* [PATCH] riscv: reject invalid syscalls below -1
@ 2019-12-18 8:47 David Abdurachmanov
2019-12-18 9:46 ` Andreas Schwab
2019-12-28 6:02 ` Paul Walmsley
0 siblings, 2 replies; 5+ messages in thread
From: David Abdurachmanov @ 2019-12-18 8:47 UTC (permalink / raw)
To: Paul Walmsley, Palmer Dabbelt, Albert Ou, David Abdurachmanov,
Kees Cook, Anup Patel, Vincent Chen, Valentin Schneider,
Thomas Gleixner, Bin Meng, linux-riscv, linux-kernel
Cc: david.abdurachmanov
Running "stress-ng --enosys 4 -t 20 -v" showed a large number of kernel oops
with "Unable to handle kernel paging request at virtual address" message. This
happens when enosys stressor starts testing random non-valid syscalls.
I forgot to redirect any syscall below -1 to sys_ni_syscall.
With the patch kernel oops messages are gone while running stress-ng enosys
stressor.
Signed-off-by: David Abdurachmanov <david.abdurachmanov@sifive.com>
Fixes: 5340627e3fe0 ("riscv: add support for SECCOMP and SECCOMP_FILTER")
---
arch/riscv/kernel/entry.S | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index a1349ca64669..e163b7b64c86 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -246,6 +246,7 @@ check_syscall_nr:
*/
li t1, -1
beq a7, t1, ret_from_syscall_rejected
+ blt a7, t1, 1f
/* Call syscall */
la s0, sys_call_table
slli t0, a7, RISCV_LGPTR
--
2.24.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] riscv: reject invalid syscalls below -1
2019-12-18 8:47 [PATCH] riscv: reject invalid syscalls below -1 David Abdurachmanov
@ 2019-12-18 9:46 ` Andreas Schwab
2019-12-18 10:06 ` David Abdurachmanov
2019-12-28 6:02 ` Paul Walmsley
1 sibling, 1 reply; 5+ messages in thread
From: Andreas Schwab @ 2019-12-18 9:46 UTC (permalink / raw)
To: David Abdurachmanov
Cc: Paul Walmsley, Palmer Dabbelt, Albert Ou, David Abdurachmanov,
Kees Cook, Anup Patel, Vincent Chen, Valentin Schneider,
Thomas Gleixner, Bin Meng, linux-riscv, linux-kernel
On Dez 18 2019, David Abdurachmanov wrote:
> diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
> index a1349ca64669..e163b7b64c86 100644
> --- a/arch/riscv/kernel/entry.S
> +++ b/arch/riscv/kernel/entry.S
> @@ -246,6 +246,7 @@ check_syscall_nr:
> */
> li t1, -1
> beq a7, t1, ret_from_syscall_rejected
> + blt a7, t1, 1f
How about using bgeu instead in the preceding check?
/*
* Syscall number held in a7.
* If syscall number is above allowed value, redirect to ni_syscall.
*/
bge a7, t0, 1f
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] riscv: reject invalid syscalls below -1
2019-12-18 9:46 ` Andreas Schwab
@ 2019-12-18 10:06 ` David Abdurachmanov
2019-12-18 10:35 ` Andreas Schwab
0 siblings, 1 reply; 5+ messages in thread
From: David Abdurachmanov @ 2019-12-18 10:06 UTC (permalink / raw)
To: Andreas Schwab
Cc: Paul Walmsley, Palmer Dabbelt, Albert Ou, David Abdurachmanov,
Kees Cook, Anup Patel, Vincent Chen, Valentin Schneider,
Thomas Gleixner, Bin Meng, linux-riscv,
linux-kernel@vger.kernel.org List
On Wed, Dec 18, 2019 at 11:46 AM Andreas Schwab <schwab@suse.de> wrote:
>
> On Dez 18 2019, David Abdurachmanov wrote:
>
> > diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
> > index a1349ca64669..e163b7b64c86 100644
> > --- a/arch/riscv/kernel/entry.S
> > +++ b/arch/riscv/kernel/entry.S
> > @@ -246,6 +246,7 @@ check_syscall_nr:
> > */
> > li t1, -1
> > beq a7, t1, ret_from_syscall_rejected
> > + blt a7, t1, 1f
>
> How about using bgeu instead in the preceding check?
