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authorZheyu Ma <zheyuma97@gmail.com>2021-07-26 10:03:55 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-09-18 13:40:22 +0200
commitbcc61adefd7845fa89d6dd0514a0ee8b545f85ef (patch)
tree7692c599520881ec7b75c9e490b19173d130bdc3
parent63abc0eb8af54cf24df2bad768bab4dd561c2999 (diff)
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video: fbdev: riva: Error out if 'pixclock' equals zero
[ Upstream commit f92763cb0feba247e0939ed137b495601fd072a5 ] The userspace program could pass any values to the driver through ioctl() interface. If the driver doesn't check the value of 'pixclock', it may cause divide error. Fix this by checking whether 'pixclock' is zero first. The following log reveals it: [ 33.396850] divide error: 0000 [#1] PREEMPT SMP KASAN PTI [ 33.396864] CPU: 5 PID: 11754 Comm: i740 Not tainted 5.14.0-rc2-00513-gac532c9bbcfb-dirty #222 [ 33.396883] RIP: 0010:riva_load_video_mode+0x417/0xf70 [ 33.396969] Call Trace: [ 33.396973] ? debug_smp_processor_id+0x1c/0x20 [ 33.396984] ? tick_nohz_tick_stopped+0x1a/0x90 [ 33.396996] ? rivafb_copyarea+0x3c0/0x3c0 [ 33.397003] ? wake_up_klogd.part.0+0x99/0xd0 [ 33.397014] ? vprintk_emit+0x110/0x4b0 [ 33.397024] ? vprintk_default+0x26/0x30 [ 33.397033] ? vprintk+0x9c/0x1f0 [ 33.397041] ? printk+0xba/0xed [ 33.397054] ? record_print_text.cold+0x16/0x16 [ 33.397063] ? __kasan_check_read+0x11/0x20 [ 33.397074] ? profile_tick+0xc0/0x100 [ 33.397084] ? __sanitizer_cov_trace_const_cmp4+0x24/0x80 [ 33.397094] ? riva_set_rop_solid+0x2a0/0x2a0 [ 33.397102] rivafb_set_par+0xbe/0x610 [ 33.397111] ? riva_set_rop_solid+0x2a0/0x2a0 [ 33.397119] fb_set_var+0x5bf/0xeb0 [ 33.397127] ? fb_blank+0x1a0/0x1a0 [ 33.397134] ? lock_acquire+0x1ef/0x530 [ 33.397143] ? lock_release+0x810/0x810 [ 33.397151] ? lock_is_held_type+0x100/0x140 [ 33.397159] ? ___might_sleep+0x1ee/0x2d0 [ 33.397170] ? __mutex_lock+0x620/0x1190 [ 33.397180] ? trace_hardirqs_on+0x6a/0x1c0 [ 33.397190] do_fb_ioctl+0x31e/0x700 Signed-off-by: Zheyu Ma <zheyuma97@gmail.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/1627293835-17441-4-git-send-email-zheyuma97@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--drivers/video/fbdev/riva/fbdev.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/video/fbdev/riva/fbdev.c b/drivers/video/fbdev/riva/fbdev.c
index ce55b9d2e862..7dd621c7afe4 100644
--- a/drivers/video/fbdev/riva/fbdev.c
+++ b/drivers/video/fbdev/riva/fbdev.c
@@ -1084,6 +1084,9 @@ static int rivafb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
int mode_valid = 0;
NVTRACE_ENTER();
+ if (!var->pixclock)
+ return -EINVAL;
+
switch (var->bits_per_pixel) {
case 1 ... 8:
var->red.offset = var->green.offset = var->blue.offset = 0;