diff options
Diffstat (limited to 'meta/recipes-bsp/grub/files/CVE-2020-25632.patch')
| -rw-r--r-- | meta/recipes-bsp/grub/files/CVE-2020-25632.patch | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/meta/recipes-bsp/grub/files/CVE-2020-25632.patch b/meta/recipes-bsp/grub/files/CVE-2020-25632.patch new file mode 100644 index 0000000000..0b37c72f0f --- /dev/null +++ b/meta/recipes-bsp/grub/files/CVE-2020-25632.patch @@ -0,0 +1,90 @@ +From 7630ec5397fe418276b360f9011934b8c034936c Mon Sep 17 00:00:00 2001 +From: Javier Martinez Canillas <javierm@redhat.com> +Date: Tue, 29 Sep 2020 14:08:55 +0200 +Subject: [PATCH] dl: Only allow unloading modules that are not dependencies + +When a module is attempted to be removed its reference counter is always +decremented. This means that repeated rmmod invocations will cause the +module to be unloaded even if another module depends on it. + +This may lead to a use-after-free scenario allowing an attacker to execute +arbitrary code and by-pass the UEFI Secure Boot protection. + +While being there, add the extern keyword to some function declarations in +that header file. + +Fixes: CVE-2020-25632 + +Reported-by: Chris Coulson <chris.coulson@canonical.com> +Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> +Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> + +Upstream-Status: Backport [https://git.savannah.gnu.org/cgit/grub.git/commit/?id=7630ec5397fe418276b360f9011934b8c034936c] +CVE: CVE-2020-25632 +Signed-off-by: Marta Rybczynska <marta.rybczynska@huawei.com> +--- + grub-core/commands/minicmd.c | 7 +++++-- + grub-core/kern/dl.c | 9 +++++++++ + include/grub/dl.h | 8 +++++--- + 3 files changed, 19 insertions(+), 5 deletions(-) + +diff --git a/grub-core/commands/minicmd.c b/grub-core/commands/minicmd.c +index 6bbce3128..fa498931e 100644 +--- a/grub-core/commands/minicmd.c ++++ b/grub-core/commands/minicmd.c +@@ -140,8 +140,11 @@ grub_mini_cmd_rmmod (struct grub_command *cmd __attribute__ ((unused)), + if (grub_dl_is_persistent (mod)) + return grub_error (GRUB_ERR_BAD_ARGUMENT, "cannot unload persistent module"); + +- if (grub_dl_unref (mod) <= 0) +- grub_dl_unload (mod); ++ if (grub_dl_ref_count (mod) > 1) ++ return grub_error (GRUB_ERR_BAD_ARGUMENT, "cannot unload referenced module"); ++ ++ grub_dl_unref (mod); ++ grub_dl_unload (mod); + + return 0; + } +diff --git a/grub-core/kern/dl.c b/grub-core/kern/dl.c +index 48eb5e7b6..48f8a7907 100644 +--- a/grub-core/kern/dl.c ++++ b/grub-core/kern/dl.c +@@ -549,6 +549,15 @@ grub_dl_unref (grub_dl_t mod) + return --mod->ref_count; + } + ++int ++grub_dl_ref_count (grub_dl_t mod) ++{ ++ if (mod == NULL) ++ return 0; ++ ++ return mod->ref_count; ++} ++ + static void + grub_dl_flush_cache (grub_dl_t mod) + { +diff --git a/include/grub/dl.h b/include/grub/dl.h +index f03c03561..b3753c9ca 100644 +--- a/include/grub/dl.h ++++ b/include/grub/dl.h +@@ -203,9 +203,11 @@ grub_dl_t EXPORT_FUNC(grub_dl_load) (const char *name); + grub_dl_t grub_dl_load_core (void *addr, grub_size_t size); + grub_dl_t EXPORT_FUNC(grub_dl_load_core_noinit) (void *addr, grub_size_t size); + int EXPORT_FUNC(grub_dl_unload) (grub_dl_t mod); +-void grub_dl_unload_unneeded (void); +-int EXPORT_FUNC(grub_dl_ref) (grub_dl_t mod); +-int EXPORT_FUNC(grub_dl_unref) (grub_dl_t mod); ++extern void grub_dl_unload_unneeded (void); ++extern int EXPORT_FUNC(grub_dl_ref) (grub_dl_t mod); ++extern int EXPORT_FUNC(grub_dl_unref) (grub_dl_t mod); ++extern int EXPORT_FUNC(grub_dl_ref_count) (grub_dl_t mod); ++ + extern grub_dl_t EXPORT_VAR(grub_dl_head); + + #ifndef GRUB_UTIL +-- +2.33.0 + |