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grub: fix CVE-2023-4692

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An out-of-bounds write flaw was found in grub2's NTFS filesystem driver.
This issue may allow an attacker to present a specially crafted NTFS
filesystem image, leading to grub's heap metadata corruption. In some
circumstances, the attack may also corrupt the UEFI firmware heap metadata.
As a result, arbitrary code execution and secure boot protection bypass
may be achieved.

References:
https://nvd.nist.gov/vuln/detail/CVE-2023-4692
https://bugzilla.redhat.com/show_bug.cgi?id=2236613

(From OE-Core rev: c89835b37366dde6c74f8221fd5a295ecabf8225)

Signed-off-by: Yogita Urade <yogita.urade@windriver.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
This commit is contained in:
Yogita Urade
2023-11-17 11:13:49 +00:00
committed by Steve Sakoman
parent e447b4139f
commit f9527fb2ac
2 changed files with 98 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
meta/recipes-bsp/grub/files/CVE-2023-4692.patch
+97
View File
@@ -0,0 +1,97 @@
From 43651027d24e62a7a463254165e1e46e42aecdea Mon Sep 17 00:00:00 2001
From: Maxim Suhanov <dfirblog@gmail.com>
Date: Thu, 16 Nov 2023 07:21:50 +0000
Subject: [PATCH] fs/ntfs: Fix an OOB write when parsing the $ATTRIBUTE_LIST
attribute for the $MFT file
When parsing an extremely fragmented $MFT file, i.e., the file described
using the $ATTRIBUTE_LIST attribute, current NTFS code will reuse a buffer
containing bytes read from the underlying drive to store sector numbers,
which are consumed later to read data from these sectors into another buffer.
These sectors numbers, two 32-bit integers, are always stored at predefined
offsets, 0x10 and 0x14, relative to first byte of the selected entry within
the $ATTRIBUTE_LIST attribute. Usually, this won't cause any problem.
However, when parsing a specially-crafted file system image, this may cause
the NTFS code to write these integers beyond the buffer boundary, likely
causing the GRUB memory allocator to misbehave or fail. These integers contain
values which are controlled by on-disk structures of the NTFS file system.
Such modification and resulting misbehavior may touch a memory range not
assigned to the GRUB and owned by firmware or another EFI application/driver.
This fix introduces checks to ensure that these sector numbers are never
written beyond the boundary.
Fixes: CVE-2023-4692
Reported-by: Maxim Suhanov <dfirblog@gmail.com>
Signed-off-by: Maxim Suhanov <dfirblog@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
CVE: CVE-2023-4692
Upstream-Status: Backport [https://git.savannah.gnu.org/cgit/grub.git/commit/?id=43651027d24e62a7a463254165e1e46e42aecdea]
Signed-off-by: Yogita Urade <yogita.urade@windriver.com>
---
grub-core/fs/ntfs.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
diff --git a/grub-core/fs/ntfs.c b/grub-core/fs/ntfs.c
index 2f34f76..6009e49 100644
--- a/grub-core/fs/ntfs.c
+++ b/grub-core/fs/ntfs.c
@@ -184,7 +184,7 @@ find_attr (struct grub_ntfs_attr *at, grub_uint8_t attr)
}
if (at->attr_end)
{
- grub_uint8_t *pa;
+ grub_uint8_t *pa, *pa_end;
at->emft_buf = grub_malloc (at->mft->data->mft_size << GRUB_NTFS_BLK_SHR);
if (at->emft_buf == NULL)
@@ -209,11 +209,13 @@ find_attr (struct grub_ntfs_attr *at, grub_uint8_t attr)
}
at->attr_nxt = at->edat_buf;
at->attr_end = at->edat_buf + u32at (pa, 0x30);
+ pa_end = at->edat_buf + n;
}
else
{
at->attr_nxt = at->attr_end + u16at (pa, 0x14);
at->attr_end = at->attr_end + u32at (pa, 4);
+ pa_end = at->mft->buf + (at->mft->data->mft_size << GRUB_NTFS_BLK_SHR);
}
at->flags |= GRUB_NTFS_AF_ALST;
while (at->attr_nxt < at->attr_end)
@@ -230,6 +232,13 @@ find_attr (struct grub_ntfs_attr *at, grub_uint8_t attr)
at->flags |= GRUB_NTFS_AF_GPOS;
at->attr_cur = at->attr_nxt;
pa = at->attr_cur;
+
+ if ((pa >= pa_end) || (pa_end - pa < 0x18))
+ {
+ grub_error (GRUB_ERR_BAD_FS, "can\'t parse attribute list");
+ return NULL;
+ }
+
grub_set_unaligned32 ((char *) pa + 0x10,
grub_cpu_to_le32 (at->mft->data->mft_start));
grub_set_unaligned32 ((char *) pa + 0x14,
@@ -240,6 +249,13 @@ find_attr (struct grub_ntfs_attr *at, grub_uint8_t attr)
{
if (*pa != attr)
break;
+
+ if ((pa >= pa_end) || (pa_end - pa < 0x18))
+ {
+ grub_error (GRUB_ERR_BAD_FS, "can\'t parse attribute list");
+ return NULL;
+ }
+
if (read_attr
(at, pa + 0x10,
u32at (pa, 0x10) * (at->mft->data->mft_size << GRUB_NTFS_BLK_SHR),
--
2.40.0
meta/recipes-bsp/grub/grub2.inc
+1
View File
@@ -38,6 +38,7 @@ SRC_URI = "${GNU_MIRROR}/grub/grub-${PV}.tar.gz \
file://loader-efi-chainloader-Simplify-the-loader-state.patch \
file://commands-boot-Add-API-to-pass-context-to-loader.patch \
file://CVE-2022-28736-loader-efi-chainloader-Use-grub_loader_set_ex.patch \
file://CVE-2023-4692.patch \
"
SRC_URI[sha256sum] = "23b64b4c741569f9426ed2e3d0e6780796fca081bee4c99f62aa3f53ae803f5f"