* [Qemu-devel] [PATCH] linux-user: Fix broken m68k signal handling on 64 bit hosts
@ 2014-12-22 17:47 Peter Maydell
2014-12-25 5:10 ` Michael Tokarev
2015-01-26 18:05 ` Peter Maydell
0 siblings, 2 replies; 4+ messages in thread
From: Peter Maydell @ 2014-12-22 17:47 UTC (permalink / raw)
To: qemu-devel; +Cc: Riku Voipio
The m68k signal frame setup code which writes the signal return
trampoline code to the stack was assuming that a 'long' was 32 bits;
on 64 bit systems this meant we would end up writing the 32 bit
(2 insn) trampoline sequence to retaddr+4,retaddr+6 instead of
the intended retaddr+0,retaddr+2, resulting in a guest crash when
it tried to execute the invalid zero-bytes at retaddr+0.
Fix by using uint32_t instead; also use uint16_t rather than short
for consistency. This fixes bug LP:1404690.
Reported-by: Michel Boaventura
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
linux-user/signal.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/linux-user/signal.c b/linux-user/signal.c
index e11b208..a324fd1 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -5091,7 +5091,7 @@ static void setup_frame(int sig, struct target_sigaction *ka,
/* moveq #,d0; trap #0 */
__put_user(0x70004e40 + (TARGET_NR_sigreturn << 16),
- (long *)(frame->retcode));
+ (uint32_t *)(frame->retcode));
/* Set up to return from userspace */
@@ -5225,8 +5225,8 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka,
/* moveq #,d0; notb d0; trap #0 */
__put_user(0x70004600 + ((TARGET_NR_rt_sigreturn ^ 0xff) << 16),
- (long *)(frame->retcode + 0));
- __put_user(0x4e40, (short *)(frame->retcode + 4));
+ (uint32_t *)(frame->retcode + 0));
+ __put_user(0x4e40, (uint16_t *)(frame->retcode + 4));
if (err)
goto give_sigsegv;
--
1.9.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH] linux-user: Fix broken m68k signal handling on 64 bit hosts
2014-12-22 17:47 [Qemu-devel] [PATCH] linux-user: Fix broken m68k signal handling on 64 bit hosts Peter Maydell
@ 2014-12-25 5:10 ` Michael Tokarev
2014-12-25 10:22 ` Peter Maydell
2015-01-26 18:05 ` Peter Maydell
1 sibling, 1 reply; 4+ messages in thread
From: Michael Tokarev @ 2014-12-25 5:10 UTC (permalink / raw)
To: Peter Maydell, qemu-devel; +Cc: Riku Voipio
22.12.2014 20:47, Peter Maydell wrote:
> The m68k signal frame setup code which writes the signal return
> trampoline code to the stack was assuming that a 'long' was 32 bits;
> on 64 bit systems this meant we would end up writing the 32 bit
> (2 insn) trampoline sequence to retaddr+4,retaddr+6 instead of
> the intended retaddr+0,retaddr+2, resulting in a guest crash when
> it tried to execute the invalid zero-bytes at retaddr+0.
> Fix by using uint32_t instead; also use uint16_t rather than short
> for consistency. This fixes bug LP:1404690.
Cc: qemu-stable@ ?
Thanks,
/mjt
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH] linux-user: Fix broken m68k signal handling on 64 bit hosts
2014-12-25 5:10 ` Michael Tokarev
@ 2014-12-25 10:22 ` Peter Maydell
0 siblings, 0 replies; 4+ messages in thread
From: Peter Maydell @ 2014-12-25 10:22 UTC (permalink / raw)
To: Michael Tokarev; +Cc: Riku Voipio, QEMU Developers
On 25 December 2014 at 05:10, Michael Tokarev <mjt@tls.msk.ru> wrote:
> 22.12.2014 20:47, Peter Maydell wrote:
>> The m68k signal frame setup code which writes the signal return
>> trampoline code to the stack was assuming that a 'long' was 32 bits;
>> on 64 bit systems this meant we would end up writing the 32 bit
>> (2 insn) trampoline sequence to retaddr+4,retaddr+6 instead of
>> the intended retaddr+0,retaddr+2, resulting in a guest crash when
>> it tried to execute the invalid zero-bytes at retaddr+0.
>> Fix by using uint32_t instead; also use uint16_t rather than short
>> for consistency. This fixes bug LP:1404690.
>
> Cc: qemu-stable@ ?
Yeah, seems reasonable (though this has been busted for five
years, so I deduce that nobody's actually trying to use it...)
-- PMM
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH] linux-user: Fix broken m68k signal handling on 64 bit hosts
2014-12-22 17:47 [Qemu-devel] [PATCH] linux-user: Fix broken m68k signal handling on 64 bit hosts Peter Maydell
2014-12-25 5:10 ` Michael Tokarev
@ 2015-01-26 18:05 ` Peter Maydell
1 sibling, 0 replies; 4+ messages in thread
From: Peter Maydell @ 2015-01-26 18:05 UTC (permalink / raw)
To: QEMU Developers; +Cc: Riku Voipio
Ping?
thanks
-- PMM
On 22 December 2014 at 17:47, Peter Maydell <peter.maydell@linaro.org> wrote:
> The m68k signal frame setup code which writes the signal return
> trampoline code to the stack was assuming that a 'long' was 32 bits;
> on 64 bit systems this meant we would end up writing the 32 bit
> (2 insn) trampoline sequence to retaddr+4,retaddr+6 instead of
> the intended retaddr+0,retaddr+2, resulting in a guest crash when
> it tried to execute the invalid zero-bytes at retaddr+0.
> Fix by using uint32_t instead; also use uint16_t rather than short
> for consistency. This fixes bug LP:1404690.
>
> Reported-by: Michel Boaventura
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> linux-user/signal.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/linux-user/signal.c b/linux-user/signal.c
> index e11b208..a324fd1 100644
> --- a/linux-user/signal.c
> +++ b/linux-user/signal.c
> @@ -5091,7 +5091,7 @@ static void setup_frame(int sig, struct target_sigaction *ka,
> /* moveq #,d0; trap #0 */
>
> __put_user(0x70004e40 + (TARGET_NR_sigreturn << 16),
> - (long *)(frame->retcode));
> + (uint32_t *)(frame->retcode));
>
> /* Set up to return from userspace */
>
> @@ -5225,8 +5225,8 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka,
> /* moveq #,d0; notb d0; trap #0 */
>
> __put_user(0x70004600 + ((TARGET_NR_rt_sigreturn ^ 0xff) << 16),
> - (long *)(frame->retcode + 0));
> - __put_user(0x4e40, (short *)(frame->retcode + 4));
> + (uint32_t *)(frame->retcode + 0));
> + __put_user(0x4e40, (uint16_t *)(frame->retcode + 4));
>
> if (err)
> goto give_sigsegv;
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2015-01-26 18:05 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2014-12-22 17:47 [Qemu-devel] [PATCH] linux-user: Fix broken m68k signal handling on 64 bit hosts Peter Maydell
2014-12-25 5:10 ` Michael Tokarev
2014-12-25 10:22 ` Peter Maydell
2015-01-26 18:05 ` Peter Maydell
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