:571 > report_bug+0x263/0x2b0 lib/bug.c:186 > fixup_bug arch/x86/kernel/traps.c:178 [inline] > fixup_bug arch/x86/kernel/traps.c:173 [inline] > do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 > do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290 > invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 > RIP: 0010:cred_label security/apparmor/include/cred.h:30 [inline] > RIP: 0010:apparmor_cred_free+0x12f/0x1a0 security/apparmor/lsm.c:62 > Code: 7c 88 48 c7 c7 00 d0 7c 88 e8 fd 70 f2 fd 0f 0b eb a9 e8 54 3f 29 > fe 48 c7 c6 c0 df 7c 88 48 c7 c7 00 d0 7c 88 e8 e1 70 f2 fd <0f> 0b 48 b8 > 00 00 00 00 00 fc ff df 80 38 00 75 4a 4c 8b 2c 25 00 > RSP: 0018:8880ae6079f8 EFLAGS: 00010286 > RAX: RBX: RCX: > RDX: 0100 RSI: 81687fa6 RDI: 0006 > RBP: 8880ae607a18 R08: 8987dec0 R09: > R10: R11: R12: 8880a86b3100 > R13: 8880a86b3100 R14: 8880a86b3188 R15: dc00 > security_cred_free+0x4b/0xf0 security/security.c:1490 The obvious thing to do is put a check in security_cred_free for a NULL cred->security, in which case the LSM hooks wouldn't get called. >>> Right, but the question is should we? To my thinking we shouldn't >>> ever have a cred without cred->security, unless the cred was >>> allocated but a later step in its construction, say allocating >>> ->security failed. >> If allocating ->security fails in security_cred_alloc_blank() >> or security_prepare_creds() you don't have to do anything but >> fail because the LSM hooks are not called before the allocation. >> >>> In which case I'd rather see the cred directly freed and not >>> call into security_cred_free() as I like being able to detect >>> corrupt creds. >> I think we need to look for some bit of code that's setting >> cred->security to NULL inappropriately. > If security_cred_alloc_blank() fails for lack of memory > in cred_alloc_blank() abort_creds() will be called. This > in turn calls put_cred() and put_cred_rcu(), which will > call security_cred_free() with ->security set to NULL. > > put_cred_rcu() is the only caller of security_cred_free(). > The ->security == NULL check can be in either put_cred_rcu() > or in security_cred_free(). I suggest the latter as the > cleanest option. >From 47134986133c822e1d88860fa2b108f92c97a7ff Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Fri, 11 Jan 2019 17:31:50 -0800 Subject: [PATCH 1/2] LSM: Check for NULL cred-security on free Check that the cred security blob has been set before trying to clean it up. There is a case during credential initialization that could result in this. Signed-off-by: Casey Schaufler --- security/security.c | 7 +++ 1 file changed, 7 insertions(+) diff --git a/security/security.c b/security/security.c index a618e22df5c6..7bffc86d4e87 100644 --- a/security/security.c +++ b/security/security.c @@ -1477,6 +1477,13 @@ int security_cred_alloc_blank(struct cred *cred, gfp_t gfp) void security_cred_free(stru
Re: WARNING in apparmor_cred_free
On 1/11/2019 2:43 PM, Casey Schaufler wrote: > On 1/11/2019 2:30 PM, John Johansen wrote: >> On 1/11/19 2:11 PM, Casey Schaufler wrote: >>> On 1/11/2019 1:43 AM, syzbot wrote: Hello, syzbot found the following crash on: HEAD commit: b808822a75a3 Add linux-next specific files for 20190111 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=179c22f740 kernel config: https://syzkaller.appspot.com/x/.config?x=c052ead0aed5001b dashboard link: https://syzkaller.appspot.com/bug?extid=69ca07954461f189e808 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=162d947f40 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=139f6c3740 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+69ca07954461f189e...