1 files changed, 22 insertions, 6 deletions

diff --git a/security/commoncap.c b/security/commoncap.c
index 9b8a6e79d858..421f7438d3c8 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -697,6 +697,15 @@ out:
 
 static inline bool root_privileged(void) { return !issecure(SECURE_NOROOT); }
 
+static inline bool __is_real(kuid_t uid, struct cred *cred)
+{ return uid_eq(cred->uid, uid); }
+
+static inline bool __is_eff(kuid_t uid, struct cred *cred)
+{ return uid_eq(cred->euid, uid); }
+
+static inline bool __is_suid(kuid_t uid, struct cred *cred)
+{ return !__is_real(uid, cred) && __is_eff(uid, cred); }
+
 /*
  * handle_privileged_root - Handle case of privileged root
  * @bprm: The execution parameters, including the proposed creds
@@ -722,7 +731,7 @@ static void handle_privileged_root(struct linux_binprm *bprm, bool has_fcap,
          * for a setuid root binary run by a non-root user.  Do set it
          * for a root user just to cause least surprise to an admin.
          */
-        if (has_fcap && !uid_eq(new->uid, root_uid) && uid_eq(new->euid, root_uid)) {
+        if (has_fcap && __is_suid(root_uid, new)) {
                 warn_setuid_and_fcaps_mixed(bprm->filename);
                 return;
         }
@@ -731,7 +740,7 @@ static void handle_privileged_root(struct linux_binprm *bprm, bool has_fcap,
          * executables under compatibility mode, we override the
          * capability sets for the file.
          */
-        if (uid_eq(new->euid, root_uid) || uid_eq(new->uid, root_uid)) {
+        if (__is_eff(root_uid, new) || __is_real(root_uid, new)) {
                 /* pP' = (cap_bset & ~0) | (pI & ~0) */
                 new->cap_permitted = cap_combine(old->cap_bset,
                                                  old->cap_inheritable);
@@ -739,7 +748,7 @@ static void handle_privileged_root(struct linux_binprm *bprm, bool has_fcap,
         /*
          * If only the real uid is 0, we do not set the effective bit.
          */
-        if (uid_eq(new->euid, root_uid))
+        if (__is_eff(root_uid, new))
                 *effective = true;
 }
 
@@ -749,6 +758,13 @@ static void handle_privileged_root(struct linux_binprm *bprm, bool has_fcap,
         !cap_issubset(cred->cap_##target, cred->cap_##source)
 #define __cap_full(field, cred) \
         cap_issubset(CAP_FULL_SET, cred->cap_##field)
+
+static inline bool __is_setuid(struct cred *new, const struct cred *old)
+{ return !uid_eq(new->euid, old->uid); }
+
+static inline bool __is_setgid(struct cred *new, const struct cred *old)
+{ return !gid_eq(new->egid, old->gid); }
+
 /**
  * cap_bprm_set_creds - Set up the proposed credentials for execve().
  * @bprm: The execution parameters, including the proposed creds
@@ -785,7 +801,7 @@ int cap_bprm_set_creds(struct linux_binprm *bprm)
          *
          * In addition, if NO_NEW_PRIVS, then ensure we get no new privs.
          */
-        is_setid = !uid_eq(new->euid, old->uid) || !gid_eq(new->egid, old->gid);
+        is_setid = __is_setuid(new, old) || __is_setgid(new, old);
 
         if ((is_setid || __cap_gained(permitted, new, old)) &&
             ((bprm->unsafe & ~LSM_UNSAFE_PTRACE) ||
@@ -839,7 +855,7 @@ int cap_bprm_set_creds(struct linux_binprm *bprm)
          */
         if (__cap_grew(effective, ambient, new)) {
                 if (!__cap_full(effective, new) ||
-                    !uid_eq(new->euid, root_uid) || !uid_eq(new->uid, root_uid) ||
+                    !__is_eff(root_uid, new) || !__is_real(root_uid, new) ||
                     !root_privileged()) {
                         ret = audit_log_bprm_fcaps(bprm, new, old);
                         if (ret < 0)
@@ -856,7 +872,7 @@ int cap_bprm_set_creds(struct linux_binprm *bprm)
         bprm->cap_elevated = 0;
         if (is_setid) {
                 bprm->cap_elevated = 1;
-        } else if (!uid_eq(new->uid, root_uid)) {
+        } else if (!__is_real(root_uid, new)) {
                 if (effective ||
                     __cap_grew(permitted, ambient, new))
                         bprm->cap_elevated = 1;