selinux: switch to private struct selinux_mnt_opts

none of the convolutions needed, just 4 strings, TYVM...

Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 101 insertions, 161 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index caf7ca7abfc1..238907d69e8b 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -433,16 +433,17 @@ static void superblock_free_security(struct super_block *sb)
         kfree(sbsec);
 }
 
+struct selinux_mnt_opts {
+        const char *fscontext, *context, *rootcontext, *defcontext;
+};
+
 static void selinux_free_mnt_opts(void *mnt_opts)
 {
-        struct security_mnt_opts *opts = mnt_opts;
-        int i;
-
-        if (opts->mnt_opts)
-                for (i = 0; i < opts->num_mnt_opts; i++)
-                        kfree(opts->mnt_opts[i]);
-        kfree(opts->mnt_opts);
-        kfree(opts->mnt_opts_flags);
+        struct selinux_mnt_opts *opts = mnt_opts;
+        kfree(opts->fscontext);
+        kfree(opts->context);
+        kfree(opts->rootcontext);
+        kfree(opts->defcontext);
         kfree(opts);
 }
 
@@ -624,6 +625,17 @@ static int bad_option(struct superblock_security_struct *sbsec, char flag,
         return 0;
 }
 
+static int parse_sid(struct super_block *sb, const char *s, u32 *sid)
+{
+        int rc = security_context_str_to_sid(&selinux_state, s,
+                                             sid, GFP_KERNEL);
+        if (rc)
+                pr_warn("SELinux: security_context_str_to_sid"
+                       "(%s) failed for (dev %s, type %s) errno=%d\n",
+                       s, sb->s_id, sb->s_type->name, rc);
+        return rc;
+}
+
 /*
  * Allow filesystems with binary mount data to explicitly set mount point
  * labeling information.
@@ -634,22 +646,18 @@ static int selinux_set_mnt_opts(struct super_block *sb,
                                 unsigned long *set_kern_flags)
 {
         const struct cred *cred = current_cred();
-        int rc = 0, i;
         struct superblock_security_struct *sbsec = sb->s_security;
-        const char *name = sb->s_type->name;
         struct dentry *root = sbsec->sb->s_root;
+        struct selinux_mnt_opts *opts = mnt_opts;
         struct inode_security_struct *root_isec;
         u32 fscontext_sid = 0, context_sid = 0, rootcontext_sid = 0;
         u32 defcontext_sid = 0;
-        struct security_mnt_opts *opts = mnt_opts;
-        char **mount_options = opts ? opts->mnt_opts : NULL;
-        int *flags = opts ? opts->mnt_opts_flags : NULL;
-        int num_opts = opts ? opts->num_mnt_opts : 0;
+        int rc = 0;
 
         mutex_lock(&sbsec->lock);
 
         if (!selinux_state.initialized) {
-                if (!num_opts) {
+                if (!opts) {
                         /* Defer initialization until selinux_complete_init,
                            after the initial policy is loaded and the security
                            server is ready to handle calls. */
@@ -679,7 +687,7 @@ static int selinux_set_mnt_opts(struct super_block *sb,
          * will be used for both mounts)
          */
         if ((sbsec->flags & SE_SBINITIALIZED) && (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA)
-            && (num_opts == 0))
+            && !opts)
                 goto out;
 
         root_isec = backing_inode_security_novalidate(root);
@@ -689,68 +697,48 @@ static int selinux_set_mnt_opts(struct super_block *sb,
          * also check if someone is trying to mount the same sb more
          * than once with different security options.
          */
-        for (i = 0; i < num_opts; i++) {
-                u32 sid;
-
-                if (flags[i] == SBLABEL_MNT)
-                        continue;
-                rc = security_context_str_to_sid(&selinux_state,
-                                                 mount_options[i], &sid,
-                                                 GFP_KERNEL);
-                if (rc) {
-                        pr_warn("SELinux: security_context_str_to_sid"
-                               "(%s) failed for (dev %s, type %s) errno=%d\n",
-                               mount_options[i], sb->s_id, name, rc);
-                        goto out;
-                }
-                switch (flags[i]) {
-                case FSCONTEXT_MNT:
-                        fscontext_sid = sid;
-
+        if (opts) {
+                if (opts->fscontext) {
+                        rc = parse_sid(sb, opts->fscontext, &fscontext_sid);
+                        if (rc)
+                                goto out;
                         if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
                                         fscontext_sid))
                                 goto out_double_mount;
-
                         sbsec->flags |= FSCONTEXT_MNT;
-                        break;
-                case CONTEXT_MNT:
-                        context_sid = sid;
-
+                }
+                if (opts->context) {
+                        rc = parse_sid(sb, opts->context, &context_sid);
+                        if (rc)
+                                goto out;
                         if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
                                         context_sid))
                                 goto out_double_mount;
-
                         sbsec->flags |= CONTEXT_MNT;
-                        break;
-                case ROOTCONTEXT_MNT:
-                        rootcontext_sid = sid;
-
+                }
+                if (opts->rootcontext) {
+                        rc = parse_sid(sb, opts->rootcontext, &rootcontext_sid);
+                        if (rc)
+                                goto out;
                         if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
                                         rootcontext_sid))
                                 goto out_double_mount;
-
                         sbsec->flags |= ROOTCONTEXT_MNT;
-
-                        break;
-                case DEFCONTEXT_MNT:
-                        defcontext_sid = sid;
-
+                }
+                if (opts->defcontext) {
+                        rc = parse_sid(sb, opts->defcontext, &defcontext_sid);
+                        if (rc)
+                                goto out;
                         if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
                                         defcontext_sid))
                                 goto out_double_mount;
-
                         sbsec->flags |= DEFCONTEXT_MNT;
-
-                        break;
-                default:
-                        rc = -EINVAL;
-                        goto out;
                 }
         }
 
