From: Richard Guy Briggs <rgb@redhat.com>
To: linux-security-module@vger.kernel.org, linux-audit@redhat.com,
linux-kernel@vger.kernel.org
Cc: Richard Guy Briggs <rgb@redhat.com>,
Kees Cook <keescook@chromium.org>,
Andy Lutomirski <luto@kernel.org>,
"Serge E . Hallyn" <serge.hallyn@ubuntu.com>,
James Morris <james.l.morris@oracle.com>,
Paul Moore <pmoore@redhat.com>, Steve Grubb <sgrubb@redhat.com>,
Eric Paris <eparis@redhat.com>
Subject: [PATCH GHAK16 V5 05/10] capabilities: use intuitive names for id changes
Date: Wed, 11 Oct 2017 20:57:09 -0400 [thread overview]
Message-ID: <b4f35f618c9c937ae3bea4f3e1677f521115e874.1507769413.git.rgb@redhat.com> (raw)
In-Reply-To: <cover.1507769413.git.rgb@redhat.com>
In-Reply-To: <cover.1507769413.git.rgb@redhat.com>
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@redhat.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Acked-by: Kees Cook <keescook@chromium.org>
Okay-ished-by: Paul Moore <paul@paul-moore.com>
---
security/commoncap.c | 28 ++++++++++++++++++++++------
1 file changed, 22 insertions(+), 6 deletions(-)
diff --git a/security/commoncap.c b/security/commoncap.c
index 9b8a6e7..421f743 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -697,6 +697,15 @@ 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); }
+
/*
* 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;
--
1.8.3.1
next prev parent reply other threads:[~2017-10-12 0:59 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-12 0:57 [PATCH GHAK16 V5 00/10] capabilities: do not audit log BPRM_FCAPS on set*id Richard Guy Briggs
2017-10-12 0:57 ` [PATCH GHAK16 V5 01/10] capabilities: factor out cap_bprm_set_creds privileged root Richard Guy Briggs
2017-10-12 0:57 ` [PATCH GHAK16 V5 02/10] capabilities: intuitive names for cap gain status Richard Guy Briggs
2017-10-12 0:57 ` [PATCH GHAK16 V5 03/10] capabilities: rename has_cap to has_fcap Richard Guy Briggs
2017-10-12 0:57 ` [PATCH GHAK16 V5 04/10] capabilities: use root_priveleged inline to clarify logic Richard Guy Briggs
2017-10-12 0:57 ` Richard Guy Briggs [this message]
2017-10-12 0:57 ` [PATCH GHAK16 V5 06/10] capabilities: move audit log decision to function Richard Guy Briggs
2017-10-12 0:57 ` [PATCH GHAK16 V5 07/10] capabilities: remove a layer of conditional logic Richard Guy Briggs
2017-10-12 0:57 ` [PATCH GHAK16 V5 08/10] capabilities: invert logic for clarity Richard Guy Briggs
2017-10-12 0:57 ` [PATCH GHAK16 V5 09/10] capabilities: fix logic for effective root or real root Richard Guy Briggs
2017-10-12 0:57 ` [PATCH GHAK16 V5 10/10] capabilities: audit log other surprising conditions Richard Guy Briggs
2017-10-19 13:08 ` [PATCH GHAK16 V5 00/10] capabilities: do not audit log BPRM_FCAPS on set*id Richard Guy Briggs
2017-10-20 1:29 ` James Morris
2017-10-20 2:34 ` Richard Guy Briggs
2017-10-20 5:15 ` James Morris
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