* [PATCH] capabilities: fix undefined behavior in bit shift for CAP_TO_MASK
@ 2022-10-31 11:25 Gaosheng Cui
2022-10-31 14:18 ` Andrew G. Morgan
2022-11-05 5:30 ` Paul Moore
0 siblings, 2 replies; 7+ messages in thread
From: Gaosheng Cui @ 2022-10-31 11:25 UTC (permalink / raw)
To: serge, morgan, akpm, ezk, cuigaosheng1; +Cc: linux-security-module
Shifting signed 32-bit value by 31 bits is undefined, so changing
significant bit to unsigned. The UBSAN warning calltrace like below:
UBSAN: shift-out-of-bounds in security/commoncap.c:1252:2
left shift of 1 by 31 places cannot be represented in type 'int'
Call Trace:
<TASK>
dump_stack_lvl+0x7d/0xa5
dump_stack+0x15/0x1b
ubsan_epilogue+0xe/0x4e
__ubsan_handle_shift_out_of_bounds+0x1e7/0x20c
cap_task_prctl+0x561/0x6f0
security_task_prctl+0x5a/0xb0
__x64_sys_prctl+0x61/0x8f0
do_syscall_64+0x58/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
</TASK>
Fixes: e338d263a76a ("Add 64-bit capability support to the kernel")
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
---
include/uapi/linux/capability.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/uapi/linux/capability.h b/include/uapi/linux/capability.h
index 463d1ba2232a..3d61a0ae055d 100644
--- a/include/uapi/linux/capability.h
+++ b/include/uapi/linux/capability.h
@@ -426,7 +426,7 @@ struct vfs_ns_cap_data {
*/
#define CAP_TO_INDEX(x) ((x) >> 5) /* 1 << 5 == bits in __u32 */
-#define CAP_TO_MASK(x) (1 << ((x) & 31)) /* mask for indexed __u32 */
+#define CAP_TO_MASK(x) (1U << ((x) & 31)) /* mask for indexed __u32 */
#endif /* _UAPI_LINUX_CAPABILITY_H */
--
2.25.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] capabilities: fix undefined behavior in bit shift for CAP_TO_MASK
2022-10-31 11:25 [PATCH] capabilities: fix undefined behavior in bit shift for CAP_TO_MASK Gaosheng Cui
@ 2022-10-31 14:18 ` Andrew G. Morgan
2022-11-01 4:30 ` Serge E. Hallyn
2022-11-05 5:30 ` Paul Moore
1 sibling, 1 reply; 7+ messages in thread
From: Andrew G. Morgan @ 2022-10-31 14:18 UTC (permalink / raw)
To: Gaosheng Cui; +Cc: serge, akpm, ezk, linux-security-module
Acked-by: Andrew G. Morgan <morgan@kernel.org>
On Mon, Oct 31, 2022 at 4:25 AM Gaosheng Cui <cuigaosheng1@huawei.com> wrote:
>
> Shifting signed 32-bit value by 31 bits is undefined, so changing
> significant bit to unsigned. The UBSAN warning calltrace like below:
>
> UBSAN: shift-out-of-bounds in security/commoncap.c:1252:2
> left shift of 1 by 31 places cannot be represented in type 'int'
> Call Trace:
> <TASK>
> dump_stack_lvl+0x7d/0xa5
> dump_stack+0x15/0x1b
> ubsan_epilogue+0xe/0x4e
> __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c
> cap_task_prctl+0x561/0x6f0
> security_task_prctl+0x5a/0xb0
> __x64_sys_prctl+0x61/0x8f0
> do_syscall_64+0x58/0x80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
> </TASK>
>
> Fixes: e338d263a76a ("Add 64-bit capability support to the kernel")
> Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
> ---
> include/uapi/linux/capability.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/uapi/linux/capability.h b/include/uapi/linux/capability.h
> index 463d1ba2232a..3d61a0ae055d 100644
> --- a/include/uapi/linux/capability.h
> +++ b/include/uapi/linux/capability.h
> @@ -426,7 +426,7 @@ struct vfs_ns_cap_data {
