This is a note to let you know that I've just added the patch titled
firmware: improve LSM/IMA security behaviour
to my driver-core git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git
in the driver-core-testing branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will be merged to the driver-core-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From 2472d64af2d3561954e2f05365a67692bb852f2a Mon Sep 17 00:00:00 2001
From: Sven Van Asbroeck <thesven73@xxxxxxxxx>
Date: Mon, 17 Jun 2019 14:23:54 -0400
Subject: 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 <stable@xxxxxxxxxxxxxxx>
Cc: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
To: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Sven Van Asbroeck <TheSven73@xxxxxxxxx>
Reviewed-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
}
--
2.22.0
