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staging/bcm: two information leaks in ioctl

PATCH In review Dan Carpenter 2 participants 4 messages Feb 17, 2014

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Dan Carpenter

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#0 lore raw

PATCH 1/2 staging/bcm: two information leaks in ioctl

There are a couple paths where we don't check how much data we copy back to the user.

Signed-off-by Dan Carpenter <[email protected]>
drivers/staging/bcm/Bcmchar.c +4 -0
index fdebc3bba0b5..6f1997dc44c8 100644
@@ -590,6 +590,8 @@ static int bcm_char_ioctl_gpio_multi_request(void __user *argp, struct bcm_mini_
 
 	if (IoBuffer.InputLength > sizeof(gpio_multi_info))
 		return -EINVAL;
+	if (IoBuffer.OutputLength > sizeof(gpio_multi_info))
+		IoBuffer.OutputLength = sizeof(gpio_multi_info);
 
 	if (copy_from_user(&gpio_multi_info, IoBuffer.InputBuffer, IoBuffer.InputLength))
 		return -EFAULT;

@@ -680,6 +682,8 @@ static int bcm_char_ioctl_gpio_mode_request(void __user *argp, struct bcm_mini_a
 
 	if (IoBuffer.InputLength > sizeof(gpio_multi_mode))
 		return -EINVAL;
+	if (IoBuffer.OutputLength > sizeof(gpio_multi_mode))
+		IoBuffer.OutputLength = sizeof(gpio_multi_mode);
 
 	if (copy_from_user(&gpio_multi_mode, IoBuffer.InputBuffer, IoBuffer.InputLength))
 		return -EFAULT;
#1 lore raw
Quoted 2 lines · Dan Carpenter

There are a couple paths where we don't check how much data we copy back to the user.

I'm curious, is this something smatch is only picking up now that I chopped up that mega function into lots of little functions ?

Dave

author
#2 lore raw
In reply to Dan Carpenter
Quoted 6 lines · Dave Jones
Quoted 2 lines · Dan Carpenter

There are a couple paths where we don't check how much data we copy back to the user.

I'm curious, is this something smatch is only picking up now that I chopped up that mega function into lots of little functions ?

Yes. Smatch wasn't able to parse it before the breakup. Too huge.

regards,
dan carpenter

#3 lore raw
In reply to Dan Carpenter
Quoted 9 lines · Dan Carpenter
Quoted 6 lines · Dave Jones
Quoted 2 lines · Dan Carpenter

There are a couple paths where we don't check how much data we copy back to the user.

I'm curious, is this something smatch is only picking up now that I chopped up that mega function into lots of little functions ?

Yes. Smatch wasn't able to parse it before the breakup. Too huge.

Excellent. That gives me incentive to do that sort of crap work more often.

Dave