@syzkaller.appspotmail.com [ cut here ] AppArmor WARN cred_label: ((!blob)): WARNING: CPU: 0 PID: 0 at security/apparmor/include/cred.h:30 cred_label security/apparmor/include/cred.h:30 [inline] WARNING: CPU: 0 PID: 0 at security/apparmor/include/cred.h:30 apparmor_cred_free+0x12f/0x1a0 security/apparmor/lsm.c:62 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.0.0-rc1-next-20190111 #10 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 panic+0x2cb/0x65c kernel/panic.c:214 __warn.cold+0x20/0x48 kernel/panic.c:571 report_bug+0x263/0x2b0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] fixup_bug arch/x86/kernel/traps.c:173 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 RIP: 0010:cred_label security/apparmor/include/cred.h:30 [inline] RIP: 0010:apparmor_cred_free+0x12f/0x1a0 security/apparmor/lsm.c:62 Code: 7c 88 48 c7 c7 00 d0 7c 88 e8 fd 70 f2 fd 0f 0b eb a9 e8 54 3f 29 fe 48 c7 c6 c0 df 7c 88 48 c7 c7 00 d0 7c 88 e8 e1 70 f2 fd <0f> 0b 48 b8 00 00 00 00 00 fc ff df 80 38 00 75 4a 4c 8b 2c 25 00 RSP: 0018:8880ae6079f8 EFLAGS: 00010286 RAX: RBX: RCX: RDX: 0100 RSI: 81687fa6 RDI: 0006 RBP: 8880ae607a18 R08: 8987dec0 R09: R10: R11: R12: 8880a86b3100 R13: 8880a86b3100 R14: 8880a86b3188 R15: dc00 security_cred_free+0x4b/0xf0 security/security.c:1490 >>> The obvious thing to do is put a check in security_cred_free >>> for a NULL cred->security, in which case the LSM hooks >>> wouldn't get called. >> Right, but the question is should we? To my thinking we shouldn't >> ever have a cred without cred->security, unless the cred was >> allocated but a later step in its construction, say allocating >> ->security failed. > If allocating ->security fails in security_cred_alloc_blank() > or security_prepare_creds() you don't have to do anything but > fail because the LSM hooks are not called before the allocation. > >> In which case I'd rather see the cred directly freed and not >> call into security_cred_free() as I like being able to detect >> corrupt creds. > I think we need to look for some bit of code that's setting > cred->security to NULL inappropriately. If security_cred_alloc_blank() fails for lack of memory in cred_alloc_blank() abort_creds() will be called. This in turn calls put_cred() and put_cred_rcu(), which will call security_cred_free() with ->security set to NULL. put_cred_rcu() is the only caller of security_cred_free(). The ->security == NULL check can be in either put_cred_rcu() or in security_cred_free(). I suggest the latter as the cleanest option.
Re: WARNING in apparmor_cred_free
On 1/11/2019 2:30 PM, John Johansen wrote: > On 1/11/19 2:11 PM, Casey Schaufler wrote: >> On 1/11/2019 1:43 AM, syzbot wrote: >>> Hello, >>> >>> syzbot found the following crash on: >>> >>> HEAD commit: b808822a75a3 Add linux-next specific files for 20190111 >>> git tree: linux-next >>> console output: https://syzkaller.appspot.com/x/log.txt?x=179c22f740 >>> kernel config: https://syzkaller.appspot.com/x/.config?x=c052ead0aed5001b >>> dashboard link: https://syzkaller.appspot.com/bug?extid=69ca07954461f189e808 >>> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=162d947f40 >>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=139f6c3740 >>> >>> IMPORTANT: if you fix the bug, please add the following tag to the commit: >>> Reported-by: syzbot+69ca07954461f189e...@syzkaller.appspotmail.com >>> >>> [ cut here ] >>> AppArmor WARN cred_label: ((!blob)): >>> WARNING: CPU: 0 PID: 0 at security/apparmor/include/cred.h:30 cred_label >>> security/apparmor/include/cred.h:30 [inline] >>> WARNING: CPU: 0 PID: 0 at security/apparmor/include/cred.h:30 >>> apparmor_cred_free+0x12f/0x1a0 security/apparmor/lsm.c:62 >>> Kernel panic - not syncing: panic_on_warn set ... >>> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.0.0-rc1-next-20190111 #10 >>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >>> Google 01/01/2011 >>> Call Trace: >>> >>> __dump_stack lib/dump_stack.c:77 [inline] >>> dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 >>> panic+0x2cb/0x65c kernel/panic.c:214 >>> __warn.cold+0x20/0x48 kernel/panic.c:571 >>> report_bug+0x263/0x2b0 lib/bug.c:186 >>> fixup_bug arch/x86/kernel/traps.c:178 [inline] >>> fixup_bug arch/x86/kernel/traps.c:173 [inline] >>> do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 >>> do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290 >>> invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 >>> RIP: 0010:cred_label security/apparmor/include/cred.h:30 [inline] >>> RIP: 0010:apparmor_cred_free+0x12f/0x1a0 security/apparmor/lsm.c:62 >>> Code: 7c 88 48 c7 c7 00 d0 7c 88 e8 fd 70 f2 fd 0f 0b eb a9 e8 54 3f 29 fe >>> 48 c7 c6 c0 df 7c 88 48 c7 c7 00 d0 7c 88 e8 e1 70 f2 fd <0f> 0b 48 b8 00 >>> 00 00 00 00 fc ff df 80 38 00 75 4a 4c 8b 2c 25 00 >>> RSP: 0018:8880ae6079f8 EFLAGS: 00010286 >>> RAX: RBX: RCX: >>> RDX: 0100 RSI: 81687fa6 RDI: 0006 >>> RBP: 8880ae607a18 R08: 8987dec0 R09: >>> R10: R11: R12: 8880a86b3100 >>> R13: 8880a86b3100 R14: 8880a86b3188 R15: dc00 >>> security_cred_free+0x4b/0xf0 security/security.c:1490 >> The obvious thing to do is put a check in security_cred_free >> for a NULL cred->security, in which case the LSM hooks >> wouldn't get called. > Right, but the question is should we? To my thinking we shouldn't > ever have a cred without cred->security, unless the cred was > allocated but a later step in its construction, say allocating > ->security failed. If allocating ->security fails in security_cred_alloc_blank() or security_prepare_creds() you don't have to do anything but fail because the LSM hooks are not called before the allocation. > In which case I'd rather see the cred directly freed and not > call into security_cred_free() as I like being able to detect > corrupt creds. I think we need to look for some bit of code that's setting cred->security to NULL inappropriately. > We certainly can still do the check for security on only live creds > but I would like to understand this particular failure better first > >> It's not clear to me how we got a cred >> that doesn't have an allocated security blob. > I have been trying to figure that one out as well. > > >>> put_cred_rcu+0x21f/0x6e0 kernel/cred.c:118 >>> __rcu_reclaim kernel/rcu/rcu.h:240 [inline] >>> rcu_do_batch kernel/rcu/tree.c:2486 [inline] >>> invoke_rcu_callbacks kernel/rcu/tree.c:2799 [inline] >>> rcu_core+0xc4a/0x1680 kernel/rcu/tree.c:2780 >>> __do_softirq+0x30b/0xb11 kernel/softirq.c:292 >>> invoke_softirq kernel/softirq.c:373 [inline] >>> irq_exit+0x180/0x1d0 kernel/softirq.c:413 >>> exiting_irq arch/x86/include/asm/apic.h:536 [inline] >>> smp_apic_timer_interrupt+0x1b7/0x760 arch/x86/kernel/apic/apic.c:1062 >>> apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 >>> >>> RIP: 0010:native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:58 >>> Code: ff ff ff 48 89 c7 48 89 45 d8 e8 79 6f d0 f9 48 8b 45 d8 e9 ce fe ff >>> ff 48 89 df e8 68 6f d0 f9 eb 82 90 90 90 90 90 90 fb f4 0f 1f 00 66 >>> 2e 0f 1f 84 00 00 00 00 00 f4 c3 90 90 90 90 90 90 >>> RSP: 0018:89807c60 EFLAGS: 0282 ORIG_RAX: ff13 >>> RAX: 11325061 RBX: 11300f8f RCX: >>> RDX: dc00 RSI: 0001 RDI: 8987
Re: WARNING in apparmor_cred_free
On 1/11/19 2:11 PM, Casey Schaufler wrote: > On 1/11/2019 1:43 AM, syzbot wrote: >> Hello, >> >> syzbot found the following crash on: >> >> HEAD commit: b808822a75a3 Add linux-next specific files for 20190111 >> git tree: linux-next >> console output: https://syzkaller.appspot.com/x/log.txt?x=179c22f740 >> kernel config: https://syzkaller.appspot.com/x/.config?x=c052ead0aed5001b >> dashboard link: https://syzkaller.appspot.com/bug?extid=69ca07954461f189e808 >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=162d947f40 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=139f6c3740 >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+69ca07954461f189e...