SELinux: Abstract use of cred security blob

Don't use the cred->security pointer directly.
Provide a helper function that provides the security blob pointer.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
[kees: adjusted for ordered init series]
Signed-off-by: Kees Cook <keescook@chromium.org>

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index c5d9fbbb5e5b69e319b88036062a5ed996792f87..beec1de5c2dae263f08a33c2fce800f53036aece 100644 (file)
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -226,7 +226,7 @@ static inline u32 cred_sid(const struct cred *cred)
 {
        const struct task_security_struct *tsec;
 
-       tsec = cred->security;
+       tsec = selinux_cred(cred);
        return tsec->sid;
 }
 
@@ -498,7 +498,7 @@ static int may_context_mount_sb_relabel(u32 sid,
                        struct superblock_security_struct *sbsec,
                        const struct cred *cred)
 {
-       const struct task_security_struct *tsec = cred->security;
+       const struct task_security_struct *tsec = selinux_cred(cred);
        int rc;
 
        rc = avc_has_perm(&selinux_state,
@@ -517,7 +517,7 @@ static int may_context_mount_inode_relabel(u32 sid,
                        struct superblock_security_struct *sbsec,
                        const struct cred *cred)
 {
-       const struct task_security_struct *tsec = cred->security;
+       const struct task_security_struct *tsec = selinux_cred(cred);
        int rc;
        rc = avc_has_perm(&selinux_state,
                          tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
@@ -1803,7 +1803,7 @@ static int may_create(struct inode *dir,
                      struct dentry *dentry,
                      u16 tclass)
 {
-       const struct task_security_struct *tsec = current_security();
+       const struct task_security_struct *tsec = selinux_cred(current_cred());
        struct inode_security_struct *dsec;
        struct superblock_security_struct *sbsec;
        u32 sid, newsid;
@@ -1825,7 +1825,7 @@ static int may_create(struct inode *dir,
        if (rc)
                return rc;
 
-       rc = selinux_determine_inode_label(current_security(), dir,
+       rc = selinux_determine_inode_label(selinux_cred(current_cred()), dir,
                                           &dentry->d_name, tclass, &newsid);
        if (rc)
                return rc;
@@ -2332,8 +2332,8 @@ static int selinux_bprm_set_creds(struct linux_binprm *bprm)
        if (bprm->called_set_creds)
                return 0;
 
-       old_tsec = current_security();
-       new_tsec = bprm->cred->security;
+       old_tsec = selinux_cred(current_cred());
+       new_tsec = selinux_cred(bprm->cred);
        isec = inode_security(inode);
 
        /* Default to the current task SID. */
@@ -2497,7 +2497,7 @@ static void selinux_bprm_committing_creds(struct linux_binprm *bprm)
        struct rlimit *rlim, *initrlim;
        int rc, i;
 
-       new_tsec = bprm->cred->security;
+       new_tsec = selinux_cred(bprm->cred);
        if (new_tsec->sid == new_tsec->osid)
                return;
 
@@ -2540,7 +2540,7 @@ static void selinux_bprm_committing_creds(struct linux_binprm *bprm)
  */
 static void selinux_bprm_committed_creds(struct linux_binprm *bprm)
 {
-       const struct task_security_struct *tsec = current_security();
+       const struct task_security_struct *tsec = selinux_cred(current_cred());
        struct itimerval itimer;
        u32 osid, sid;
        int rc, i;
@@ -2777,7 +2777,7 @@ static int selinux_dentry_init_security(struct dentry *dentry, int mode,
        u32 newsid;
        int rc;
 
-       rc = selinux_determine_inode_label(current_security(),
+       rc = selinux_determine_inode_label(selinux_cred(current_cred()),
                                           d_inode(dentry->d_parent), name,
                                           inode_mode_to_security_class(mode),
                                           &newsid);
@@ -2797,14 +2797,14 @@ static int selinux_dentry_create_files_as(struct dentry *dentry, int mode,
        int rc;
        struct task_security_struct *tsec;
 
-       rc = selinux_determine_inode_label(old->security,
+       rc = selinux_determine_inode_label(selinux_cred(old),
                                           d_inode(dentry->d_parent), name,
                                           inode_mode_to_security_class(mode),
                                           &newsid);
        if (rc)
                return rc;
 
-       tsec = new->security;
+       tsec = selinux_cred(new);
        tsec->create_sid = newsid;
        return 0;
 }
@@ -2814,7 +2814,7 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
                                       const char **name,
                                       void **value, size_t *len)
 {
-       const struct task_security_struct *tsec = current_security();
+       const struct task_security_struct *tsec = selinux_cred(current_cred());
        struct superblock_security_struct *sbsec;
        u32 newsid, clen;
        int rc;
@@ -2824,7 +2824,7 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
 
        newsid = tsec->create_sid;
 
-       rc = selinux_determine_inode_label(current_security(),
+       rc = selinux_determine_inode_label(selinux_cred(current_cred()),
                dir, qstr,
                inode_mode_to_security_class(inode->i_mode),
                &newsid);
@@ -3286,7 +3286,7 @@ static int selinux_inode_copy_up(struct dentry *src, struct cred **new)
                        return -ENOMEM;
        }
 
-       tsec = new_creds->security;
+       tsec = selinux_cred(new_creds);
        /* Get label from overlay inode and set it in create_sid */
        selinux_inode_getsecid(d_inode(src), &sid);
        tsec->create_sid = sid;
@@ -3706,7 +3706,7 @@ static int selinux_cred_alloc_blank(struct cred *cred, gfp_t gfp)
  */
 static void selinux_cred_free(struct cred *cred)
 {
-       struct task_security_struct *tsec = cred->security;
+       struct task_security_struct *tsec = selinux_cred(cred);
 