The syscall number could be -1 if tracer rejected it.
We could do:
li t0, __NR_syscalls
[..]
// first check if syscall was rejected
li t1, -1
beq a7, t1, ret_from_syscall_rejected
// then check the bounds
bgeu a7, t0, 1f
>
> /*
> * Syscall number held in a7.
> * If syscall number is above allowed value, redirect to ni_syscall.
> */
> bge a7, t0, 1f
>
> Andreas.
>
> --
> Andreas Schwab, SUSE Labs, schwab@suse.de
> GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
> "And now for something completely different."
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] riscv: reject invalid syscalls below -1
2019-12-18 10:06 ` David Abdurachmanov
@ 2019-12-18 10:35 ` Andreas Schwab
0 siblings, 0 replies; 5+ messages in thread
From: Andreas Schwab @ 2019-12-18 10:35 UTC (permalink / raw)
To: David Abdurachmanov
Cc: Paul Walmsley, Palmer Dabbelt, Albert Ou, David Abdurachmanov,
Kees Cook, Anup Patel, Vincent Chen, Valentin Schneider,
Thomas Gleixner, Bin Meng, linux-riscv,
linux-kernel@vger.kernel.org List
On Dez 18 2019, David Abdurachmanov wrote:
> On Wed, Dec 18, 2019 at 11:46 AM Andreas Schwab <schwab@suse.de> wrote:
>>
>> On Dez 18 2019, David Abdurachmanov wrote:
>>
>> > diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
>> > index a1349ca64669..e163b7b64c86 100644
>> > --- a/arch/riscv/kernel/entry.S
>> > +++ b/arch/riscv/kernel/entry.S
>> > @@ -246,6 +246,7 @@ check_syscall_nr:
>> > */
>> > li t1, -1
>> > beq a7, t1, ret_from_syscall_rejected
>> > + blt a7, t1, 1f
>>
>> How about using bgeu instead in the preceding check?
>
> The syscall number could be -1 if tracer rejected it.
So check for -1 first, then for out-of-range?
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] riscv: reject invalid syscalls below -1
2019-12-18 8:47 [PATCH] riscv: reject invalid syscalls below -1 David Abdurachmanov
2019-12-18 9:46 ` Andreas Schwab
@ 2019-12-28 6:02 ` Paul Walmsley
1 sibling, 0 replies; 5+ messages in thread
From: Paul Walmsley @ 2019-12-28 6:02 UTC (permalink / raw)
To: David Abdurachmanov
Cc: Palmer Dabbelt, Albert Ou, David Abdurachmanov, Kees Cook,
Anup Patel, Vincent Chen, Valentin Schneider, Thomas Gleixner,
Bin Meng, linux-riscv, linux-kernel
On Wed, 18 Dec 2019, David Abdurachmanov wrote:
> Running "stress-ng --enosys 4 -t 20 -v" showed a large number of kernel oops
> with "Unable to handle kernel paging request at virtual address" message. This
> happens when enosys stressor starts testing random non-valid syscalls.
>
> I forgot to redirect any syscall below -1 to sys_ni_syscall.
>
> With the patch kernel oops messages are gone while running stress-ng enosys
> stressor.
>
> Signed-off-by: David Abdurachmanov <david.abdurachmanov@sifive.com>
> Fixes: 5340627e3fe0 ("riscv: add support for SECCOMP and SECCOMP_FILTER")
From the thread, I couldn't tell whether you were happy with this patch as
it stands or not; the thread seems to have petered out. So this one has
been queued for v5.5-rc; let me know if you didn't intend for that to
happen.
- Paul
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2019-12-28 6:03 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2019-12-18 8:47 [PATCH] riscv: reject invalid syscalls below -1 David Abdurachmanov
2019-12-18 9:46 ` Andreas Schwab
2019-12-18 10:06 ` David Abdurachmanov
2019-12-18 10:35 ` Andreas Schwab
2019-12-28 6:02 ` Paul Walmsley
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