From: Sven Van Asbroeck <thesve...@gmail.com>
commit 2472d64af2d3561954e2f05365a67692bb852f2a upstream.
The firmware loader queries if LSM/IMA permits it to load firmware
via the sysfs fallback. Unfortunately, the code does the opposite:
it expressly permits sysfs fw loading if security_kernel_load_data(
LOADING_FIRMWARE) returns -EACCES. This happens because a
zero-on-success return value is cast to a bool that's true on success.
Fix the return value handling so we get the correct behaviour.
Fixes: 6e852651f28e ("firmware: add call to LSM hook before firmware sysfs
fallback")
Cc: Stable <sta...@vger.kernel.org>
Cc: Mimi Zohar <zo...@linux.vnet.ibm.com>
Cc: Kees Cook <keesc...@chromium.org>
To: Luis Chamberlain <mcg...@kernel.org>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <raf...@kernel.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sven Van Asbroeck <thesve...@gmail.com>
Reviewed-by: Mimi Zohar <zo...@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/base/firmware_loader/fallback.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/base/firmware_loader/fallback.c
+++ b/drivers/base/firmware_loader/fallback.c
@@ -659,7 +659,7 @@ static bool fw_run_sysfs_fallback(enum f
/* Also permit LSMs and IMA to fail firmware sysfs fallback */
ret = security_kernel_load_data(LOADING_FIRMWARE);
if (ret < 0)
- return ret;
+ return false;
return fw_force_sysfs_fallback(opt_flags);
}
