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* [OE-core][master][mickledore][PATCH] grub2: fix CVE-2023-4692
@ 2023-10-20  8:09 Xiangyu Chen
  2023-10-20 22:46 ` Alexandre Belloni
  0 siblings, 1 reply; 4+ messages in thread
From: Xiangyu Chen @ 2023-10-20  8:09 UTC (permalink / raw)
  To: openembedded-core

From: Xiangyu Chen <xiangyu.chen@windriver.com>

Crafted file system images can cause heap-based buffer overflow and may
allow arbitrary code execution and secure boot bypass

Reference:
https://security-tracker.debian.org/tracker/CVE-2023-4692

Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
---
 .../grub/files/CVE-2023-4692.patch            | 98 +++++++++++++++++++
 meta/recipes-bsp/grub/grub2.inc               |  1 +
 2 files changed, 99 insertions(+)
 create mode 100644 meta/recipes-bsp/grub/files/CVE-2023-4692.patch

diff --git a/meta/recipes-bsp/grub/files/CVE-2023-4692.patch b/meta/recipes-bsp/grub/files/CVE-2023-4692.patch
new file mode 100644
index 0000000000..305fcc93d8
--- /dev/null
+++ b/meta/recipes-bsp/grub/files/CVE-2023-4692.patch
@@ -0,0 +1,98 @@
+From 43651027d24e62a7a463254165e1e46e42aecdea Mon Sep 17 00:00:00 2001
+From: Maxim Suhanov <dfirblog@gmail.com>
+Date: Mon, 28 Aug 2023 16:31:57 +0300
+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
+
+Upstream-Status: Backport from 
+[https://git.savannah.gnu.org/cgit/grub.git/commit/?id=43651027d24e62a7a463254165e1e46e42aecdea]
+CVE: 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>
+Signed-off-by: Xiangyu Chen <xiangyu.chen@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 bbdbe24..c3c4db1 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),
+-- 
+cgit v1.1
+
diff --git a/meta/recipes-bsp/grub/grub2.inc b/meta/recipes-bsp/grub/grub2.inc
index 41839698dc..5ce8699363 100644
--- a/meta/recipes-bsp/grub/grub2.inc
+++ b/meta/recipes-bsp/grub/grub2.inc
@@ -42,6 +42,7 @@ SRC_URI = "${GNU_MIRROR}/grub/grub-${PV}.tar.gz \
            file://CVE-2022-3775.patch \
            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 \
 "
 
 SRC_URI[sha256sum] = "23b64b4c741569f9426ed2e3d0e6780796fca081bee4c99f62aa3f53ae803f5f"
-- 
2.34.1



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Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-10-20  8:09 [OE-core][master][mickledore][PATCH] grub2: fix CVE-2023-4692 Xiangyu Chen
2023-10-20 22:46 ` Alexandre Belloni
2023-11-06 15:50   ` Steve Sakoman
2023-11-08  3:01     ` Xiangyu Chen

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