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| author | Zheyu Ma <zheyuma97@gmail.com> | 2022-08-03 12:24:19 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-08-25 12:18:38 +0300 |
| commit | 2b7f559152a33c55f51b569b22efbe5e24886798 (patch) | |
| tree | 91c2bf8f90a9b85afd123d60652e035cdd9334e5 /README | |
| parent | 5e14b04c8459afbeea1eeb74e81af86d7b196a4d (diff) | |
| download | linux-2b7f559152a33c55f51b569b22efbe5e24886798.tar.xz | |
video: fbdev: i740fb: Check the argument of i740_calc_vclk()
[ Upstream commit 40bf722f8064f50200b8c4f8946cd625b441dda9 ]
Since the user can control the arguments of the ioctl() from the user
space, under special arguments that may result in a divide-by-zero bug.
If the user provides an improper 'pixclock' value that makes the argumet
of i740_calc_vclk() less than 'I740_RFREQ_FIX', it will cause a
divide-by-zero bug in:
drivers/video/fbdev/i740fb.c:353 p_best = min(15, ilog2(I740_MAX_VCO_FREQ / (freq / I740_RFREQ_FIX)));
The following log can reveal it:
divide error: 0000 [#1] PREEMPT SMP KASAN PTI
RIP: 0010:i740_calc_vclk drivers/video/fbdev/i740fb.c:353 [inline]
RIP: 0010:i740fb_decode_var drivers/video/fbdev/i740fb.c:646 [inline]
RIP: 0010:i740fb_set_par+0x163f/0x3b70 drivers/video/fbdev/i740fb.c:742
Call Trace:
fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1034
do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1110
fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1189
Fix this by checking the argument of i740_calc_vclk() first.
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 'README')
0 files changed, 0 insertions, 0 deletions