[PATCH] hw/gpio: npcm7xx: fixup out-of-bounds access

[PATCH] hw/gpio: npcm7xx: fixup out-of-bounds access

[Patrick Venture]

The reg isn't validated to be a possible register before
it's dereferenced for one case.  The mmio space registered
for the gpio device is 4KiB but there aren't that many
registers in the struct.

Google-Bug-Id: 397469048
Change-Id: I2fb8d0d3d41422baab22e8fc7e9fadd0f2ee7068
Signed-off-by: Patrick Venture <venture@google.com>
---
 hw/gpio/npcm7xx_gpio.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/hw/gpio/npcm7xx_gpio.c b/hw/gpio/npcm7xx_gpio.c
index 23e67424c9..2916056fae 100644
--- a/hw/gpio/npcm7xx_gpio.c
+++ b/hw/gpio/npcm7xx_gpio.c
@@ -220,8 +220,6 @@ static void npcm7xx_gpio_regs_write(void *opaque, hwaddr addr, uint64_t v,
         return;
     }
 
-    diff = s->regs[reg] ^ value;
-
     switch (reg) {
     case NPCM7XX_GPIO_TLOCK1:
     case NPCM7XX_GPIO_TLOCK2:
@@ -242,6 +240,7 @@ static void npcm7xx_gpio_regs_write(void *opaque, hwaddr addr, uint64_t v,
     case NPCM7XX_GPIO_PU:
     case NPCM7XX_GPIO_PD:
     case NPCM7XX_GPIO_IEM:
+        diff = s->regs[reg] ^ value;
         s->regs[reg] = value;
         npcm7xx_gpio_update_pins(s, diff);
         break;
-- 
2.48.1.658.g4767266eb4-goog

Re: [PATCH] hw/gpio: npcm7xx: fixup out-of-bounds access

[Philippe Mathieu-Daudé]

On 26/2/25 03:46, Patrick Venture wrote:
> The reg isn't validated to be a possible register before
> it's dereferenced for one case.  The mmio space registered
> for the gpio device is 4KiB but there aren't that many
> registers in the struct.
> 
> Google-Bug-Id: 397469048
> Change-Id: I2fb8d0d3d41422baab22e8fc7e9fadd0f2ee7068

^ Both lines are irrelevant on mainstream git history, otherwise:

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

Cc: qemu-stable@nongnu.org
Fixes: 526dbbe0874 ("hw/gpio: Add GPIO model for Nuvoton NPCM7xx")

> Signed-off-by: Patrick Venture <venture@google.com>
> ---
>   hw/gpio/npcm7xx_gpio.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)

Re: [PATCH] hw/gpio: npcm7xx: fixup out-of-bounds access

[Patrick Venture]

[-- Attachment #1: Type: text/plain, Size: 945 bytes --]

On Tue, Feb 25, 2025 at 11:04 PM Philippe Mathieu-Daudé <philmd@linaro.org>
wrote:

> On 26/2/25 03:46, Patrick Venture wrote:
> > The reg isn't validated to be a possible register before
> > it's dereferenced for one case.  The mmio space registered
> > for the gpio device is 4KiB but there aren't that many
> > registers in the struct.
> >
> > Google-Bug-Id: 397469048
> > Change-Id: I2fb8d0d3d41422baab22e8fc7e9fadd0f2ee7068
>
> ^ Both lines are irrelevant on mainstream git history, otherwise:
>

Thanks, sorry, I was in a hurry last night to send this out and forgot to
strip them.


>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>
> Cc: qemu-stable@nongnu.org
> Fixes: 526dbbe0874 ("hw/gpio: Add GPIO model for Nuvoton NPCM7xx")
>
> > Signed-off-by: Patrick Venture <venture@google.com>
> > ---
> >   hw/gpio/npcm7xx_gpio.c | 3 +--
> >   1 file changed, 1 insertion(+), 2 deletions(-)
>
>

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Re: [PATCH] hw/gpio: npcm7xx: fixup out-of-bounds access

[Peter Maydell]

On Wed, 26 Feb 2025 at 02:46, Patrick Venture <venture@google.com> wrote:
>
> The reg isn't validated to be a possible register before
> it's dereferenced for one case.  The mmio space registered
> for the gpio device is 4KiB but there aren't that many
> registers in the struct.
>
> Google-Bug-Id: 397469048
> Change-Id: I2fb8d0d3d41422baab22e8fc7e9fadd0f2ee7068
> Signed-off-by: Patrick Venture <venture@google.com>

Applied to target-arm.next (with commit message tweaks
as per Philippe's email), thanks.

-- PMM