[PATCH 5.16 0545/1017] TOMOYO: fix __setup handlers return values

Greg Kroah-Hartman
2022-04-05T12:53:20Z

From: Randy Dunlap <rdunlap@infradead.org>

[ Upstream commit 39844b7e3084baecef52d1498b5fa81afa2cefa9 ]

__setup() handlers should return 1 if the parameter is handled.
Returning 0 causes the entire string to be added to init's
environment strings (limited to 32 strings), unnecessarily polluting it.

Using the documented strings "TOMOYO_loader=string1" and
"TOMOYO_trigger=string2" causes an Unknown parameter message:
Unknown kernel command line parameters
"BOOT_IMAGE=/boot/bzImage-517rc5 TOMOYO_loader=string1 \
TOMOYO_trigger=string2", will be passed to user space.

and these strings are added to init's environment string space:
Run /sbin/init as init process
with arguments:
/sbin/init
with environment:
HOME=/
TERM=linux
BOOT_IMAGE=/boot/bzImage-517rc5
TOMOYO_loader=string1
TOMOYO_trigger=string2

With this change, these __setup handlers act as expected,
and init's environment is not polluted with these strings.

Fixes: 0e4ae0e0dec63 ("TOMOYO: Make several options configurable.")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru>
Link: https://lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Cc: James Morris <jmorris@namei.org>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: tomoyo-dev-en@lists.osdn.me
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
security/tomoyo/load_policy.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/security/tomoyo/load_policy.c b/security/tomoyo/load_policy.c
index 3445ae6fd479..363b65be87ab 100644
--- a/security/tomoyo/load_policy.c
+++ b/security/tomoyo/load_policy.c
@@ -24,7 +24,7 @@ static const char *tomoyo_loader;
static int __init tomoyo_loader_setup(char *str)
{
tomoyo_loader = str;
- return 0;
+ return 1;
}

__setup("TOMOYO_loader=", tomoyo_loader_setup);
@@ -64,7 +64,7 @@ static const char *tomoyo_trigger;
static int __init tomoyo_trigger_setup(char *str)
{
tomoyo_trigger = str;
- return 0;
+ return 1;
}

__setup("TOMOYO_trigger=", tomoyo_trigger_setup);
--
2.34.1