Add an LSM hook prior to allowing firmware sysfs fallback loading.
Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
Cc: Luis R. Rodriguez <mcgrof@xxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Changelog v4:
- call new LSM security_kernel_arg hook
Changelog v2:
- call security_kernel_read_blob()
- rename the READING_FIRMWARE_FALLBACK kernel_read_file_id enumeration to
READING_FIRMWARE_FALLBACK_SYSFS.
---
drivers/base/firmware_loader/fallback.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c
index 358354148dec..2443bda81631 100644
--- a/drivers/base/firmware_loader/fallback.c
+++ b/drivers/base/firmware_loader/fallback.c
@@ -651,6 +651,8 @@ static bool fw_force_sysfs_fallback(unsigned int opt_flags)
static bool fw_run_sysfs_fallback(unsigned int opt_flags)
{
+ int ret;
+
if (fw_fallback_config.ignore_sysfs_fallback) {
pr_info_once("Ignoring firmware sysfs fallback due to sysctl knob\n");
return false;
@@ -659,6 +661,11 @@ static bool fw_run_sysfs_fallback(unsigned int opt_flags)
if ((opt_flags & FW_OPT_NOFALLBACK))
return false;
+ /* Also permit LSMs and IMA to fail firmware sysfs fallback */
+ ret = security_kernel_load_data(LOADING_FIRMWARE);
+ if (ret < 0)
+ return ret;
+
return fw_force_sysfs_fallback(opt_flags);
}
--
2.7.5
