[PATCH] neofb: Fix pseudo_palette array overrun in neofb_setcolreg

From: Antonino A. Daplas
Date: Thu May 31 2007 - 02:05:20 EST


The pseudo_palette has room for 16 entries only, but in truecolor mode, it
attempts to write 256.

Signed-off-by: Antonino Daplas <adaplas@xxxxxxxxx>
Acked-by: Tero Roponen <teanropo@xxxxxx>
---

Tero Roponen wrote:
> On Thu, 31 May 2007, Antonino A. Daplas wrote:
>
>> On Wed, 2007-05-30 at 19:33 -0700, Linus Torvalds wrote:
>>> On Tue, 29 May 2007, Michal Piotrowski wrote:
>>>> TTY
>>>>
>>>> Subject : tty-related oops in latest kernel(s)
>>>> References : http://lkml.org/lkml/2007/5/27/104
>>>> Submitter : Tero Roponen <teanropo@xxxxxx>
>>>> Status : problem is being debugged
>>> People seem to have debugged this to neofb palette handling, but I haven't
>>> seen a patch. Antonino?
>>>
>> Already posted one for testing. I'm waiting for Tero to confirm.
>>
>> Tony
>>
>
> Ok, I tested all the cases I have reported: no corruption
> and nothing in slabinfo -v. This seems to be the right fix.
>

Okay, thanks for testing.

Tony

drivers/video/neofb.c | 30 ++++++++++++++++--------------
1 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/drivers/video/neofb.c b/drivers/video/neofb.c
index bd30aba..731d7a5 100644
--- a/drivers/video/neofb.c
+++ b/drivers/video/neofb.c
@@ -1286,34 +1286,36 @@ static int neofb_setcolreg(u_int regno,
if (regno >= fb->cmap.len || regno > 255)
return -EINVAL;

- switch (fb->var.bits_per_pixel) {
- case 8:
+ if (fb->var.bits_per_pixel <= 8) {
outb(regno, 0x3c8);

outb(red >> 10, 0x3c9);
outb(green >> 10, 0x3c9);
outb(blue >> 10, 0x3c9);
- break;
- case 16:
- ((u32 *) fb->pseudo_palette)[regno] =
+ } else if (regno < 16) {
+ switch (fb->var.bits_per_pixel) {
+ case 16:
+ ((u32 *) fb->pseudo_palette)[regno] =
((red & 0xf800)) | ((green & 0xfc00) >> 5) |
((blue & 0xf800) >> 11);
- break;
- case 24:
- ((u32 *) fb->pseudo_palette)[regno] =
+ break;
+ case 24:
+ ((u32 *) fb->pseudo_palette)[regno] =
((red & 0xff00) << 8) | ((green & 0xff00)) |
((blue & 0xff00) >> 8);
- break;
+ break;
#ifdef NO_32BIT_SUPPORT_YET
- case 32:
- ((u32 *) fb->pseudo_palette)[regno] =
+ case 32:
+ ((u32 *) fb->pseudo_palette)[regno] =
((transp & 0xff00) << 16) | ((red & 0xff00) << 8) |
((green & 0xff00)) | ((blue & 0xff00) >> 8);
- break;
+ break;
#endif
- default:
- return 1;
+ default:
+ return 1;
+ }
}
+
return 0;
}


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