diff options
| author | Zheyu Ma <zheyuma97@gmail.com> | 2022-08-04 20:41:23 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-08-25 11:11:27 +0200 |
| commit | 73280a184aa2e1a625ce54ce761042955cc79cd0 (patch) | |
| tree | 61dbe62a09e04457cc76842f028aa7c05e46b768 | |
| parent | 65dad30796ee1bed0c349efb790403cf870a5e41 (diff) | |
| download | linux-rt-73280a184aa2e1a625ce54ce761042955cc79cd0.tar.gz | |
video: fbdev: vt8623fb: Check the size of screen before memset_io()
[ Upstream commit ec0754c60217248fa77cc9005d66b2b55200ac06 ]
In the function vt8623fb_set_par(), the value of 'screen_size' is
calculated by the user input. If the user provides the improper value,
the value of 'screen_size' may larger than 'info->screen_size', which
may cause the following bug:
[ 583.339036] BUG: unable to handle page fault for address: ffffc90005000000
[ 583.339049] #PF: supervisor write access in kernel mode
[ 583.339052] #PF: error_code(0x0002) - not-present page
[ 583.339074] RIP: 0010:memset_orig+0x33/0xb0
[ 583.339110] Call Trace:
[ 583.339118] vt8623fb_set_par+0x11cd/0x21e0
[ 583.339146] fb_set_var+0x604/0xeb0
[ 583.339181] do_fb_ioctl+0x234/0x670
[ 583.339209] fb_ioctl+0xdd/0x130
Fix the this by checking the value of 'screen_size' before memset_io().
Fixes: 558b7bd86c32 ("vt8623fb: new framebuffer driver for VIA VT8623")
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/video/fbdev/vt8623fb.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/video/fbdev/vt8623fb.c b/drivers/video/fbdev/vt8623fb.c index 5cac871db3ee..cbae9c510092 100644 --- a/drivers/video/fbdev/vt8623fb.c +++ b/drivers/video/fbdev/vt8623fb.c @@ -504,6 +504,8 @@ static int vt8623fb_set_par(struct fb_info *info) (info->var.vmode & FB_VMODE_DOUBLE) ? 2 : 1, 1, 1, info->node); + if (screen_size > info->screen_size) + screen_size = info->screen_size; memset_io(info->screen_base, 0x00, screen_size); /* Device and screen back on */ |