grub2/0249-Fix-a-regression-caused-by-efi-fix-some-malformed-de.patch
Peter Jones 47cf63735c "Minor" bug fixes
Resolves: CVE-2020-10713
Resolves: CVE-2020-14308
Resolves: CVE-2020-14309
Resolves: CVE-2020-14310
Resolves: CVE-2020-14311
Resolves: CVE-2020-15705
Resolves: CVE-2020-15706
Resolves: CVE-2020-15707

Signed-off-by: Peter Jones <pjones@redhat.com>
2020-08-10 22:02:39 -04:00

84 lines
3.2 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Chris Coulson <chris.coulson@canonical.com>
Date: Wed, 22 Jul 2020 17:06:04 +0100
Subject: [PATCH] Fix a regression caused by "efi: fix some malformed device
path arithmetic errors"
This commit introduced a bogus check inside copy_file_path to
determine whether the destination grub_efi_file_path_device_path_t
was valid before anything was copied to it. Depending on the
contents of the heap buffer, this check could fail which would
result in copy_file_path returning early.
Without any error propagated to the caller, make_file_path would
then try to advance the invalid device path node with
GRUB_EFI_NEXT_DEVICE_PATH, which would also fail, returning a NULL
pointer that would subsequently be dereferenced.
Remove the bogus check, and also propagate errors from copy_file_path.
---
grub-core/loader/efi/chainloader.c | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)
diff --git a/grub-core/loader/efi/chainloader.c b/grub-core/loader/efi/chainloader.c
index 5f7c6cfe105..3dfa41bb49d 100644
--- a/grub-core/loader/efi/chainloader.c
+++ b/grub-core/loader/efi/chainloader.c
@@ -115,7 +115,7 @@ grub_chainloader_boot (void)
return grub_errno;
}
-static void
+static grub_err_t
copy_file_path (grub_efi_file_path_device_path_t *fp,
const char *str, grub_efi_uint16_t len)
{
@@ -125,15 +125,9 @@ copy_file_path (grub_efi_file_path_device_path_t *fp,
fp->header.type = GRUB_EFI_MEDIA_DEVICE_PATH_TYPE;
fp->header.subtype = GRUB_EFI_FILE_PATH_DEVICE_PATH_SUBTYPE;
- if (!GRUB_EFI_DEVICE_PATH_VALID ((grub_efi_device_path_t *)fp))
- {
- grub_error (GRUB_ERR_BAD_ARGUMENT, "EFI Device Path is invalid");
- return;
- }
-
path_name = grub_calloc (len, GRUB_MAX_UTF16_PER_UTF8 * sizeof (*path_name));
if (!path_name)
- return;
+ return grub_error (GRUB_ERR_OUT_OF_MEMORY, "failed to allocate path buffer");
size = grub_utf8_to_utf16 (path_name, len * GRUB_MAX_UTF16_PER_UTF8,
(const grub_uint8_t *) str, len, 0);
@@ -146,6 +140,7 @@ copy_file_path (grub_efi_file_path_device_path_t *fp,
fp->path_name[size++] = '\0';
fp->header.length = size * sizeof (grub_efi_char16_t) + sizeof (*fp);
grub_free (path_name);
+ return GRUB_ERR_NONE;
}
static grub_efi_device_path_t *
@@ -203,13 +198,19 @@ make_file_path (grub_efi_device_path_t *dp, const char *filename)
/* Fill the file path for the directory. */
d = (grub_efi_device_path_t *) ((char *) file_path
+ ((char *) d - (char *) dp));
- copy_file_path ((grub_efi_file_path_device_path_t *) d,
- dir_start, dir_end - dir_start);
+ if (copy_file_path ((grub_efi_file_path_device_path_t *) d,
+ dir_start, dir_end - dir_start) != GRUB_ERR_NONE)
+ {
+ fail:
+ grub_free (file_path);
+ return 0;
+ }
/* Fill the file path for the file. */
d = GRUB_EFI_NEXT_DEVICE_PATH (d);
- copy_file_path ((grub_efi_file_path_device_path_t *) d,
- dir_end + 1, grub_strlen (dir_end + 1));
+ if (copy_file_path ((grub_efi_file_path_device_path_t *) d,
+ dir_end + 1, grub_strlen (dir_end + 1)) != GRUB_ERR_NONE)
+ goto fail;
/* Fill the end of device path nodes. */
d = GRUB_EFI_NEXT_DEVICE_PATH (d);