diff options
Diffstat (limited to 'meta/recipes-bsp/grub/files/CVE-2022-28735-kern-efi-sb-Reject-non-kernel-files-in-the-shim_lock.patch')
| -rw-r--r-- | meta/recipes-bsp/grub/files/CVE-2022-28735-kern-efi-sb-Reject-non-kernel-files-in-the-shim_lock.patch | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/meta/recipes-bsp/grub/files/CVE-2022-28735-kern-efi-sb-Reject-non-kernel-files-in-the-shim_lock.patch b/meta/recipes-bsp/grub/files/CVE-2022-28735-kern-efi-sb-Reject-non-kernel-files-in-the-shim_lock.patch new file mode 100644 index 0000000000..7a59f10bfb --- /dev/null +++ b/meta/recipes-bsp/grub/files/CVE-2022-28735-kern-efi-sb-Reject-non-kernel-files-in-the-shim_lock.patch @@ -0,0 +1,111 @@ +From 6fe755c5c07bb386fda58306bfd19e4a1c974c53 Mon Sep 17 00:00:00 2001 +From: Julian Andres Klode <julian.klode@canonical.com> +Date: Thu, 2 Dec 2021 15:03:53 +0100 +Subject: [PATCH] kern/efi/sb: Reject non-kernel files in the shim_lock + verifier + +We must not allow other verifiers to pass things like the GRUB modules. +Instead of maintaining a blocklist, maintain an allowlist of things +that we do not care about. + +This allowlist really should be made reusable, and shared by the +lockdown verifier, but this is the minimal patch addressing +security concerns where the TPM verifier was able to mark modules +as verified (or the OpenPGP verifier for that matter), when it +should not do so on shim-powered secure boot systems. + +Fixes: CVE-2022-28735 + +Signed-off-by: Julian Andres Klode <julian.klode@canonical.com> +Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> + +Upstream-Status: Backport +CVE:CVE-2022-28735 + +Reference to upstream patch: +https://git.savannah.gnu.org/cgit/grub.git/commit/?id=6fe755c5c07bb386fda58306bfd19e4a1c974c53 + +Signed-off-by: Yongxin Liu <yongxin.liu@windriver.com> +--- + grub-core/kern/efi/sb.c | 39 ++++++++++++++++++++++++++++++++++++--- + include/grub/verify.h | 1 + + 2 files changed, 37 insertions(+), 3 deletions(-) + +diff --git a/grub-core/kern/efi/sb.c b/grub-core/kern/efi/sb.c +index c52ec6226..89c4bb3fd 100644 +--- a/grub-core/kern/efi/sb.c ++++ b/grub-core/kern/efi/sb.c +@@ -119,10 +119,11 @@ shim_lock_verifier_init (grub_file_t io __attribute__ ((unused)), + void **context __attribute__ ((unused)), + enum grub_verify_flags *flags) + { +- *flags = GRUB_VERIFY_FLAGS_SKIP_VERIFICATION; ++ *flags = GRUB_VERIFY_FLAGS_NONE; + + switch (type & GRUB_FILE_TYPE_MASK) + { ++ /* Files we check. */ + case GRUB_FILE_TYPE_LINUX_KERNEL: + case GRUB_FILE_TYPE_MULTIBOOT_KERNEL: + case GRUB_FILE_TYPE_BSD_KERNEL: +@@ -130,11 +131,43 @@ shim_lock_verifier_init (grub_file_t io __attribute__ ((unused)), + case GRUB_FILE_TYPE_PLAN9_KERNEL: + case GRUB_FILE_TYPE_EFI_CHAINLOADED_IMAGE: + *flags = GRUB_VERIFY_FLAGS_SINGLE_CHUNK; ++ return GRUB_ERR_NONE; + +- /* Fall through. */ ++ /* Files that do not affect secureboot state. */ ++ case GRUB_FILE_TYPE_NONE: ++ case GRUB_FILE_TYPE_LOOPBACK: ++ case GRUB_FILE_TYPE_LINUX_INITRD: ++ case GRUB_FILE_TYPE_OPENBSD_RAMDISK: ++ case GRUB_FILE_TYPE_XNU_RAMDISK: ++ case GRUB_FILE_TYPE_SIGNATURE: ++ case GRUB_FILE_TYPE_PUBLIC_KEY: ++ case GRUB_FILE_TYPE_PUBLIC_KEY_TRUST: ++ case GRUB_FILE_TYPE_PRINT_BLOCKLIST: ++ case GRUB_FILE_TYPE_TESTLOAD: ++ case GRUB_FILE_TYPE_GET_SIZE: ++ case GRUB_FILE_TYPE_FONT: ++ case GRUB_FILE_TYPE_ZFS_ENCRYPTION_KEY: ++ case GRUB_FILE_TYPE_CAT: ++ case GRUB_FILE_TYPE_HEXCAT: ++ case GRUB_FILE_TYPE_CMP: ++ case GRUB_FILE_TYPE_HASHLIST: ++ case GRUB_FILE_TYPE_TO_HASH: ++ case GRUB_FILE_TYPE_KEYBOARD_LAYOUT: ++ case GRUB_FILE_TYPE_PIXMAP: ++ case GRUB_FILE_TYPE_GRUB_MODULE_LIST: ++ case GRUB_FILE_TYPE_CONFIG: ++ case GRUB_FILE_TYPE_THEME: ++ case GRUB_FILE_TYPE_GETTEXT_CATALOG: ++ case GRUB_FILE_TYPE_FS_SEARCH: ++ case GRUB_FILE_TYPE_LOADENV: ++ case GRUB_FILE_TYPE_SAVEENV: ++ case GRUB_FILE_TYPE_VERIFY_SIGNATURE: ++ *flags = GRUB_VERIFY_FLAGS_SKIP_VERIFICATION; ++ return GRUB_ERR_NONE; + ++ /* Other files. */ + default: +- return GRUB_ERR_NONE; ++ return grub_error (GRUB_ERR_ACCESS_DENIED, N_("prohibited by secure boot policy")); + } + } + +diff --git a/include/grub/verify.h b/include/grub/verify.h +index cd129c398..672ae1692 100644 +--- a/include/grub/verify.h ++++ b/include/grub/verify.h +@@ -24,6 +24,7 @@ + + enum grub_verify_flags + { ++ GRUB_VERIFY_FLAGS_NONE = 0, + GRUB_VERIFY_FLAGS_SKIP_VERIFICATION = 1, + GRUB_VERIFY_FLAGS_SINGLE_CHUNK = 2, + /* Defer verification to another authority. */ +-- +2.34.1 + |