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| author | Zheyu Ma <zheyuma97@gmail.com> | 2022-08-04 15:41:24 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-08-21 16:16:13 +0300 |
| commit | 09e733d6ac948e6fda4b16252e44ea46f98fc8b4 (patch) | |
| tree | 7b1985d419b05ebd19990e3551ee3f33d7f94995 /drivers | |
| parent | bd8269e57621e5b38cc0b4bd2fa02e85c9f2a441 (diff) | |
| download | linux-09e733d6ac948e6fda4b16252e44ea46f98fc8b4.tar.xz | |
video: fbdev: arkfb: Check the size of screen before memset_io()
[ Upstream commit 96b550971c65d54d64728d8ba973487878a06454 ]
In the function arkfb_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:
[ 659.399066] BUG: unable to handle page fault for address: ffffc90003000000
[ 659.399077] #PF: supervisor write access in kernel mode
[ 659.399079] #PF: error_code(0x0002) - not-present page
[ 659.399094] RIP: 0010:memset_orig+0x33/0xb0
[ 659.399116] Call Trace:
[ 659.399122] arkfb_set_par+0x143f/0x24c0
[ 659.399130] fb_set_var+0x604/0xeb0
[ 659.399161] do_fb_ioctl+0x234/0x670
[ 659.399189] fb_ioctl+0xdd/0x130
Fix the this by checking the value of 'screen_size' before memset_io().
Fixes: 681e14730c73 ("arkfb: new framebuffer driver for ARK Logic cards")
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/video/fbdev/arkfb.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/video/fbdev/arkfb.c b/drivers/video/fbdev/arkfb.c index d94cc5ad1ef6..8d092b106470 100644 --- a/drivers/video/fbdev/arkfb.c +++ b/drivers/video/fbdev/arkfb.c @@ -794,6 +794,8 @@ static int arkfb_set_par(struct fb_info *info) value = ((value * hmul / hdiv) / 8) - 5; vga_wcrt(par->state.vgabase, 0x42, (value + 1) / 2); + if (screen_size > info->screen_size) + screen_size = info->screen_size; memset_io(info->screen_base, 0x00, screen_size); /* Device and screen back on */ svga_wcrt_mask(par->state.vgabase, 0x17, 0x80, 0x80); |