mirror of
https://src.fedoraproject.org/rpms/grub2.git
synced 2024-11-24 14:32:58 +00:00
a5db5fecf6
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>
105 lines
3.5 KiB
Diff
105 lines
3.5 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Dimitri John Ledkov <xnox@ubuntu.com>
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Date: Wed, 22 Jul 2020 11:31:43 +0100
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Subject: [PATCH] linuxefi: fail kernel validation without shim protocol.
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If certificates that signed grub are installed into db, grub can be
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booted directly. It will then boot any kernel without signature
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validation. The booted kernel will think it was booted in secureboot
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mode and will implement lockdown, yet it could have been tampered.
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This version of the patch skips calling verification, when booted
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without secureboot. And is indented with gnu ident.
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CVE-2020-15705
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Reported-by: Mathieu Trudel-Lapierre <cyphermox@ubuntu.com>
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Signed-off-by: Dimitri John Ledkov <xnox@ubuntu.com>
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---
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grub-core/loader/arm64/linux.c | 12 ++++++++----
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grub-core/loader/efi/chainloader.c | 1 +
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grub-core/loader/efi/linux.c | 1 +
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grub-core/loader/i386/efi/linux.c | 14 +++++++++-----
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4 files changed, 19 insertions(+), 9 deletions(-)
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diff --git a/grub-core/loader/arm64/linux.c b/grub-core/loader/arm64/linux.c
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index 8791b35b6fe..a18c4874c4f 100644
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--- a/grub-core/loader/arm64/linux.c
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+++ b/grub-core/loader/arm64/linux.c
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@@ -383,11 +383,15 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
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grub_dprintf ("linux", "kernel @ %p\n", kernel_addr);
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- rc = grub_linuxefi_secure_validate (kernel_addr, kernel_size);
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- if (rc < 0)
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+ if (grub_efi_secure_boot ())
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{
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- grub_error (GRUB_ERR_INVALID_COMMAND, N_("%s has invalid signature"), argv[0]);
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- goto fail;
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+ rc = grub_linuxefi_secure_validate (kernel_addr, kernel_size);
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+ if (rc <= 0)
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+ {
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+ grub_error (GRUB_ERR_INVALID_COMMAND,
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+ N_("%s has invalid signature"), argv[0]);
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+ goto fail;
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+ }
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}
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pe = (void *)((unsigned long)kernel_addr + lh.hdr_offset);
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diff --git a/grub-core/loader/efi/chainloader.c b/grub-core/loader/efi/chainloader.c
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index 3dfa41bb49d..26f4fa9dc6a 100644
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--- a/grub-core/loader/efi/chainloader.c
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+++ b/grub-core/loader/efi/chainloader.c
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@@ -1083,6 +1083,7 @@ grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)),
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return 0;
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}
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+ // -1 fall-through to fail
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fail:
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if (dev)
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diff --git a/grub-core/loader/efi/linux.c b/grub-core/loader/efi/linux.c
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index e09f824862b..927d89a90d7 100644
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--- a/grub-core/loader/efi/linux.c
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+++ b/grub-core/loader/efi/linux.c
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@@ -33,6 +33,7 @@ struct grub_efi_shim_lock
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};
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typedef struct grub_efi_shim_lock grub_efi_shim_lock_t;
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+// Returns 1 on success, -1 on error, 0 when not available
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int
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grub_linuxefi_secure_validate (void *data, grub_uint32_t size)
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{
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diff --git a/grub-core/loader/i386/efi/linux.c b/grub-core/loader/i386/efi/linux.c
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index c0a98d152ff..bf7ceca10ff 100644
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--- a/grub-core/loader/i386/efi/linux.c
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+++ b/grub-core/loader/i386/efi/linux.c
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@@ -30,6 +30,7 @@
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#include <grub/cpu/efi/memory.h>
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#include <grub/tpm.h>
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#include <grub/safemath.h>
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+#include <grub/efi/sb.h>
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GRUB_MOD_LICENSE ("GPLv3+");
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@@ -307,12 +308,15 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
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goto fail;
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}
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- rc = grub_linuxefi_secure_validate (kernel, filelen);
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- if (rc < 0)
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+ if (grub_efi_secure_boot ())
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{
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- grub_error (GRUB_ERR_INVALID_COMMAND, N_("%s has invalid signature"),
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- argv[0]);
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- goto fail;
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+ rc = grub_linuxefi_secure_validate (kernel, filelen);
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+ if (rc <= 0)
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+ {
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+ grub_error (GRUB_ERR_INVALID_COMMAND,
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+ N_("%s has invalid signature"), argv[0]);
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+ goto fail;
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+ }
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}
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lh = (struct linux_i386_kernel_header *)kernel;
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