From: Randy Dunlap rdunlap@infradead.org
[ Upstream commit f2544f5e6c691679d56bb38637d2f347075b36fa ]
__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 string "evm=fix" causes an Unknown parameter message: Unknown kernel command line parameters "BOOT_IMAGE=/boot/bzImage-517rc5 evm=fix", will be passed to user space.
and that string is 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 evm=fix
With this change, using "evm=fix" acts as expected and an invalid option ("evm=evm") causes a warning to be printed: evm: invalid "evm" mode but init's environment is not polluted with this string, as expected.
Fixes: 7102ebcd65c1 ("evm: permit only valid security.evm xattrs to be updated") Signed-off-by: Randy Dunlap rdunlap@infradead.org Reported-by: Igor Zhbanov i.zhbanov@omprussia.ru Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru Signed-off-by: Mimi Zohar zohar@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- security/integrity/evm/evm_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 08f907382c61..7d87772f0ce6 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -86,7 +86,7 @@ static int __init evm_set_fixmode(char *str) else pr_err("invalid "%s" mode", str);
- return 0; + return 1; } __setup("evm=", evm_set_fixmode);