Re: [PATCH v2 09/11] ima: Move validation of the keyrings conditional into ima_validate_rule()
From: Lakshmi Ramasubramanian <hidden>
Date: 2020-06-27 23:49:50
Also in:
linux-integrity, lkml
On 6/26/20 3:38 PM, Tyler Hicks wrote:
Use ima_validate_rule() to ensure that the combination of a hook function and the keyrings conditional is valid and that the keyrings conditional is not specified without an explicit KEY_CHECK func conditional. This is a code cleanup and has no user-facing change.
In addition to checking for func=KEY_CHECK and the keyrings conditional, the patch also validates the flags for other IMA hooks (such as KEXEC_KERNEL_CHECK, POLICY_CHECK, etc.) Would be good to mention that in the patch description. -lakshmi
quoted hunk ↗ jump to hunk
Signed-off-by: Tyler Hicks <redacted> --- * v2 - Allowed IMA_DIGSIG_REQUIRED, IMA_PERMIT_DIRECTIO, IMA_MODSIG_ALLOWED, and IMA_CHECK_BLACKLIST conditionals to be present in the rule entry flags for non-buffer hook functions. security/integrity/ima/ima_policy.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 8cdca2399d59..43d49ad958fb 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c@@ -1000,6 +1000,15 @@ static bool ima_validate_rule(struct ima_rule_entry *entry) case KEXEC_KERNEL_CHECK: case KEXEC_INITRAMFS_CHECK: case POLICY_CHECK: + if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC | + IMA_UID | IMA_FOWNER | IMA_FSUUID | + IMA_INMASK | IMA_EUID | IMA_PCR | + IMA_FSNAME | IMA_DIGSIG_REQUIRED | + IMA_PERMIT_DIRECTIO | + IMA_MODSIG_ALLOWED | + IMA_CHECK_BLACKLIST)) + return false; + break; case KEXEC_CMDLINE: if (entry->action & ~(MEASURE | DONT_MEASURE))@@ -1027,7 +1036,8 @@ static bool ima_validate_rule(struct ima_rule_entry *entry) default: return false; } - } + } else if (entry->flags & IMA_KEYRINGS) + return false; return true; }@@ -1209,7 +1219,6 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) keyrings_len = strlen(args[0].from) + 1; if ((entry->keyrings) || - (entry->func != KEY_CHECK) || (keyrings_len < 2)) { result = -EINVAL; break;