         if (sbsec->flags & SE_SBINITIALIZED) {
                 /* previously mounted with options, but not on this attempt? */
-                if ((sbsec->flags & SE_MNTMASK) && !num_opts)
+                if ((sbsec->flags & SE_MNTMASK) && !opts)
                         goto out_double_mount;
                 rc = 0;
                 goto out;
@@ -883,7 +871,8 @@ out:
 out_double_mount:
         rc = -EINVAL;
         pr_warn("SELinux: mount invalid.  Same superblock, different "
-               "security settings for (dev %s, type %s)\n", sb->s_id, name);
+               "security settings for (dev %s, type %s)\n", sb->s_id,
+               sb->s_type->name);
         goto out;
 }
 
@@ -998,20 +987,9 @@ out:
 static int selinux_parse_opts_str(char *options,
                                   void **mnt_opts)
 {
+        struct selinux_mnt_opts *opts = *mnt_opts;
         char *p;
-        char *context = NULL, *defcontext = NULL;
-        char *fscontext = NULL, *rootcontext = NULL;
-        int rc, num_mnt_opts = 0;
-        struct security_mnt_opts *opts = *mnt_opts;
-
-        if (!opts) {
-                opts = kzalloc(sizeof(struct security_mnt_opts), GFP_KERNEL);
-                *mnt_opts = opts;
-                if (!opts)
-                        return -ENOMEM;
-        }
-
-        opts->num_mnt_opts = 0;
+        int rc;
 
         /* Standard string-based options. */
         while ((p = strsep(&options, "|")) != NULL) {
@@ -1023,54 +1001,60 @@ static int selinux_parse_opts_str(char *options,
 
                 token = match_token(p, tokens, args);
 
+                if (!opts) {
+                        opts = kzalloc(sizeof(struct selinux_mnt_opts), GFP_KERNEL);
+                        if (!opts)
+                                return -ENOMEM;
+                }
+
                 switch (token) {
                 case Opt_context:
-                        if (context || defcontext) {
+                        if (opts->context || opts->defcontext) {
                                 rc = -EINVAL;
                                 pr_warn(SEL_MOUNT_FAIL_MSG);
                                 goto out_err;
                         }
-                        context = match_strdup(&args[0]);
-                        if (!context) {
+                        opts->context = match_strdup(&args[0]);
+                        if (!opts->context) {
                                 rc = -ENOMEM;
                                 goto out_err;
                         }
                         break;
 
                 case Opt_fscontext:
-                        if (fscontext) {
+                        if (opts->fscontext) {
                                 rc = -EINVAL;
                                 pr_warn(SEL_MOUNT_FAIL_MSG);
                                 goto out_err;
                         }
-                        fscontext = match_strdup(&args[0]);
-                        if (!fscontext) {
+                        opts->fscontext = match_strdup(&args[0]);
+                        if (!opts->fscontext) {
                                 rc = -ENOMEM;
                                 goto out_err;
                         }
                         break;
 
                 case Opt_rootcontext:
-                        if (rootcontext) {
+                        if (opts->rootcontext) {
                                 rc = -EINVAL;
                                 pr_warn(SEL_MOUNT_FAIL_MSG);
                                 goto out_err;
                         }
-                        rootcontext = match_strdup(&args[0]);
-                        if (!rootcontext) {
+                        opts->rootcontext = match_strdup(&args[0]);
+                        if (!opts->rootcontext) {
                                 rc = -ENOMEM;
                                 goto out_err;
                         }
                         break;
 
                 case Opt_defcontext:
-                        if (context || defcontext) {
+                        if (opts->context || opts->defcontext) {
                                 rc = -EINVAL;
                                 pr_warn(SEL_MOUNT_FAIL_MSG);
                                 goto out_err;
                         }
-                        defcontext = match_strdup(&args[0]);
-                        if (!defcontext) {
+                        opts->defcontext = match_strdup(&args[0]);
+                        if (!opts->defcontext) {
                                 rc = -ENOMEM;
                                 goto out_err;
                         }
@@ -1084,43 +1068,12 @@ static int selinux_parse_opts_str(char *options,
 
                 }
         }
-
-        rc = -ENOMEM;
-        opts->mnt_opts = kcalloc(NUM_SEL_MNT_OPTS, sizeof(char *), GFP_KERNEL);
-        if (!opts->mnt_opts)
-                goto out_err;
-
-        opts->mnt_opts_flags = kcalloc(NUM_SEL_MNT_OPTS, sizeof(int),
-                                       GFP_KERNEL);
-        if (!opts->mnt_opts_flags)
-                goto out_err;
-
-        if (fscontext) {
-                opts->mnt_opts[num_mnt_opts] = fscontext;
-                opts->mnt_opts_flags[num_mnt_opts++] = FSCONTEXT_MNT;
-        }
-        if (context) {
-                opts->mnt_opts[num_mnt_opts] = context;
-                opts->mnt_opts_flags[num_mnt_opts++] = CONTEXT_MNT;
-        }
-        if (rootcontext) {
-                opts->mnt_opts[num_mnt_opts] = rootcontext;
-                opts->mnt_opts_flags[num_mnt_opts++] = ROOTCONTEXT_MNT;
-        }
-        if (defcontext) {
-                opts->mnt_opts[num_mnt_opts] = defcontext;
-                opts->mnt_opts_flags[num_mnt_opts++] = DEFCONTEXT_MNT;
-        }
-
-        opts->num_mnt_opts = num_mnt_opts;
+        *mnt_opts = opts;
         return 0;
 
 out_err:
-        security_free_mnt_opts(mnt_opts);
-        kfree(context);
-        kfree(defcontext);
-        kfree(fscontext);
-        kfree(rootcontext);
+        if (opts)
+                selinux_free_mnt_opts(opts);
         return rc;
 }
 
@@ -2752,10 +2705,10 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
 
 static int selinux_sb_remount(struct super_block *sb, void *mnt_opts)
 {
-        struct security_mnt_opts *opts = mnt_opts;
-        int i, *flags;
-        char **mount_options;
+        struct selinux_mnt_opts *opts = mnt_opts;
         struct superblock_security_struct *sbsec = sb->s_security;
+        u32 sid;
+        int rc;
 
         if (!(sbsec->flags & SE_SBINITIALIZED))
                 return 0;
@@ -2763,48 +2716,35 @@ static int selinux_sb_remount(struct super_block *sb, void *mnt_opts)
         if (!opts)
                 return 0;
 
-        mount_options = opts->mnt_opts;
-        flags = opts->mnt_opts_flags;
-
-        for (i = 0; i < opts->num_mnt_opts; i++) {
-                u32 sid;
-                int rc;
-
-                if (flags[i] == SBLABEL_MNT)
-                        continue;
-                rc = security_context_str_to_sid(&selinux_state,
-                                                 mount_options[i], &sid,
-                                                 GFP_KERNEL);
-                if (rc) {
-                        pr_warn("SELinux: security_context_str_to_sid"
-                               "(%s) failed for (dev %s, type %s) errno=%d\n",
-                               mount_options[i], sb->s_id, sb->s_type->name, rc);
+        if (opts->fscontext) {
+                rc = parse_sid(sb, opts->fscontext, &sid);
+                if (rc)
                         return rc;
-                }
-                switch (flags[i]) {
-                case FSCONTEXT_MNT:
-                        if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, sid))
-                                goto out_bad_option;
-                        break;
-                case CONTEXT_MNT:
-                        if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, sid))
-                                goto out_bad_option;
-                        break;
-                case ROOTCONTEXT_MNT: {
-                        struct inode_security_struct *root_isec;
-                        root_isec = backing_inode_security(sb->s_root);
-
-                        if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, sid))
-                                goto out_bad_option;
-                        break;
-                }
-                case DEFCONTEXT_MNT:
-                        if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, sid))
-                                goto out_bad_option;
-                        break;
-                default:
-                        return -EINVAL;
-                }
+                if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, sid))
+                        goto out_bad_option;
+        }
+        if (opts->context) {
+                rc = parse_sid(sb, opts->context, &sid);
+                if (rc)
+                        return rc;
+                if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, sid))
+                        goto out_bad_option;
+        }
+        if (opts->rootcontext) {
+                struct inode_security_struct *root_isec;
+                root_isec = backing_inode_security(sb->s_root);
+                rc = parse_sid(sb, opts->rootcontext, &sid);
+                if (rc)
+                        return rc;
+                if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, sid))
+                        goto out_bad_option;
+        }
+        if (opts->defcontext) {
+                rc = parse_sid(sb, opts->defcontext, &sid);
+                if (rc)
+                        return rc;
+                if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, sid))
+                        goto out_bad_option;
         }
         return 0;