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Commit 81a6a012 authored by Richard Guy Briggs's avatar Richard Guy Briggs Committed by James Morris
Browse files

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: default avatarRichard Guy Briggs <rgb@redhat.com>
Reviewed-by: default avatarSerge Hallyn <serge@hallyn.com>
Acked-by: default avatarJames Morris <james.l.morris@oracle.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Okay-ished-by: default avatarPaul Moore <paul@paul-moore.com>
Signed-off-by: default avatarJames Morris <james.l.morris@oracle.com>
parent 9304b46c

security/commoncap.c

+22 −6
Original line number Diff line number Diff line
@@ -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;