> */
>
> #define CAP_TO_INDEX(x) ((x) >> 5) /* 1 << 5 == bits in __u32 */
> -#define CAP_TO_MASK(x) (1 << ((x) & 31)) /* mask for indexed __u32 */
> +#define CAP_TO_MASK(x) (1U << ((x) & 31)) /* mask for indexed __u32 */
>
>
> #endif /* _UAPI_LINUX_CAPABILITY_H */
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] capabilities: fix undefined behavior in bit shift for CAP_TO_MASK
2022-10-31 14:18 ` Andrew G. Morgan
@ 2022-11-01 4:30 ` Serge E. Hallyn
2022-11-03 11:57 ` Paul Moore
0 siblings, 1 reply; 7+ messages in thread
From: Serge E. Hallyn @ 2022-11-01 4:30 UTC (permalink / raw)
To: Andrew G. Morgan; +Cc: Gaosheng Cui, serge, akpm, ezk, linux-security-module
On Mon, Oct 31, 2022 at 07:18:54AM -0700, Andrew G. Morgan wrote:
> Acked-by: Andrew G. Morgan <morgan@kernel.org>
>
>
> On Mon, Oct 31, 2022 at 4:25 AM Gaosheng Cui <cuigaosheng1@huawei.com> wrote:
> >
> > Shifting signed 32-bit value by 31 bits is undefined, so changing
> > significant bit to unsigned. The UBSAN warning calltrace like below:
> >
> > UBSAN: shift-out-of-bounds in security/commoncap.c:1252:2
> > left shift of 1 by 31 places cannot be represented in type 'int'
> > Call Trace:
> > <TASK>
> > dump_stack_lvl+0x7d/0xa5
> > dump_stack+0x15/0x1b
> > ubsan_epilogue+0xe/0x4e
> > __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c
> > cap_task_prctl+0x561/0x6f0
> > security_task_prctl+0x5a/0xb0
> > __x64_sys_prctl+0x61/0x8f0
> > do_syscall_64+0x58/0x80
> > entry_SYSCALL_64_after_hwframe+0x63/0xcd
> > </TASK>
> >
> > Fixes: e338d263a76a ("Add 64-bit capability support to the kernel")
> > Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Paul, do you mind including this in your lsm tree?
thanks,
-serge
> > ---
> > include/uapi/linux/capability.h | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/uapi/linux/capability.h b/include/uapi/linux/capability.h
> > index 463d1ba2232a..3d61a0ae055d 100644
> > --- a/include/uapi/linux/capability.h
> > +++ b/include/uapi/linux/capability.h
> > @@ -426,7 +426,7 @@ struct vfs_ns_cap_data {
> > */
> >
> > #define CAP_TO_INDEX(x) ((x) >> 5) /* 1 << 5 == bits in __u32 */
> > -#define CAP_TO_MASK(x) (1 << ((x) & 31)) /* mask for indexed __u32 */
> > +#define CAP_TO_MASK(x) (1U << ((x) & 31)) /* mask for indexed __u32 */
> >
> >
> > #endif /* _UAPI_LINUX_CAPABILITY_H */
> > --
> > 2.25.1
> >
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] capabilities: fix undefined behavior in bit shift for CAP_TO_MASK
2022-11-01 4:30 ` Serge E. Hallyn
@ 2022-11-03 11:57 ` Paul Moore
2022-11-03 13:24 ` Serge E. Hallyn
0 siblings, 1 reply; 7+ messages in thread
From: Paul Moore @ 2022-11-03 11:57 UTC (permalink / raw)
To: Serge E. Hallyn
Cc: Andrew G. Morgan, Gaosheng Cui, akpm, ezk, linux-security-module
On Tue, Nov 1, 2022 at 12:30 AM Serge E. Hallyn <serge@hallyn.com> wrote:
> On Mon, Oct 31, 2022 at 07:18:54AM -0700, Andrew G. Morgan wrote:
> > Acked-by: Andrew G. Morgan <morgan@kernel.org>
> >
> >
> > On Mon, Oct 31, 2022 at 4:25 AM Gaosheng Cui <cuigaosheng1@huawei.com> wrote:
> > >
> > > Shifting signed 32-bit value by 31 bits is undefined, so changing
> > > significant bit to unsigned. The UBSAN warning calltrace like below:
> > >
> > > UBSAN: shift-out-of-bounds in security/commoncap.c:1252:2
