[PATCH V4 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>
Reviewed-by: Serge Hallyn <serge(a)hallyn.com>
Acked-by: James Morris <james.l.morris(a)oracle.com>
---
security/commoncap.c | 28 ++++++++++++++++++++++------
1 files changed, 22 insertions(+), 6 deletions(-)
diff --git a/security/commoncap.c b/security/commoncap.c
index 1904f49..d37ebec 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -474,6 +474,15 @@ 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); }
+
static void handle_privileged_root(struct linux_binprm *bprm, bool has_fcap,
bool *effective, kuid_t root_uid)
{
@@ -485,7 +494,7 @@ 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;
}
@@ -496,12 +505,12 @@ 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) || 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;
}
@@ -511,6 +520,13 @@ 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
@@ -548,7 +564,7 @@ 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) ||
@@ -602,7 +618,7 @@ 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)
@@ -619,7 +635,7 @@ 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;
--
1.7.1