4.9-stable review patch. If anyone has any objections, please let me know.
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From: Roberto Sassu roberto.sassu@huawei.com
commit 020aae3ee58c1af0e7ffc4e2cc9fe4dc630338cb upstream.
Commit b65a9cfc2c38 ("Untangling ima mess, part 2: deal with counters") moved the call of ima_file_check() from may_open() to do_filp_open() at a point where the file descriptor is already opened.
This breaks the assumption made by IMA that file descriptors being closed belong to files whose access was granted by ima_file_check(). The consequence is that security.ima and security.evm are updated with good values, regardless of the current appraisal status.
For example, if a file does not have security.ima, IMA will create it after opening the file for writing, even if access is denied. Access to the file will be allowed afterwards.
Avoid this issue by checking the appraisal status before updating security.ima.
Signed-off-by: Roberto Sassu roberto.sassu@huawei.com Signed-off-by: Mimi Zohar zohar@linux.vnet.ibm.com Signed-off-by: James Morris james.l.morris@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- security/integrity/ima/ima_appraise.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -303,6 +303,9 @@ void ima_update_xattr(struct integrity_i if (iint->flags & IMA_DIGSIG) return;
+ if (iint->ima_file_status != INTEGRITY_PASS) + return; + rc = ima_collect_measurement(iint, file, NULL, 0, ima_hash_algo); if (rc < 0) return;