Hi Guocai,
On 13/12/24 16:01, guocai.he.cn@xxxxxxxxxxxxx wrote:
From: Ian Ray <ian.ray@xxxxxxxxxxxxxxxx>
[ Upstream commit bfc6444b57dc7186b6acc964705d7516cbaf3904 ]
Ensure that `i2c_lock' is held when setting interrupt latch and mask in
pca953x_irq_bus_sync_unlock() in order to avoid races.
The other (non-probe) call site pca953x_gpio_set_multiple() ensures the
lock is held before calling pca953x_write_regs().
The problem occurred when a request raced against irq_bus_sync_unlock()
approximately once per thousand reboots on an i.MX8MP based system.
* Normal case
0-0022: write register AI|3a {03,02,00,00,01} Input latch P0
0-0022: write register AI|49 {fc,fd,ff,ff,fe} Interrupt mask P0
0-0022: write register AI|08 {ff,00,00,00,00} Output P3
0-0022: write register AI|12 {fc,00,00,00,00} Config P3
* Race case
0-0022: write register AI|08 {ff,00,00,00,00} Output P3
0-0022: write register AI|08 {03,02,00,00,01} *** Wrong register ***
0-0022: write register AI|12 {fc,00,00,00,00} Config P3
0-0022: write register AI|49 {fc,fd,ff,ff,fe} Interrupt mask P0
Signed-off-by: Ian Ray <ian.ray@xxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240620042915.2173-1-ian.ray@xxxxxxxxxxxxxxxx
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
Signed-off-by: Guocai He <guocai.he.cn@xxxxxxxxxxxxx>
---
This commit is to solve the CVE-2024-42253. Please merge this commit to linux-5.15.y.
drivers/gpio/gpio-pca953x.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index 4860bf3b7e00..4e97b6ae4f72 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -672,6 +672,8 @@ static void pca953x_irq_bus_sync_unlock(struct irq_data *d)
int level;
if (chip->driver_data & PCA_PCAL) {
+ guard(mutex)(&chip->i2c_lock);
This wouldn't compile on 5.15.y
We don't have scope based locking backported to 5.15.y.
drivers/gpio/gpio-pca953x.c: In function ‘pca953x_irq_bus_sync_unlock’:
drivers/gpio/gpio-pca953x.c:675:17: error: implicit declaration of
function ‘guard’ [-Werror=implicit-function-declaration]
675 | guard(mutex)(&chip->i2c_lock);
| ^~~~~
drivers/gpio/gpio-pca953x.c:675:23: error: ‘mutex’ undeclared (first use
in this function)
675 | guard(mutex)(&chip->i2c_lock);
| ^~~~~
drivers/gpio/gpio-pca953x.c:675:23: note: each undeclared identifier is
reported only once for each function it appears in
cc1: all warnings being treated as errors
Thanks,
Harshit
+
/* Enable latch on interrupt-enabled inputs */
pca953x_write_regs(chip, PCAL953X_IN_LATCH, chip->irq_mask);
