[PATCH V4 09/10] capabilities: fix logic for effective root or real root

Richard Guy Briggs rgb at redhat.com
Tue Sep 5 06:46:09 UTC 2017

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

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

Ref: commit 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 <rgb at redhat.com>
Reviewed-by: Serge Hallyn <serge at hallyn.com>
Acked-by: James Morris <james.l.morris at oracle.com>
 security/commoncap.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/security/commoncap.c b/security/commoncap.c
index 7e8041d..759f3fa 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -532,7 +532,7 @@ 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 were already root
  *   3) root is supposed to have all caps (SECURE_NOROOT)
  * Since this is just a normal root execing a process.
@@ -545,8 +545,7 @@ 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)) &&
 		ret = true;
 	return ret;

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