grub: fix a possible integer overflow

This patch adds a fix for a possible integer overflow in grub's
video/fb/video_fb. It is a part of a security series [1].

[1] https://lists.gnu.org/archive/html/grub-devel/2021-03/msg00007.html

(From OE-Core rev: d15e7cc6fc7de358da2fd1faa8a8ea5bc2fabe98)

Signed-off-by: Marta Rybczynska <marta.rybczynska@huawei.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Marta Rybczynska
2022-02-18 11:05:42 +01:00
committed by Richard Purdie
parent 628257a582
commit eca24c02ea
2 changed files with 40 additions and 0 deletions

View File

@@ -0,0 +1,39 @@
From aac5574ff340a665ccc78d4c3d61596ac67acbbe Mon Sep 17 00:00:00 2001
From: Darren Kenny <darren.kenny@oracle.com>
Date: Fri, 4 Dec 2020 14:51:30 +0000
Subject: [PATCH] video/fb/video_fb: Fix possible integer overflow
It is minimal possibility that the values being used here will overflow.
So, change the code to use the safemath function grub_mul() to ensure
that doesn't happen.
Fixes: CID 73761
Signed-off-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Upstream-Status: Backport [https://git.savannah.gnu.org/cgit/grub.git/commit/?id=08413f2f4edec0e2d9bf15f836f6ee5ca2e379cb]
Signed-off-by: Marta Rybczynska <marta.rybczynska@huawei.com>
---
grub-core/video/fb/video_fb.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/grub-core/video/fb/video_fb.c b/grub-core/video/fb/video_fb.c
index 1c9a138..ae6b89f 100644
--- a/grub-core/video/fb/video_fb.c
+++ b/grub-core/video/fb/video_fb.c
@@ -1537,7 +1537,13 @@ doublebuf_pageflipping_init (struct grub_video_mode_info *mode_info,
volatile void *page1_ptr)
{
grub_err_t err;
- grub_size_t page_size = mode_info->pitch * mode_info->height;
+ grub_size_t page_size = 0;
+
+ if (grub_mul (mode_info->pitch, mode_info->height, &page_size))
+ {
+ /* Shouldn't happen, but if it does we've a bug. */
+ return GRUB_ERR_BUG;
+ }
framebuffer.offscreen_buffer = grub_malloc (page_size);
if (! framebuffer.offscreen_buffer)

View File

@@ -80,6 +80,7 @@ SRC_URI = "${GNU_MIRROR}/grub/grub-${PV}.tar.gz \
file://0031-video-efi_gop-Remove-unnecessary-return-value-of-gru.patch \
file://0032-video-fb-fbfill-Fix-potential-integer-overflow.patch \
file://0033-video-fb-video_fb-Fix-multiple-integer-overflows.patch \
file://0034-video-fb-video_fb-Fix-possible-integer-overflow.patch \
"
SRC_URI[md5sum] = "5ce674ca6b2612d8939b9e6abed32934"
SRC_URI[sha256sum] = "f10c85ae3e204dbaec39ae22fa3c5e99f0665417e91c2cb49b7e5031658ba6ea"