[PATCH V3 05/10] capabilities: use intuitive names for id changes
Introduce a number of inlines to make the use of the negation of
uid_eq() easier to read and analyse.
Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com>
---
security/commoncap.c | 26 +++++++++++++++++++++-----
1 files changed, 21 insertions(+), 5 deletions(-)
diff --git a/security/commoncap.c b/security/commoncap.c
index 36c38a1..1af7dec 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -483,6 +483,15 @@ static int get_file_caps(struct linux_binprm *bprm, bool *effective,
bool *has_f
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); }
+
void handle_privileged_root(struct linux_binprm *bprm, bool has_fcap, bool *effective,
kuid_t root_uid)
{
const struct cred *old = current_cred();
@@ -493,7 +502,7 @@ void handle_privileged_root(struct linux_binprm *bprm, bool has_fcap,
bool *effe
* 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;
}
@@ -504,12 +513,12 @@ void handle_privileged_root(struct linux_binprm *bprm, bool
has_fcap, bool *effe
*
* If only the real uid is 0, we do not set the effective bit.
*/
- 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);
}
- if (uid_eq(new->euid, root_uid))
+ if (is_eff(root_uid, new))
*effective = true;
}
@@ -519,6 +528,13 @@ void handle_privileged_root(struct linux_binprm *bprm, bool has_fcap,
bool *effe
!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
@@ -556,7 +572,7 @@ 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) ||
@@ -612,7 +628,7 @@ 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)
--
1.7.1