2009-11-21 18:48:09

by Roel Kluin

Subject: [PATCH] viafb: Use sizeof struct rather than pointer

The sizeof the struct should be used rather than of the pointer

Signed-off-by: Roel Kluin <[email protected]>
---
drivers/video/via/viafbdev.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

Unless I am mistaken?

diff --git a/drivers/video/via/viafbdev.c b/drivers/video/via/viafbdev.c
index 56ec696..6cf4cb8 100644
--- a/drivers/video/via/viafbdev.c
+++ b/drivers/video/via/viafbdev.c
@@ -680,7 +680,7 @@ static int viafb_ioctl(struct fb_info *info, u_int cmd, u_long arg)
if (!viafb_gamma_table)
return -ENOMEM;
if (copy_from_user(viafb_gamma_table, argp,
- sizeof(viafb_gamma_table))) {
+ sizeof(*viafb_gamma_table))) {
kfree(viafb_gamma_table);
return -EFAULT;
}

2009-11-21 18:53:19

by Thiago Farina

Subject: Re: [PATCH] viafb: Use sizeof struct rather than pointer

On Sat, Nov 21, 2009 at 5:02 PM, Roel Kluin <[email protected]> wrote:
> The returned error should be negative
>
Hum? This belong to this patch?

2009-11-21 18:49:54

by Roel Kluin

Subject: Re: [PATCH] viafb: Use sizeof struct rather than pointer

The returned error should be negative

Signed-off-by: Roel Kluin <[email protected]>
---
drivers/video/via/viafbdev.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

> Unless I am mistaken?

There was another in the same file:

diff --git a/drivers/video/via/viafbdev.c b/drivers/video/via/viafbdev.c
index 56ec696..7b181e7 100644
--- a/drivers/video/via/viafbdev.c
+++ b/drivers/video/via/viafbdev.c
@@ -680,7 +680,7 @@ static int viafb_ioctl(struct fb_info *info, u_int cmd, u_long arg)
if (!viafb_gamma_table)
return -ENOMEM;
if (copy_from_user(viafb_gamma_table, argp,
- sizeof(viafb_gamma_table))) {
+ sizeof(*viafb_gamma_table))) {
kfree(viafb_gamma_table);
return -EFAULT;
}
@@ -694,7 +694,7 @@ static int viafb_ioctl(struct fb_info *info, u_int cmd, u_long arg)
return -ENOMEM;
viafb_get_gamma_table(viafb_gamma_table);
if (copy_to_user(argp, viafb_gamma_table,
- sizeof(viafb_gamma_table))) {
+ sizeof(*viafb_gamma_table))) {
kfree(viafb_gamma_table);
return -EFAULT;
}

2009-11-21 23:59:07

by Florian Tobias Schandinat

Subject: Re: [Linux-fbdev-devel] [PATCH] viafb: Use sizeof struct rather than pointer

Hi,

Roel Kluin schrieb:
> diff --git a/drivers/video/via/viafbdev.c b/drivers/video/via/viafbdev.c
> index 56ec696..7b181e7 100644
> --- a/drivers/video/via/viafbdev.c
> +++ b/drivers/video/via/viafbdev.c
> @@ -680,7 +680,7 @@ static int viafb_ioctl(struct fb_info *info, u_int cmd, u_long arg)
> if (!viafb_gamma_table)
> return -ENOMEM;
> if (copy_from_user(viafb_gamma_table, argp,
> - sizeof(viafb_gamma_table))) {
> + sizeof(*viafb_gamma_table))) {
> kfree(viafb_gamma_table);
> return -EFAULT;
> }
> @@ -694,7 +694,7 @@ static int viafb_ioctl(struct fb_info *info, u_int cmd, u_long arg)
> return -ENOMEM;
> viafb_get_gamma_table(viafb_gamma_table);
> if (copy_to_user(argp, viafb_gamma_table,
> - sizeof(viafb_gamma_table))) {
> + sizeof(*viafb_gamma_table))) {
> kfree(viafb_gamma_table);
> return -EFAULT;
> }

I'm sorry but I fear your fix isn't correct. The reason is a few lines
above:

u32 *viafb_gamma_table;
...
viafb_gamma_table = kmalloc(256 * sizeof(u32), GFP_KERNEL);

so probably the right solution would look like this:

copy_from_user(viafb_gamma_table, argp, 256 * sizeof(u32))
copy_to_user(argp, viafb_gamma_table, 256 * sizeof(u32))

However viafb has way too many private ioctls. I would be curious
whether there exists any program that uses any of them so that they
could be tested. As this ioctl didn't work very well I vote to remove it
at least temporarily.

Thanks for highlighting this problem,


Florian Tobias Schandinat