[PATCH][3/4] let's kill verify_area - convert kernel/compat.c to access_ok()

[PATCH][3/4] let's kill verify_area - convert kernel/compat.c to access_ok()

[Jesper Juhl]

Here's a patch to convert verify_area to access_ok in kernel/compat.c

diff -up linux-2.6.10-bk9-orig/kernel/compat.c linux-2.6.10-bk9/kernel/compat.c
--- linux-2.6.10-bk9-orig/kernel/compat.c	2005-01-06 22:19:13.000000000 +0100
+++ linux-2.6.10-bk9/kernel/compat.c	2005-01-07 02:06:00.000000000 +0100
@@ -26,16 +26,16 @@
 
 int get_compat_timespec(struct timespec *ts, const struct compat_timespec __user *cts)
 {
-	return (verify_area(VERIFY_READ, cts, sizeof(*cts)) ||
+	return (access_ok(VERIFY_READ, cts, sizeof(*cts)) ||
 			__get_user(ts->tv_sec, &cts->tv_sec) ||
-			__get_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
+			__get_user(ts->tv_nsec, &cts->tv_nsec)) ? 0 : -EFAULT;
 }
 
 int put_compat_timespec(const struct timespec *ts, struct compat_timespec __user *cts)
 {
-	return (verify_area(VERIFY_WRITE, cts, sizeof(*cts)) ||
+	return (access_ok(VERIFY_WRITE, cts, sizeof(*cts)) ||
 			__put_user(ts->tv_sec, &cts->tv_sec) ||
-			__put_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
+			__put_user(ts->tv_nsec, &cts->tv_nsec)) ? 0 : EFAULT;
 }
 
 static long compat_nanosleep_restart(struct restart_block *restart)
@@ -612,7 +612,7 @@ long compat_get_bitmap(unsigned long *ma
 	/* align bitmap up to nearest compat_long_t boundary */
 	bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
 
-	if (verify_area(VERIFY_READ, umask, bitmap_size / 8))
+	if (!access_ok(VERIFY_READ, umask, bitmap_size / 8) != 0)
 		return -EFAULT;
 
 	nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
@@ -653,7 +653,7 @@ long compat_put_bitmap(compat_ulong_t __
 	/* align bitmap up to nearest compat_long_t boundary */
 	bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
 
-	if (verify_area(VERIFY_WRITE, umask, bitmap_size / 8))
+	if (!access_ok(VERIFY_WRITE, umask, bitmap_size / 8) != 0)
 		return -EFAULT;
 
 	nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);

Re: [PATCH][3/4] let's kill verify_area - convert kernel/compat.c to access_ok()

[Andries Brouwer]

On Fri, Jan 07, 2005 at 02:18:44AM +0100, Jesper Juhl wrote:

> Here's a patch to convert verify_area to access_ok in kernel/compat.c
> 
> diff -up linux-2.6.10-bk9-orig/kernel/compat.c linux-2.6.10-bk9/kernel/compat.c
> --- linux-2.6.10-bk9-orig/kernel/compat.c	2005-01-06 22:19:13.000000000 +0100
> +++ linux-2.6.10-bk9/kernel/compat.c	2005-01-07 02:06:00.000000000 +0100
> @@ -26,16 +26,16 @@
>  
>  int get_compat_timespec(struct timespec *ts, const struct compat_timespec __user *cts)
>  {
> -	return (verify_area(VERIFY_READ, cts, sizeof(*cts)) ||
> +	return (access_ok(VERIFY_READ, cts, sizeof(*cts)) ||
>  			__get_user(ts->tv_sec, &cts->tv_sec) ||
> -			__get_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
> +			__get_user(ts->tv_nsec, &cts->tv_nsec)) ? 0 : -EFAULT;
>  }

This is not an equivalent transformation.

RE: [PATCH][3/4] let's kill verify_area - convert kernel/compat.c to access_ok()

[Peter Kjellerstedt]

> -----Original Message-----
> From: linux-kernel-owner@vger.kernel.org
[mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Jesper Juhl
> Sent: Friday, January 07, 2005 02:19
> To: linux-kernel
> Cc: Andrew Morton
> Subject: [PATCH][3/4] let's kill verify_area - convert kernel/compat.c
to access_ok()
> 
> Here's a patch to convert verify_area to access_ok in kernel/compat.c
> 
> diff -up linux-2.6.10-bk9-orig/kernel/compat.c 
> linux-2.6.10-bk9/kernel/compat.c
> --- linux-2.6.10-bk9-orig/kernel/compat.c	2005-01-06
22:19:13.000000000 +0100
> +++ linux-2.6.10-bk9/kernel/compat.c	2005-01-07 02:06:00.000000000
+0100

[snip]

> @@ -612,7 +612,7 @@ long compat_get_bitmap(unsigned long *ma
>  	/* align bitmap up to nearest compat_long_t boundary */
>  	bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
>  
> -	if (verify_area(VERIFY_READ, umask, bitmap_size / 8))
> +	if (!access_ok(VERIFY_READ, umask, bitmap_size / 8) != 0)

Please do not use double negations (i.e., drop the '!= 0' test 
again).

>  		return -EFAULT;
>  
>  	nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
> @@ -653,7 +653,7 @@ long compat_put_bitmap(compat_ulong_t __
>  	/* align bitmap up to nearest compat_long_t boundary */
>  	bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
>  
> -	if (verify_area(VERIFY_WRITE, umask, bitmap_size / 8))
> +	if (!access_ok(VERIFY_WRITE, umask, bitmap_size / 8) != 0)
>  		return -EFAULT;
>  
>  	nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);

//Peter