Messages in this thread Patch in this message | | | From | Sven Van Asbroeck <> | Subject | [PATCH] firmware: improve LSM/IMA security behaviour | Date | Mon, 17 Jun 2019 14:23:54 -0400 |
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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> --- 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 f962488546b6..103b5d37fa86 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); } -- 2.17.1
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