From d906c10d8a31654cb9167c9a2ebc7d3e43820bad Mon Sep 17 00:00:00 2001 From: Matthew Garrett Date: Mon, 8 Jan 2018 13:36:20 -0800 Subject: IMA: Support using new creds in appraisal policy The existing BPRM_CHECK functionality in IMA validates against the credentials of the existing process, not any new credentials that the child process may transition to. Add an additional CREDS_CHECK target and refactor IMA to pass the appropriate creds structure. In ima_bprm_check(), check with both the existing process credentials and the credentials that will be committed when the new process is started. This will not change behaviour unless the system policy is extended to include CREDS_CHECK targets - BPRM_CHECK will continue to check the same credentials that it did previously. After this patch, an IMA policy rule along the lines of: measure func=CREDS_CHECK subj_type=unconfined_t will trigger if a process is executed and runs as unconfined_t, ignoring the context of the parent process. This is in contrast to: measure func=BPRM_CHECK subj_type=unconfined_t which will trigger if the process that calls exec() is already executing in unconfined_t, ignoring the context that the child process executes into. Signed-off-by: Matthew Garrett Signed-off-by: Mimi Zohar Changelog: - initialize ima_creds_status --- security/integrity/ima/ima_api.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'security/integrity/ima/ima_api.c') diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index 08fe405338e1..33b4458cdbef 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -158,6 +158,8 @@ err_out: /** * ima_get_action - appraise & measure decision based on policy. * @inode: pointer to inode to measure + * @cred: pointer to credentials structure to validate + * @secid: secid of the task being validated * @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXEC, * MAY_APPEND) * @func: caller identifier @@ -166,20 +168,21 @@ err_out: * The policy is defined in terms of keypairs: * subj=, obj=, type=, func=, mask=, fsmagic= * subj,obj, and type: are LSM specific. - * func: FILE_CHECK | BPRM_CHECK | MMAP_CHECK | MODULE_CHECK + * func: FILE_CHECK | BPRM_CHECK | CREDS_CHECK | MMAP_CHECK | MODULE_CHECK * mask: contains the permission mask * fsmagic: hex value * * Returns IMA_MEASURE, IMA_APPRAISE mask. * */ -int ima_get_action(struct inode *inode, int mask, enum ima_hooks func, int *pcr) +int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid, + int mask, enum ima_hooks func, int *pcr) { int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE | IMA_HASH; flags &= ima_policy_flag; - return ima_match_policy(inode, func, mask, flags, pcr); + return ima_match_policy(inode, cred, secid, func, mask, flags, pcr); } /* -- cgit v1.2.3