@syzkaller.appspotmail.com >> >> [ cut here ] >> AppArmor WARN cred_label: ((!blob)): >> WARNING: CPU: 0 PID: 0 at security/apparmor/include/cred.h:30 cred_label >> security/apparmor/include/cred.h:30 [inline] >> WARNING: CPU: 0 PID: 0 at security/apparmor/include/cred.h:30 >> apparmor_cred_free+0x12f/0x1a0 security/apparmor/lsm.c:62 >> Kernel panic - not syncing: panic_on_warn set ... >> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.0.0-rc1-next-20190111 #10 >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >> Google 01/01/2011 >> Call Trace: >> >> __dump_stack lib/dump_stack.c:77 [inline] >> dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 >> panic+0x2cb/0x65c kernel/panic.c:214 >> __warn.cold+0x20/0x48 kernel/panic.c:571 >> report_bug+0x263/0x2b0 lib/bug.c:186 >> fixup_bug arch/x86/kernel/traps.c:178 [inline] >> fixup_bug arch/x86/kernel/traps.c:173 [inline] >> do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 >> do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290 >> invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 >> RIP: 0010:cred_label security/apparmor/include/cred.h:30 [inline] >> RIP: 0010:apparmor_cred_free+0x12f/0x1a0 security/apparmor/lsm.c:62 >> Code: 7c 88 48 c7 c7 00 d0 7c 88 e8 fd 70 f2 fd 0f 0b eb a9 e8 54 3f 29 fe >> 48 c7 c6 c0 df 7c 88 48 c7 c7 00 d0 7c 88 e8 e1 70 f2 fd <0f> 0b 48 b8 00 00 >> 00 00 00 fc ff df 80 38 00 75 4a 4c 8b 2c 25 00 >> RSP: 0018:8880ae6079f8 EFLAGS: 00010286 >> RAX: RBX: RCX: >> RDX: 0100 RSI: 81687fa6 RDI: 0006 >> RBP: 8880ae607a18 R08: 8987dec0 R09: >> R10: R11: R12: 8880a86b3100 >> R13: 8880a86b3100 R14: 8880a86b3188 R15: dc00 >> security_cred_free+0x4b/0xf0 security/security.c:1490 > > The obvious thing to do is put a check in security_cred_free > for a NULL cred->security, in which case the LSM hooks > wouldn't get called. Right, but the question is should we? To my thinking we shouldn't ever have a cred without cred->security, unless the cred was allocated but a later step in its construction, say allocating ->security failed. In which case I'd rather see the cred directly freed and not call into security_cred_free() as I like being able to detect corrupt creds. We certainly can still do the check for security on only live creds but I would like to understand this particular failure better first > It's not clear to me how we got a cred > that doesn't have an allocated security blob. I have been trying to figure that one out as well. > >> put_cred_rcu+0x21f/0x6e0 kernel/cred.c:118 >> __rcu_reclaim kernel/rcu/rcu.h:240 [inline] >> rcu_do_batch kernel/rcu/tree.c:2486 [inline] >> invoke_rcu_callbacks kernel/rcu/tree.c:2799 [inline] >> rcu_core+0xc4a/0x1680 kernel/rcu/tree.c:2780 >> __do_softirq+0x30b/0xb11 kernel/softirq.c:292 >> invoke_softirq kernel/softirq.c:373 [inline] >> irq_exit+0x180/0x1d0 kernel/softirq.c:413 >> exiting_irq arch/x86/include/asm/apic.h:536 [inline] >> smp_apic_timer_interrupt+0x1b7/0x760 arch/x86/kernel/apic/apic.c:1062 >> apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 >> >> RIP: 0010:native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:58 >> Code: ff ff ff 48 89 c7 48 89 45 d8 e8 79 6f d0 f9 48 8b 45 d8 e9 ce fe ff >> ff 48 89 df e8 68 6f d0 f9 eb 82 90 90 90 90 90 90 fb f4 0f 1f 00 66 2e >> 0f 1f 84 00 00 00 00 00 f4 c3 90 90 90 90 90 90 >> RSP: 0018:89807c60 EFLAGS: 0282 ORIG_RAX: ff13 >> RAX: 11325061 RBX: 11300f8f RCX: >> RDX: dc00 RSI: 0001 RDI: 8987e73c >> RBP: 89807d20 R08: 8987dec0 R09: >> R10: R11: R12: >> R13: 89807cf8 R14: R15: 899282f8 >> arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:555 >> default_idle_call+0x36/0x90 kernel/sched/idle.c:93 >> cpuidle_idle_call kernel/sched/idle.c:153 [inline] >> do_idle+0x386/0x5d0 kernel/sched/idle.c:26
