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| author | Zheyu Ma <zheyuma97@gmail.com> | 2022-08-04 15:41:25 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-08-25 12:18:09 +0300 |
| commit | eacb50f1733660911827d7c3720f4c5425d0cdda (patch) | |
| tree | 4772578d42a12f408e504ffd1c7449215130e283 | |
| parent | 53198b81930e567ad6b879812d88052a1e8ac79e (diff) | |
| download | linux-eacb50f1733660911827d7c3720f4c5425d0cdda.tar.xz | |
video: fbdev: s3fb: Check the size of screen before memset_io()
[ Upstream commit 6ba592fa014f21f35a8ee8da4ca7b95a018f13e8 ]
In the function s3fb_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:
[ 54.083733] BUG: unable to handle page fault for address: ffffc90003000000
[ 54.083742] #PF: supervisor write access in kernel mode
[ 54.083744] #PF: error_code(0x0002) - not-present page
[ 54.083760] RIP: 0010:memset_orig+0x33/0xb0
[ 54.083782] Call Trace:
[ 54.083788] s3fb_set_par+0x1ec6/0x4040
[ 54.083806] fb_set_var+0x604/0xeb0
[ 54.083836] do_fb_ioctl+0x234/0x670
Fix the this by checking the value of 'screen_size' before memset_io().
Fixes: a268422de8bf ("fbdev driver for S3 Trio/Virge")
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/s3fb.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/video/fbdev/s3fb.c b/drivers/video/fbdev/s3fb.c index be16c349c10f..228e5ee7a547 100644 --- a/drivers/video/fbdev/s3fb.c +++ b/drivers/video/fbdev/s3fb.c @@ -902,6 +902,8 @@ static int s3fb_set_par(struct fb_info *info) value = clamp((htotal + hsstart + 1) / 2 + 2, hsstart + 4, htotal + 1); svga_wcrt_multi(par->state.vgabase, s3_dtpc_regs, value); + 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); |