Thread (57 messages) 57 messages, 7 authors, 2017-09-05
STALE3186d REVIEWED: 1 (0M)

[PATCH V3 09/10] capabilities: fix logic for effective root or real root

From: jmorris@namei.org (James Morris)
Date: 2017-08-25 05:48:45

On Wed, 23 Aug 2017, Richard Guy Briggs wrote:
Now that the logic is inverted, it is much easier to see that both real root
and effective root conditions had to be met to avoid printing the BPRM_FCAPS
record with audit syscalls.  This meant that any setuid root applications would
print a full BPRM_FCAPS record when it wasn't necessary, cluttering the event
output, since the SYSCALL and PATH records indicated the presence of the setuid
bit and effective root user id.

Require only one of effective root or real root to avoid printing the
unnecessary record.

Ref: 3fc689e96c0c (Add audit_log_bprm_fcaps/AUDIT_BPRM_FCAPS)
See: https://github.com/linux-audit/audit-kernel/issues/16

Signed-off-by: Richard Guy Briggs <redacted>
---
 security/commoncap.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

Acked-by: James Morris <redacted>

quoted hunk ↗ jump to hunk
diff --git a/security/commoncap.c b/security/commoncap.c
index eb2da69..49cce06 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -540,7 +540,7 @@ static inline bool is_setgid(struct cred *new, const struct cred *old)
  *
  * We do not bother to audit if 3 things are true:
  *   1) cap_effective has all caps
- *   2) we are root
+ *   2) we became root *OR* are root
  *   3) root is supposed to have all caps (SECURE_NOROOT)
  * Since this is just a normal root execing a process.
  *
@@ -553,8 +553,8 @@ static inline bool nonroot_raised_pE(struct cred *cred, kuid_t root)
 
 	if (cap_grew(effective, ambient, cred) &&
 	    !(cap_full(effective, cred) &&
-	      is_eff(root, cred) &&
-	      is_real(root, cred) &&
+	      (is_eff(root, cred) ||
+	       is_real(root, cred)) &&
 	      root_privileged()))
 		ret = true;
 	return ret;
-- 
James Morris
[off-list ref]

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