Re: WARNING in apparmor_cred_free
On 1/11/2019 1:43 AM, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: b808822a75a3 Add linux-next specific files for 20190111 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=179c22f740 > kernel config: https://syzkaller.appspot.com/x/.config?x=c052ead0aed5001b > dashboard link: https://syzkaller.appspot.com/bug?extid=69ca07954461f189e808 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=162d947f40 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=139f6c3740 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+69ca07954461f189e...@syzkaller.appspotmail.com > > [ cut here ] > AppArmor WARN cred_label: ((!blob)): > WARNING: CPU: 0 PID: 0 at security/apparmor/include/cred.h:30 cred_label > security/apparmor/include/cred.h:30 [inline] > WARNING: CPU: 0 PID: 0 at security/apparmor/include/cred.h:30 > apparmor_cred_free+0x12f/0x1a0 security/apparmor/lsm.c:62 > Kernel panic - not syncing: panic_on_warn set ... > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.0.0-rc1-next-20190111 #10 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 > panic+0x2cb/0x65c kernel/panic.c:214 > __warn.cold+0x20/0x48 kernel/panic.c:571 > report_bug+0x263/0x2b0 lib/bug.c:186 > fixup_bug arch/x86/kernel/traps.c:178 [inline] > fixup_bug arch/x86/kernel/traps.c:173 [inline] > do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 > do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290 > invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 > RIP: 0010:cred_label security/apparmor/include/cred.h:30 [inline] > RIP: 0010:apparmor_cred_free+0x12f/0x1a0 security/apparmor/lsm.c:62 > Code: 7c 88 48 c7 c7 00 d0 7c 88 e8 fd 70 f2 fd 0f 0b eb a9 e8 54 3f 29 fe 48 > c7 c6 c0 df 7c 88 48 c7 c7 00 d0 7c 88 e8 e1 70 f2 fd <0f> 0b 48 b8 00 00 00 > 00 00 fc ff df 80 38 00 75 4a 4c 8b 2c 25 00 > RSP: 0018:8880ae6079f8 EFLAGS: 00010286 > RAX: RBX: RCX: > RDX: 0100 RSI: 81687fa6 RDI: 0006 > RBP: 8880ae607a18 R08: 8987dec0 R09: > R10: R11: R12: 8880a86b3100 > R13: 8880a86b3100 R14: 8880a86b3188 R15: dc00 > security_cred_free+0x4b/0xf0 security/security.c:1490 The obvious thing to do is put a check in security_cred_free for a NULL cred->security, in which case the LSM hooks wouldn't get called. It's not clear to me how we got a cred that doesn't have an allocated security blob. > put_cred_rcu+0x21f/0x6e0 kernel/cred.c:118 > __rcu_reclaim kernel/rcu/rcu.h:240 [inline] > rcu_do_batch kernel/rcu/tree.c:2486 [inline] > invoke_rcu_callbacks kernel/rcu/tree.c:2799 [inline] > rcu_core+0xc4a/0x1680 kernel/rcu/tree.c:2780 > __do_softirq+0x30b/0xb11 kernel/softirq.c:292 > invoke_softirq kernel/softirq.c:373 [inline] > irq_exit+0x180/0x1d0 kernel/softirq.c:413 > exiting_irq arch/x86/include/asm/apic.h:536 [inline] > smp_apic_timer_interrupt+0x1b7/0x760 arch/x86/kernel/apic/apic.c:1062 > apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 > > RIP: 0010:native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:58 > Code: ff ff ff 48 89 c7 48 89 45 d8 e8 79 6f d0 f9 48 8b 45 d8 e9 ce fe ff ff > 48 89 df e8 68 6f d0 f9 eb 82 90 90 90 90 90 90 fb f4 0f 1f 00 66 2e 0f > 1f 84 00 00 00 00 00 f4 c3 90 90 90 90 90 90 > RSP: 0018:89807c60 EFLAGS: 0282 ORIG_RAX: ff13 > RAX: 11325061 RBX: 11300f8f RCX: > RDX: dc00 RSI: 0001 RDI: 8987e73c > RBP: 89807d20 R08: 8987dec0 R09: > R10: R11: R12: > R13: 89807cf8 R14: R15: 899282f8 > arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:555 > default_idle_call+0x36/0x90 kernel/sched/idle.c:93 > cpuidle_idle_call kernel/sched/idle.c:153 [inline] > do_idle+0x386/0x5d0 kernel/sched/idle.c:262 > cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:353 > rest_init+0x245/0x37b init/main.c:442 > arch_call_rest_init+0xe/0x1b > start_kernel+0x882/0x8bd init/main.c:742 > x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470 > x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:451 > secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 > Kernel Offset: disabled > Rebooting in 86400 seconds.. > > > --- > 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 syzkal...@googlegroups.com. > > syzbot will keep track of this bug report. See: > ht
