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authorTomi Valkeinen <tomi.valkeinen@ti.com>2018-09-26 18:11:22 +0200
committerBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>2018-09-26 18:11:22 +0200
commit1bafcbf59fed92af58955024452f45430d3898c5 (patch)
treeee45bb8b910f281248c4528ddc290e75e4253241
parentpxa168fb: prepare the clock (diff)
downloadlinux-1bafcbf59fed92af58955024452f45430d3898c5.tar.xz
linux-1bafcbf59fed92af58955024452f45430d3898c5.zip
fbdev/omapfb: fix omapfb_memory_read infoleak
OMAPFB_MEMORY_READ ioctl reads pixels from the LCD's memory and copies them to a userspace buffer. The code has two issues: - The user provided width and height could be large enough to overflow the calculations - The copy_to_user() can copy uninitialized memory to the userspace, which might contain sensitive kernel information. Fix these by limiting the width & height parameters, and only copying the amount of data that we actually received from the LCD. Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com> Reported-by: Jann Horn <jannh@google.com> Cc: stable@vger.kernel.org Cc: security@kernel.org Cc: Will Deacon <will.deacon@arm.com> Cc: Jann Horn <jannh@google.com> Cc: Tony Lindgren <tony@atomide.com> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
-rw-r--r--drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c b/drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c
index ef69273074ba..a3edb20ea4c3 100644
--- a/drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c
+++ b/drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c
@@ -496,6 +496,9 @@ static int omapfb_memory_read(struct fb_info *fbi,
if (!access_ok(VERIFY_WRITE, mr->buffer, mr->buffer_size))
return -EFAULT;
+ if (mr->w > 4096 || mr->h > 4096)
+ return -EINVAL;
+
if (mr->w * mr->h * 3 > mr->buffer_size)
return -EINVAL;
@@ -509,7 +512,7 @@ static int omapfb_memory_read(struct fb_info *fbi,
mr->x, mr->y, mr->w, mr->h);
if (r > 0) {
- if (copy_to_user(mr->buffer, buf, mr->buffer_size))
+ if (copy_to_user(mr->buffer, buf, r))
r = -EFAULT;
}