        /*
         * cred->security == NULL if security_cred_alloc_blank() or
@@ -3726,7 +3726,7 @@ static int selinux_cred_prepare(struct cred *new, const struct cred *old,
        const struct task_security_struct *old_tsec;
        struct task_security_struct *tsec;
 
-       old_tsec = old->security;
+       old_tsec = selinux_cred(old);
 
        tsec = kmemdup(old_tsec, sizeof(struct task_security_struct), gfp);
        if (!tsec)
@@ -3741,8 +3741,8 @@ static int selinux_cred_prepare(struct cred *new, const struct cred *old,
  */
 static void selinux_cred_transfer(struct cred *new, const struct cred *old)
 {
-       const struct task_security_struct *old_tsec = old->security;
-       struct task_security_struct *tsec = new->security;
+       const struct task_security_struct *old_tsec = selinux_cred(old);
+       struct task_security_struct *tsec = selinux_cred(new);
 
        *tsec = *old_tsec;
 }
@@ -3758,7 +3758,7 @@ static void selinux_cred_getsecid(const struct cred *c, u32 *secid)
  */
 static int selinux_kernel_act_as(struct cred *new, u32 secid)
 {
-       struct task_security_struct *tsec = new->security;
+       struct task_security_struct *tsec = selinux_cred(new);
        u32 sid = current_sid();
        int ret;
 
@@ -3783,7 +3783,7 @@ static int selinux_kernel_act_as(struct cred *new, u32 secid)
 static int selinux_kernel_create_files_as(struct cred *new, struct inode *inode)
 {
        struct inode_security_struct *isec = inode_security(inode);
-       struct task_security_struct *tsec = new->security;
+       struct task_security_struct *tsec = selinux_cred(new);
        u32 sid = current_sid();
        int ret;
 
@@ -4332,7 +4332,7 @@ static int sock_has_perm(struct sock *sk, u32 perms)
 static int selinux_socket_create(int family, int type,
                                 int protocol, int kern)
 {
-       const struct task_security_struct *tsec = current_security();
+       const struct task_security_struct *tsec = selinux_cred(current_cred());
        u32 newsid;
        u16 secclass;
        int rc;
@@ -4352,7 +4352,7 @@ static int selinux_socket_create(int family, int type,
 static int selinux_socket_post_create(struct socket *sock, int family,
                                      int type, int protocol, int kern)
 {
-       const struct task_security_struct *tsec = current_security();
+       const struct task_security_struct *tsec = selinux_cred(current_cred());
        struct inode_security_struct *isec = inode_security_novalidate(SOCK_INODE(sock));
        struct sk_security_struct *sksec;
        u16 sclass = socket_type_to_security_class(family, type, protocol);
@@ -5233,7 +5233,7 @@ static int selinux_secmark_relabel_packet(u32 sid)
        const struct task_security_struct *__tsec;
        u32 tsid;
 
-       __tsec = current_security();
+       __tsec = selinux_cred(current_cred());
        tsid = __tsec->sid;
 
        return avc_has_perm(&selinux_state,
@@ -6170,7 +6170,7 @@ static int selinux_getprocattr(struct task_struct *p,
        unsigned len;
 
        rcu_read_lock();
-       __tsec = __task_cred(p)->security;
+       __tsec = selinux_cred(__task_cred(p));
 
        if (current != p) {
                error = avc_has_perm(&selinux_state,
@@ -6293,7 +6293,7 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
           operation.  See selinux_bprm_set_creds for the execve
           checks and may_create for the file creation checks. The
           operation will then fail if the context is not permitted. */
-       tsec = new->security;
+       tsec = selinux_cred(new);
        if (!strcmp(name, "exec")) {
                tsec->exec_sid = sid;
        } else if (!strcmp(name, "fscreate")) {
@@ -6422,7 +6422,7 @@ static int selinux_key_alloc(struct key *k, const struct cred *cred,
        if (!ksec)
                return -ENOMEM;
 
-       tsec = cred->security;
+       tsec = selinux_cred(cred);
        if (tsec->keycreate_sid)
                ksec->sid = tsec->keycreate_sid;
        else

diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h
index cc5e26b0161b462108e6261a4e4a87cfafccf934..734b6833bdff0a08c4a0c5137f15ee756ce96ecd 100644 (file)
--- a/security/selinux/include/objsec.h
+++ b/security/selinux/include/objsec.h
@@ -158,4 +158,9 @@ struct bpf_security_struct {
        u32 sid;  /*SID of bpf obj creater*/
 };
 
+static inline struct task_security_struct *selinux_cred(const struct cred *cred)
+{
+       return cred->security;
+}
+
 #endif /* _SELINUX_OBJSEC_H_ */

diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c
index bd7d18bdb147a8cad2003a41db60a94a19444fb4..7c57cb7e4146c9b56d7dd40a086c3eaecf5fca77 100644 (file)
--- a/security/selinux/xfrm.c
+++ b/security/selinux/xfrm.c
@@ -79,7 +79,7 @@ static int selinux_xfrm_alloc_user(struct xfrm_sec_ctx **ctxp,
                                   gfp_t gfp)
 {
        int rc;
-       const struct task_security_struct *tsec = current_security();
+       const struct task_security_struct *tsec = selinux_cred(current_cred());
        struct xfrm_sec_ctx *ctx = NULL;
        u32 str_len;
 
@@ -138,7 +138,7 @@ static void selinux_xfrm_free(struct xfrm_sec_ctx *ctx)
  */
 static int selinux_xfrm_delete(struct xfrm_sec_ctx *ctx)
 {
-       const struct task_security_struct *tsec = current_security();
+       const struct task_security_struct *tsec = selinux_cred(current_cred());
 
        if (!ctx)
                return 0;