> > > left shift of 1 by 31 places cannot be represented in type 'int'
> > > Call Trace:
> > > <TASK>
> > > dump_stack_lvl+0x7d/0xa5
> > > dump_stack+0x15/0x1b
> > > ubsan_epilogue+0xe/0x4e
> > > __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c
> > > cap_task_prctl+0x561/0x6f0
> > > security_task_prctl+0x5a/0xb0
> > > __x64_sys_prctl+0x61/0x8f0
> > > do_syscall_64+0x58/0x80
> > > entry_SYSCALL_64_after_hwframe+0x63/0xcd
> > > </TASK>
> > >
> > > Fixes: e338d263a76a ("Add 64-bit capability support to the kernel")
> > > Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
>
> Reviewed-by: Serge Hallyn <serge@hallyn.com>
>
> Paul, do you mind including this in your lsm tree?
Sure, although just a warning that it might not happen until next
week. Maybe I'll get some time this weekend but I can't be certain.
> > > ---
> > > include/uapi/linux/capability.h | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/include/uapi/linux/capability.h b/include/uapi/linux/capability.h
> > > index 463d1ba2232a..3d61a0ae055d 100644
> > > --- a/include/uapi/linux/capability.h
> > > +++ b/include/uapi/linux/capability.h
> > > @@ -426,7 +426,7 @@ struct vfs_ns_cap_data {
> > > */
> > >
> > > #define CAP_TO_INDEX(x) ((x) >> 5) /* 1 << 5 == bits in __u32 */
> > > -#define CAP_TO_MASK(x) (1 << ((x) & 31)) /* mask for indexed __u32 */
> > > +#define CAP_TO_MASK(x) (1U << ((x) & 31)) /* mask for indexed __u32 */
> > >
> > >
> > > #endif /* _UAPI_LINUX_CAPABILITY_H */
> > > --
> > > 2.25.1
--
paul-moore.com
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] capabilities: fix undefined behavior in bit shift for CAP_TO_MASK
2022-11-03 11:57 ` Paul Moore
@ 2022-11-03 13:24 ` Serge E. Hallyn
2022-11-05 5:33 ` Paul Moore
0 siblings, 1 reply; 7+ messages in thread
From: Serge E. Hallyn @ 2022-11-03 13:24 UTC (permalink / raw)
To: Paul Moore
Cc: Serge E. Hallyn, Andrew G. Morgan, Gaosheng Cui, akpm, ezk,
linux-security-module
On Thu, Nov 03, 2022 at 07:57:45AM -0400, Paul Moore wrote:
> On Tue, Nov 1, 2022 at 12:30 AM Serge E. Hallyn <serge@hallyn.com> wrote:
> > On Mon, Oct 31, 2022 at 07:18:54AM -0700, Andrew G. Morgan wrote:
> > > Acked-by: Andrew G. Morgan <morgan@kernel.org>
> > >
> > >
> > > On Mon, Oct 31, 2022 at 4:25 AM Gaosheng Cui <cuigaosheng1@huawei.com> wrote:
> > > >
> > > > Shifting signed 32-bit value by 31 bits is undefined, so changing
> > > > significant bit to unsigned. The UBSAN warning calltrace like below:
> > > >
> > > > UBSAN: shift-out-of-bounds in security/commoncap.c:1252:2
> > > > left shift of 1 by 31 places cannot be represented in type 'int'
> > > > Call Trace:
> > > > <TASK>
> > > > dump_stack_lvl+0x7d/0xa5
> > > > dump_stack+0x15/0x1b
> > > > ubsan_epilogue+0xe/0x4e
> > > > __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c
> > > > cap_task_prctl+0x561/0x6f0
> > > > security_task_prctl+0x5a/0xb0
> > > > __x64_sys_prctl+0x61/0x8f0
> > > > do_syscall_64+0x58/0x80
> > > > entry_SYSCALL_64_after_hwframe+0x63/0xcd
> > > > </TASK>
> > > >
> > > > Fixes: e338d263a76a ("Add 64-bit capability support to the kernel")
> > > > Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
> >
> > Reviewed-by: Serge Hallyn <serge@hallyn.com>
> >
> > Paul, do you mind including this in your lsm tree?
