Re: [PATCH v2] q800: fix segfault with invalid MacROM
On 07/01/2022 10:50, Laurent Vivier wrote: "qemu-system-m68k -M q800 -bios /dev/null" crashes with a segfault in q800_init(). This happens because the code doesn't check that rom_ptr() returned a non-NULL pointer . To avoid NULL pointer, don't allow 0 sized file and use bios_size with rom_ptr(). Resolves: https://gitlab.com/qemu-project/qemu/-/issues/756 Reported-by: Peter Maydell Signed-off-by: Laurent Vivier --- hw/m68k/q800.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/hw/m68k/q800.c b/hw/m68k/q800.c index e4c7c9b88ad0..55dfe5036f40 100644 --- a/hw/m68k/q800.c +++ b/hw/m68k/q800.c @@ -672,12 +672,13 @@ static void q800_init(MachineState *machine) /* Remove qtest_enabled() check once firmware files are in the tree */ if (!qtest_enabled()) { -if (bios_size < 0 || bios_size > MACROM_SIZE) { +if (bios_size <= 0 || bios_size > MACROM_SIZE) { error_report("could not load MacROM '%s'", bios_name); exit(1); } -ptr = rom_ptr(MACROM_ADDR, MACROM_SIZE); +ptr = rom_ptr(MACROM_ADDR, bios_size); +assert(ptr != NULL); stl_phys(cs->as, 0, ldl_p(ptr));/* reset initial SP */ stl_phys(cs->as, 4, MACROM_ADDR + ldl_p(ptr + 4)); /* reset initial PC */ I think technically the second parameter of rom_ptr() is supposed to be the absolute upper bound of the accessible region so the existing MACROM_SIZE feels better being a constant rather than a variable such as bios_size. But then again bios_size should never be greater than MACROM_SIZE because of the check beforehand so it shouldn't matter in practice. Anyhow regardless of what you decide: Reviewed-by: Mark Cave-Ayland ATB, Mark.
Re: [PATCH v2] q800: fix segfault with invalid MacROM
On 07/01/2022 11.50, Laurent Vivier wrote: "qemu-system-m68k -M q800 -bios /dev/null" crashes with a segfault in q800_init(). This happens because the code doesn't check that rom_ptr() returned a non-NULL pointer . To avoid NULL pointer, don't allow 0 sized file and use bios_size with rom_ptr(). Resolves: https://gitlab.com/qemu-project/qemu/-/issues/756 Reported-by: Peter Maydell Signed-off-by: Laurent Vivier --- hw/m68k/q800.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/hw/m68k/q800.c b/hw/m68k/q800.c index e4c7c9b88ad0..55dfe5036f40 100644 --- a/hw/m68k/q800.c +++ b/hw/m68k/q800.c @@ -672,12 +672,13 @@ static void q800_init(MachineState *machine) /* Remove qtest_enabled() check once firmware files are in the tree */ if (!qtest_enabled()) { -if (bios_size < 0 || bios_size > MACROM_SIZE) { +if (bios_size <= 0 || bios_size > MACROM_SIZE) { error_report("could not load MacROM '%s'", bios_name); exit(1); } -ptr = rom_ptr(MACROM_ADDR, MACROM_SIZE); +ptr = rom_ptr(MACROM_ADDR, bios_size); +assert(ptr != NULL); stl_phys(cs->as, 0, ldl_p(ptr));/* reset initial SP */ stl_phys(cs->as, 4, MACROM_ADDR + ldl_p(ptr + 4)); /* reset initial PC */ Looks nicer than v1, indeed. Reviewed-by: Thomas Huth
[PATCH v2] q800: fix segfault with invalid MacROM
"qemu-system-m68k -M q800 -bios /dev/null" crashes with a segfault in q800_init(). This happens because the code doesn't check that rom_ptr() returned a non-NULL pointer . To avoid NULL pointer, don't allow 0 sized file and use bios_size with rom_ptr(). Resolves: https://gitlab.com/qemu-project/qemu/-/issues/756 Reported-by: Peter Maydell Signed-off-by: Laurent Vivier --- hw/m68k/q800.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/hw/m68k/q800.c b/hw/m68k/q800.c index e4c7c9b88ad0..55dfe5036f40 100644 --- a/hw/m68k/q800.c +++ b/hw/m68k/q800.c @@ -672,12 +672,13 @@ static void q800_init(MachineState *machine) /* Remove qtest_enabled() check once firmware files are in the tree */ if (!qtest_enabled()) { -if (bios_size < 0 || bios_size > MACROM_SIZE) { +if (bios_size <= 0 || bios_size > MACROM_SIZE) { error_report("could not load MacROM '%s'", bios_name); exit(1); } -ptr = rom_ptr(MACROM_ADDR, MACROM_SIZE); +ptr = rom_ptr(MACROM_ADDR, bios_size); +assert(ptr != NULL); stl_phys(cs->as, 0, ldl_p(ptr));/* reset initial SP */ stl_phys(cs->as, 4, MACROM_ADDR + ldl_p(ptr + 4)); /* reset initial PC */ -- 2.33.1