WARNING in apparmor_cred_free
Hello, syzbot found the following crash on: HEAD commit:b808822a75a3 Add linux-next specific files for 20190111 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=179c22f740 kernel config: https://syzkaller.appspot.com/x/.config?x=c052ead0aed5001b dashboard link: https://syzkaller.appspot.com/bug?extid=69ca07954461f189e808 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=162d947f40 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=139f6c3740 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+69ca07954461f189e...@syzkaller.appspotmail.com [ cut here ] AppArmor WARN cred_label: ((!blob)): WARNING: CPU: 0 PID: 0 at security/apparmor/include/cred.h:30 cred_label security/apparmor/include/cred.h:30 [inline] WARNING: CPU: 0 PID: 0 at security/apparmor/include/cred.h:30 apparmor_cred_free+0x12f/0x1a0 security/apparmor/lsm.c:62 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.0.0-rc1-next-20190111 #10 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 panic+0x2cb/0x65c kernel/panic.c:214 __warn.cold+0x20/0x48 kernel/panic.c:571 report_bug+0x263/0x2b0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] fixup_bug arch/x86/kernel/traps.c:173 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 RIP: 0010:cred_label security/apparmor/include/cred.h:30 [inline] RIP: 0010:apparmor_cred_free+0x12f/0x1a0 security/apparmor/lsm.c:62 Code: 7c 88 48 c7 c7 00 d0 7c 88 e8 fd 70 f2 fd 0f 0b eb a9 e8 54 3f 29 fe 48 c7 c6 c0 df 7c 88 48 c7 c7 00 d0 7c 88 e8 e1 70 f2 fd <0f> 0b 48 b8 00 00 00 00 00 fc ff df 80 38 00 75 4a 4c 8b 2c 25 00 RSP: 0018:8880ae6079f8 EFLAGS: 00010286 RAX: RBX: RCX: RDX: 0100 RSI: 81687fa6 RDI: 0006 RBP: 8880ae607a18 R08: 8987dec0 R09: R10: R11: R12: 8880a86b3100 R13: 8880a86b3100 R14: 8880a86b3188 R15: dc00 security_cred_free+0x4b/0xf0 security/security.c:1490 put_cred_rcu+0x21f/0x6e0 kernel/cred.c:118 __rcu_reclaim kernel/rcu/rcu.h:240 [inline] rcu_do_batch kernel/rcu/tree.c:2486 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2799 [inline] rcu_core+0xc4a/0x1680 kernel/rcu/tree.c:2780 __do_softirq+0x30b/0xb11 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1b7/0x760 arch/x86/kernel/apic/apic.c:1062 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 RIP: 0010:native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:58 Code: ff ff ff 48 89 c7 48 89 45 d8 e8 79 6f d0 f9 48 8b 45 d8 e9 ce fe ff ff 48 89 df e8 68 6f d0 f9 eb 82 90 90 90 90 90 90 fb f4 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 f4 c3 90 90 90 90 90 90 RSP: 0018:89807c60 EFLAGS: 0282 ORIG_RAX: ff13 RAX: 11325061 RBX: 11300f8f RCX: RDX: dc00 RSI: 0001 RDI: 8987e73c RBP: 89807d20 R08: 8987dec0 R09: R10: R11: R12: R13: 89807cf8 R14: R15: 899282f8 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:555 default_idle_call+0x36/0x90 kernel/sched/idle.c:93 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x386/0x5d0 kernel/sched/idle.c:262 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:353 rest_init+0x245/0x37b init/main.c:442 arch_call_rest_init+0xe/0x1b start_kernel+0x882/0x8bd init/main.c:742 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:451 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 Kernel Offset: disabled Rebooting in 86400 seconds.. --- 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 syzkal...@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot. syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches
