Commit 1669add7 authored Dec 22, 2014 by Peter Maydell Committed by Riku Voipio Jan 27, 2015

linux-user: Fix broken m68k signal handling on 64 bit hosts



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>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>

parent ec355f15

linux-user/signal.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -5066,7 +5066,7 @@ 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 */

		@@ -5200,8 +5200,8 @@ 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;