@@ -65,14 +65,11 @@ choice
help
Select the default IMA measurement template.
- The original 'ima' measurement list template contains a
- hash, defined as 20 bytes, and a null terminated pathname,
- limited to 255 characters. The 'ima-ng' measurement list
- template permits both larger hash digests and longer
- pathnames.
-
- config IMA_TEMPLATE
- bool "ima"
+ The 'ima-ng' measurement list template permits various hash
+ digests and long pathnames. The compiled default template
+ can be overwritten using the kernel command line
+ 'ima_template=' option.
+
config IMA_NG_TEMPLATE
bool "ima-ng (default)"
config IMA_SIG_TEMPLATE
@@ -82,7 +79,6 @@ endchoice
config IMA_DEFAULT_TEMPLATE
string
depends on IMA
- default "ima" if IMA_TEMPLATE
default "ima-ng" if IMA_NG_TEMPLATE
default "ima-sig" if IMA_SIG_TEMPLATE
@@ -102,19 +98,19 @@ choice
config IMA_DEFAULT_HASH_SHA256
bool "SHA256"
- depends on CRYPTO_SHA256=y && !IMA_TEMPLATE
+ depends on CRYPTO_SHA256=y
config IMA_DEFAULT_HASH_SHA512
bool "SHA512"
- depends on CRYPTO_SHA512=y && !IMA_TEMPLATE
+ depends on CRYPTO_SHA512=y
config IMA_DEFAULT_HASH_WP512
bool "WP512"
- depends on CRYPTO_WP512=y && !IMA_TEMPLATE
+ depends on CRYPTO_WP512=y
config IMA_DEFAULT_HASH_SM3
bool "SM3"
- depends on CRYPTO_SM3=y && !IMA_TEMPLATE
+ depends on CRYPTO_SM3=y
endchoice
config IMA_DEFAULT_HASH
It is discovered that allowing template "ima" as the compiled default would cause the following issue: the boot command line option "ima_hash=" must be behind "ima_template=", otherwise "ima_hash=" might be rejected. The root cause of this issue is that during the processing of ima_hash, we would try to check whether the hash algorithm is compatible with the template. If the template is not set at the moment we do the check, we check the algorithm against the compiled default template. If the complied default template is "ima", then we reject any hash algorithm other than sha1 and md5. For example, if the compiled default template is "ima", and the default algorithm is sha1 (which is the current default). In the cmdline, we put in "ima_hash=sha256 ima_template=ima-ng". The expected behavior would be that ima starts with ima-ng as the template and sha256 as the hash algorithm. However, during the processing of "ima_hash=", "ima_template=" has not been processed yet, and hash_setup would check the configured hash algorithm against the compiled default: ima, and reject sha256. So at the end, the hash algorithm that is actually used will be sha1. With template "ima" removed from the compiled default, we ensure that the default tempalte would at least be "ima-ng" which allows for basically any hash algorithm. Users who needs to use "ima" template could still do it by specifying "ima_template=ima" in boot command line. This change would not break the algorithm compatibility checking for IMA. Fixes: 4286587dccd43 ("ima: add Kconfig default measurement list template") Signed-off-by: GUO Zihua <guozihua@huawei.com> --- security/integrity/ima/Kconfig | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-)