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authorGeorge Kennedy <george.kennedy@oracle.com>2020-07-07 15:26:03 -0400
committerBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>2020-09-08 13:33:01 +0200
commita49145acfb975d921464b84fe00279f99827d816 (patch)
treefc4f2b412cc723119d7b77c0dc0fcbed1701b68f /drivers
parent54d04ea8cdbd143496e4f5cc9c0a9f86c0e55a2e (diff)
fbmem: add margin check to fb_check_caps()
A fb_ioctl() FBIOPUT_VSCREENINFO call with invalid xres setting or yres setting in struct fb_var_screeninfo will result in a KASAN: vmalloc-out-of-bounds failure in bitfill_aligned() as the margins are being cleared. The margins are cleared in chunks and if the xres setting or yres setting is a value of zero upto the chunk size, the failure will occur. Add a margin check to validate xres and yres settings. Signed-off-by: George Kennedy <george.kennedy@oracle.com> Reported-by: syzbot+e5fd3e65515b48c02a30@syzkaller.appspotmail.com Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Dhaval Giani <dhaval.giani@oracle.com> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Link: https://patchwork.freedesktop.org/patch/msgid/1594149963-13801-1-git-send-email-george.kennedy@oracle.com
Diffstat (limited to 'drivers')
-rw-r--r--drivers/video/fbdev/core/fbmem.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index cc69649dce95..8268bbee8cae 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1006,6 +1006,10 @@ fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var)
return 0;
}
+ /* bitfill_aligned() assumes that it's at least 8x8 */
+ if (var->xres < 8 || var->yres < 8)
+ return -EINVAL;
+
ret = info->fbops->fb_check_var(var, info);
if (ret)