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| author | Matthew Garrett <matthewgarrett@google.com> | 2019-08-19 17:18:04 -0700 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2019-08-19 21:54:17 -0700 |
| commit | 1957a85b0032a81e6482ca4aab883643b8dae06e (patch) | |
| tree | 5adf9fd932190f269677c6a29090ebbec6569a6a | |
| parent | ccbd54ff54e8b1880456b81c4aea352ebe208843 (diff) | |
| download | linux-stable-1957a85b0032a81e6482ca4aab883643b8dae06e.tar.gz linux-stable-1957a85b0032a81e6482ca4aab883643b8dae06e.tar.bz2 linux-stable-1957a85b0032a81e6482ca4aab883643b8dae06e.zip | |
efi: Restrict efivar_ssdt_load when the kernel is locked down
efivar_ssdt_load allows the kernel to import arbitrary ACPI code from an
EFI variable, which gives arbitrary code execution in ring 0. Prevent
that when the kernel is locked down.
Signed-off-by: Matthew Garrett <mjg59@google.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: linux-efi@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
| -rw-r--r-- | drivers/firmware/efi/efi.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 4b7cf7bc0ded..5f98374f77f4 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -30,6 +30,7 @@ #include <linux/acpi.h> #include <linux/ucs2_string.h> #include <linux/memblock.h> +#include <linux/security.h> #include <asm/early_ioremap.h> @@ -241,6 +242,11 @@ static void generic_ops_unregister(void) static char efivar_ssdt[EFIVAR_SSDT_NAME_MAX] __initdata; static int __init efivar_ssdt_setup(char *str) { + int ret = security_locked_down(LOCKDOWN_ACPI_TABLES); + + if (ret) + return ret; + if (strlen(str) < sizeof(efivar_ssdt)) memcpy(efivar_ssdt, str, strlen(str)); else |