| Message ID | 1419270420-10699-1-git-send-email-peter.maydell@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
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
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;
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;
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(-)