>
> Sure, although just a warning that it might not happen until next
> week. Maybe I'll get some time this weekend but I can't be certain.
Ok, thanks.
I wouldn't mind putting up a capability tree if number of patches were
going to start ramping up, but historically that has not been worth it.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] capabilities: fix undefined behavior in bit shift for CAP_TO_MASK
2022-10-31 11:25 [PATCH] capabilities: fix undefined behavior in bit shift for CAP_TO_MASK Gaosheng Cui
2022-10-31 14:18 ` Andrew G. Morgan
@ 2022-11-05 5:30 ` Paul Moore
1 sibling, 0 replies; 7+ messages in thread
From: Paul Moore @ 2022-11-05 5:30 UTC (permalink / raw)
To: Gaosheng Cui; +Cc: serge, morgan, akpm, ezk, linux-security-module
On Mon, Oct 31, 2022 at 7:25 AM Gaosheng Cui <cuigaosheng1@huawei.com> wrote:
>
> Shifting signed 32-bit value by 31 bits is undefined, so changing
> significant bit to unsigned. The UBSAN warning calltrace like below:
>
> UBSAN: shift-out-of-bounds in security/commoncap.c:1252:2
> left shift of 1 by 31 places cannot be represented in type 'int'
> Call Trace:
> <TASK>
> dump_stack_lvl+0x7d/0xa5
> dump_stack+0x15/0x1b
> ubsan_epilogue+0xe/0x4e
> __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c
> cap_task_prctl+0x561/0x6f0
> security_task_prctl+0x5a/0xb0
> __x64_sys_prctl+0x61/0x8f0
> do_syscall_64+0x58/0x80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
> </TASK>
>
> Fixes: e338d263a76a ("Add 64-bit capability support to the kernel")
> Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
> ---
> include/uapi/linux/capability.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Merged into lsm/stable-6.1, and I'll plan to send this up to Linus
next week. Thanks everyone!
--
paul-moore.com
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] capabilities: fix undefined behavior in bit shift for CAP_TO_MASK
2022-11-03 13:24 ` Serge E. Hallyn
@ 2022-11-05 5:33 ` Paul Moore
0 siblings, 0 replies; 7+ messages in thread
From: Paul Moore @ 2022-11-05 5:33 UTC (permalink / raw)
To: Serge E. Hallyn
Cc: Andrew G. Morgan, Gaosheng Cui, akpm, ezk, linux-security-module
On Thu, Nov 3, 2022 at 9:24 AM Serge E. Hallyn <serge@hallyn.com> wrote:
> Ok, thanks.
>
> I wouldn't mind putting up a capability tree if number of patches were
> going to start ramping up, but historically that has not been worth it.
Don't ever let me stop you from setting up a capability tree, but
yeah, I understand why it probably wouldn't be very useful. As long
as you keep doing the reviews, ACKs, etc. I don't mind carrying the
capability patches in the LSM tree; merging stuff is usually the easy
part of the job.
--
paul-moore.com
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2022-11-05 5:33 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-10-31 11:25 [PATCH] capabilities: fix undefined behavior in bit shift for CAP_TO_MASK Gaosheng Cui
2022-10-31 14:18 ` Andrew G. Morgan
2022-11-01 4:30 ` Serge E. Hallyn
2022-11-03 11:57 ` Paul Moore
2022-11-03 13:24 ` Serge E. Hallyn
2022-11-05 5:33 ` Paul Moore
2022-11-05 5:30 ` Paul Moore
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