From: Sven Van Asbroeck thesven73@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 stable@vger.kernel.org Cc: Mimi Zohar zohar@linux.vnet.ibm.com Cc: Kees Cook keescook@chromium.org To: Luis Chamberlain mcgrof@kernel.org Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: "Rafael J. Wysocki" rafael@kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Sven Van Asbroeck TheSven73@gmail.com Reviewed-by: Mimi Zohar zohar@linux.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@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); }