Re: [PATCH] ima: Support euid keyword for buffer measurement
From: Lakshmi Ramasubramanian <hidden>
Date: 2021-07-06 19:27:55
Also in:
linux-integrity, lkml
On 7/5/2021 4:56 AM, Roberto Sassu wrote: Hi Roberto,
This patch makes the 'euid' keyword available for buffer measurement rules, in the same way as for other rules. Currently, there is only support for the 'uid' keyword. With this change, buffer measurement (or non-measurement) can depend also on the process effective UID.
Who (kernel component) will be using this? Maybe you could make this change as part of the patch set in which the above "euid" support will be used. thanks, -lakshmi
quoted hunk ↗ jump to hunk
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> --- security/integrity/ima/ima_policy.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index fd5d46e511f1..fdaa030fb04b 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c@@ -480,6 +480,16 @@ static bool ima_match_rule_data(struct ima_rule_entry *rule, if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid)) return false; + if (rule->flags & IMA_EUID) { + if (has_capability_noaudit(current, CAP_SETUID)) { + if (!rule->uid_op(cred->euid, rule->uid) + && !rule->uid_op(cred->suid, rule->uid) + && !rule->uid_op(cred->uid, rule->uid)) + return false; + } else if (!rule->uid_op(cred->euid, rule->uid)) + return false; + } + switch (rule->func) { case KEY_CHECK: if (!rule->keyrings)@@ -1153,7 +1163,7 @@ static bool ima_validate_rule(struct ima_rule_entry *entry) if (entry->action & ~(MEASURE | DONT_MEASURE)) return false; - if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_PCR | + if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_EUID | IMA_PCR | IMA_LABEL)) return false;