diff mbox series

[mickledore,2/5] grub2: fix CVE-2023-4693

Message ID afcb86b8b7936056549600c71a171f9c17ca6980.1698766338.git.steve@sakoman.com
State New
Headers show
Series [mickledore,1/5] grub2: fix CVE-2023-4692 | expand

Commit Message

Steve Sakoman Oct. 31, 2023, 3:35 p.m. UTC 
From: Xiangyu Chen <xiangyu.chen@windriver.com>

There an out-of-bounds read at fs/ntfs.c, a physically present attacker
may leverage that by presenting a specially crafted NTFS file system
image to read arbitrary memory locations. A successful attack may allow
sensitive data cached in memory or EFI variables values to be leaked
presenting a high Confidentiality risk.

Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
---
 .../grub/files/CVE-2023-4693.patch            | 63 +++++++++++++++++++
 meta/recipes-bsp/grub/grub2.inc               |  1 +
 2 files changed, 64 insertions(+)
 create mode 100644 meta/recipes-bsp/grub/files/CVE-2023-4693.patch
diff mbox series

Patch

diff --git a/meta/recipes-bsp/grub/files/CVE-2023-4693.patch b/meta/recipes-bsp/grub/files/CVE-2023-4693.patch
new file mode 100644
index 0000000000..544226a9aa
--- /dev/null
+++ b/meta/recipes-bsp/grub/files/CVE-2023-4693.patch
@@ -0,0 +1,63 @@ 
+From 0ed2458cc4eff6d9a9199527e2a0b6d445802f94 Mon Sep 17 00:00:00 2001
+From: Maxim Suhanov <dfirblog@gmail.com>
+Date: Mon, 28 Aug 2023 16:32:33 +0300
+Subject: fs/ntfs: Fix an OOB read when reading data from the resident $DATA
+ attribute
+
+When reading a file containing resident data, i.e., the file data is stored in
+the $DATA attribute within the NTFS file record, not in external clusters,
+there are no checks that this resident data actually fits the corresponding
+file record segment.
+
+When parsing a specially-crafted file system image, the current NTFS code will
+read the file data from an arbitrary, attacker-chosen memory offset and of
+arbitrary, attacker-chosen length.
+
+This allows an attacker to display arbitrary chunks of memory, which could
+contain sensitive information like password hashes or even plain-text,
+obfuscated passwords from BS EFI variables.
+
+This fix implements a check to ensure that resident data is read from the
+corresponding file record segment only.
+
+Fixes: CVE-2023-4693
+
+Upstream-Status: Backport from 
+[https://git.savannah.gnu.org/cgit/grub.git/commit/?id=0ed2458cc4eff6d9a9199527e2a0b6d445802f94]
+CVE: CVE-2023-4693
+
+Reported-by: Maxim Suhanov <dfirblog@gmail.com>
+Signed-off-by: Maxim Suhanov <dfirblog@gmail.com>
+Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
+Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
+---
+ grub-core/fs/ntfs.c | 13 ++++++++++++-
+ 1 file changed, 12 insertions(+), 1 deletion(-)
+
+diff --git a/grub-core/fs/ntfs.c b/grub-core/fs/ntfs.c
+index c3c4db1..a68e173 100644
+--- a/grub-core/fs/ntfs.c
++++ b/grub-core/fs/ntfs.c
+@@ -401,7 +401,18 @@ read_data (struct grub_ntfs_attr *at, grub_uint8_t *pa, grub_uint8_t *dest,
+     {
+       if (ofs + len > u32at (pa, 0x10))
+ 	return grub_error (GRUB_ERR_BAD_FS, "read out of range");
+-      grub_memcpy (dest, pa + u32at (pa, 0x14) + ofs, len);
++
++      if (u32at (pa, 0x10) > (at->mft->data->mft_size << GRUB_NTFS_BLK_SHR))
++	return grub_error (GRUB_ERR_BAD_FS, "resident attribute too large");
++
++      if (pa >= at->mft->buf + (at->mft->data->mft_size << GRUB_NTFS_BLK_SHR))
++	return grub_error (GRUB_ERR_BAD_FS, "resident attribute out of range");
++
++      if (u16at (pa, 0x14) + u32at (pa, 0x10) >
++	  (grub_addr_t) at->mft->buf + (at->mft->data->mft_size << GRUB_NTFS_BLK_SHR) - (grub_addr_t) pa)
++	return grub_error (GRUB_ERR_BAD_FS, "resident attribute out of range");
++
++      grub_memcpy (dest, pa + u16at (pa, 0x14) + ofs, len);
+       return 0;
+     }
+ 
+-- 
+cgit v1.1
+
diff --git a/meta/recipes-bsp/grub/grub2.inc b/meta/recipes-bsp/grub/grub2.inc
index ac73a0b940..fa949fc081 100644
--- a/meta/recipes-bsp/grub/grub2.inc
+++ b/meta/recipes-bsp/grub/grub2.inc
@@ -43,6 +43,7 @@  SRC_URI = "${GNU_MIRROR}/grub/grub-${PV}.tar.gz \
            file://0001-risc-v-Handle-R_RISCV_CALL_PLT-reloc.patch \
            file://0001-fs-ext2-Ignore-checksum-seed-incompat-feature.patch \
            file://CVE-2023-4692.patch \
+           file://CVE-2023-4693.patch \
 "
 
 SRC_URI[sha256sum] = "23b64b4c741569f9426ed2e3d0e6780796fca081bee4c99f62aa3f53ae803f5f"