From 2472d64af2d3561954e2f05365a67692bb852f2a Mon Sep 17 00:00:00 2001 From: Sven Van Asbroeck Date: Mon, 17 Jun 2019 14:23:54 -0400 Subject: [PATCH] firmware: improve LSM/IMA security behaviour 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 Cc: Mimi Zohar Cc: Kees Cook To: Luis Chamberlain Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: linux-kernel@vger.kernel.org Signed-off-by: Sven Van Asbroeck Reviewed-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman --- drivers/base/firmware_loader/fallback.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c index b5cd96fd0e77..29becea1910d 100644 --- 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 fw_opt opt_flags) /* 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); } -- 2.30.2