kumquat-buildroot/boot/grub2/0004-commands-boot-Add-API-to-pass-context-to-loader.patch
Thomas Petazzoni 65c99394ff boot/grub2: backport fixes for numerous CVEs
Grub 2.06 is affected by a number of CVEs, which have been fixed in
the master branch of Grub, but are not yet part of any release (there
is a 2.12-rc1 release, but nothing else between 2.06 and 2.12-rc1).

So this patch backports the relevant fixes for CVE-2022-28736,
CVE-2022-28735, CVE-2021-3695, CVE-2021-3696, CVE-2021-3697,
CVE-2022-28733, CVE-2022-28734, CVE-2022-2601 and CVE-2022-3775.

It should be noted that CVE-2021-3695, CVE-2021-3696, CVE-2021-3697
are not reported as affecting Grub by our CVE matching logic because
the NVD database uses an incorrect CPE ID in those CVEs: it uses
"grub" as the product instead of "grub2" like all other CVEs for
grub. This issue has been reported to the NVD maintainers.

This requires backporting a lot of patches, but jumping from 2.06 to
2.12-rc1 implies getting 592 commits, which is quite a lot.

All Grub test cases are working fine:

  https://gitlab.com/tpetazzoni/buildroot/-/pipelines/984500585
  https://gitlab.com/tpetazzoni/buildroot/-/pipelines/984500679

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
[Arnout: fix check-package warning in patch 0002]
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>
2023-08-30 21:54:23 +02:00

166 lines
4.8 KiB
Diff

From 8b6336696d93b51703c2015eff3e2d8a02145e43 Mon Sep 17 00:00:00 2001
From: Chris Coulson <chris.coulson@canonical.com>
Date: Tue, 5 Apr 2022 10:58:28 +0100
Subject: [PATCH] commands/boot: Add API to pass context to loader
Loaders rely on global variables for saving context which is consumed
in the boot hook and freed in the unload hook. In the case where a loader
command is executed twice, calling grub_loader_set() a second time executes
the unload hook, but in some cases this runs when the loader's global
context has already been updated, resulting in the updated context being
freed and potential use-after-free bugs when the boot hook is subsequently
called.
This adds a new API, grub_loader_set_ex(), which allows a loader to specify
context that is passed to its boot and unload hooks. This is an alternative
to requiring that loaders call grub_loader_unset() before mutating their
global context.
Signed-off-by: Chris Coulson <chris.coulson@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Upstream: 14ceb3b3ff6db664649138442b6562c114dcf56e
[Thomas: needed to backport 04c86e0bb7b58fc2f913f798cdb18934933e532d,
which fixes CVE-2022-28736]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
---
grub-core/commands/boot.c | 66 ++++++++++++++++++++++++++++++++++-----
include/grub/loader.h | 5 +++
2 files changed, 63 insertions(+), 8 deletions(-)
diff --git a/grub-core/commands/boot.c b/grub-core/commands/boot.c
index bbca81e94..61514788e 100644
--- a/grub-core/commands/boot.c
+++ b/grub-core/commands/boot.c
@@ -27,10 +27,20 @@
GRUB_MOD_LICENSE ("GPLv3+");
-static grub_err_t (*grub_loader_boot_func) (void);
-static grub_err_t (*grub_loader_unload_func) (void);
+static grub_err_t (*grub_loader_boot_func) (void *context);
+static grub_err_t (*grub_loader_unload_func) (void *context);
+static void *grub_loader_context;
static int grub_loader_flags;
+struct grub_simple_loader_hooks
+{
+ grub_err_t (*boot) (void);
+ grub_err_t (*unload) (void);
+};
+
+/* Don't heap allocate this to avoid making grub_loader_set() fallible. */
+static struct grub_simple_loader_hooks simple_loader_hooks;
+
struct grub_preboot
{
grub_err_t (*preboot_func) (int);
@@ -44,6 +54,29 @@ static int grub_loader_loaded;
static struct grub_preboot *preboots_head = 0,
*preboots_tail = 0;
+static grub_err_t
+grub_simple_boot_hook (void *context)
+{
+ struct grub_simple_loader_hooks *hooks;
+
+ hooks = (struct grub_simple_loader_hooks *) context;
+ return hooks->boot ();
+}
+
+static grub_err_t
+grub_simple_unload_hook (void *context)
+{
+ struct grub_simple_loader_hooks *hooks;
+ grub_err_t ret;
+
+ hooks = (struct grub_simple_loader_hooks *) context;
+
+ ret = hooks->unload ();
+ grub_memset (hooks, 0, sizeof (*hooks));
+
+ return ret;
+}
+
int
grub_loader_is_loaded (void)
{
@@ -110,28 +143,45 @@ grub_loader_unregister_preboot_hook (struct grub_preboot *hnd)
}
void
-grub_loader_set (grub_err_t (*boot) (void),
- grub_err_t (*unload) (void),
- int flags)
+grub_loader_set_ex (grub_err_t (*boot) (void *context),
+ grub_err_t (*unload) (void *context),
+ void *context,
+ int flags)
{
if (grub_loader_loaded && grub_loader_unload_func)
- grub_loader_unload_func ();
+ grub_loader_unload_func (grub_loader_context);
grub_loader_boot_func = boot;
grub_loader_unload_func = unload;
+ grub_loader_context = context;
grub_loader_flags = flags;
grub_loader_loaded = 1;
}
+void
+grub_loader_set (grub_err_t (*boot) (void),
+ grub_err_t (*unload) (void),
+ int flags)
+{
+ grub_loader_set_ex (grub_simple_boot_hook,
+ grub_simple_unload_hook,
+ &simple_loader_hooks,
+ flags);
+
+ simple_loader_hooks.boot = boot;
+ simple_loader_hooks.unload = unload;
+}
+
void
grub_loader_unset(void)
{
if (grub_loader_loaded && grub_loader_unload_func)
- grub_loader_unload_func ();
+ grub_loader_unload_func (grub_loader_context);
grub_loader_boot_func = 0;
grub_loader_unload_func = 0;
+ grub_loader_context = 0;
grub_loader_loaded = 0;
}
@@ -158,7 +208,7 @@ grub_loader_boot (void)
return err;
}
}
- err = (grub_loader_boot_func) ();
+ err = (grub_loader_boot_func) (grub_loader_context);
for (cur = preboots_tail; cur; cur = cur->prev)
if (! err)
diff --git a/include/grub/loader.h b/include/grub/loader.h
index b20864282..97f231054 100644
--- a/include/grub/loader.h
+++ b/include/grub/loader.h
@@ -40,6 +40,11 @@ void EXPORT_FUNC (grub_loader_set) (grub_err_t (*boot) (void),
grub_err_t (*unload) (void),
int flags);
+void EXPORT_FUNC (grub_loader_set_ex) (grub_err_t (*boot) (void *context),
+ grub_err_t (*unload) (void *context),
+ void *context,
+ int flags);
+
/* Unset current loader, if any. */
void EXPORT_FUNC (grub_loader_unset) (void);
--
2.41.0