LSM: lift parsing LSM options into the caller of ->sb_kern_mount()

This paves the way for retaining the LSM options from a common filesystem
mount context during a mount parameter parsing phase to be instituted prior
to actual mount/reconfiguration actions.

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

diff --git a/fs/super.c b/fs/super.c
index 6654de03589399924caf6109f513424be7ae24f2..8d9c9199832d7ecd9c74cbba96364980c0b7f6b6 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -1246,17 +1246,26 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
 {
        struct dentry *root;
        struct super_block *sb;
-       char *secdata = NULL;
        int error = -ENOMEM;
+       struct security_mnt_opts opts;
+
+       security_init_mnt_opts(&opts);
 
        if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
-               secdata = alloc_secdata();
+               char *secdata = alloc_secdata();
                if (!secdata)
-                       goto out;
+                       return ERR_PTR(-ENOMEM);
 
                error = security_sb_copy_data(data, secdata);
+               if (error) {
+                       free_secdata(secdata);
+                       return ERR_PTR(error);
+               }
+
+               error = security_sb_parse_opts_str(secdata, &opts);
+               free_secdata(secdata);
                if (error)
-                       goto out_free_secdata;
+                       return ERR_PTR(error);
        }
 
        root = type->mount(type, flags, name, data);
@@ -1277,7 +1286,7 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
        smp_wmb();
        sb->s_flags |= SB_BORN;
 
-       error = security_sb_kern_mount(sb, flags, secdata);
+       error = security_sb_kern_mount(sb, flags, &opts);
        if (error)
                goto out_sb;
 
@@ -1291,14 +1300,13 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
                "negative value (%lld)\n", type->name, sb->s_maxbytes);
 
        up_write(&sb->s_umount);
-       free_secdata(secdata);
+       security_free_mnt_opts(&opts);
        return root;
 out_sb:
        dput(root);
        deactivate_locked_super(sb);
 out_free_secdata:
-       free_secdata(secdata);
-out:
+       security_free_mnt_opts(&opts);
        return ERR_PTR(error);
 }
 

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index aaeb7fa24dc48c0f599da905a48595c7607eeefd..c7f67341fd1dbb9054e1da74bf21a8cc25f36ca6 100644 (file)
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1463,7 +1463,8 @@ union security_list_options {
        void (*sb_free_security)(struct super_block *sb);
        int (*sb_copy_data)(char *orig, char *copy);
        int (*sb_remount)(struct super_block *sb, void *data);
-       int (*sb_kern_mount)(struct super_block *sb, int flags, void *data);
+       int (*sb_kern_mount)(struct super_block *sb, int flags,
+                            struct security_mnt_opts *opts);
        int (*sb_show_options)(struct seq_file *m, struct super_block *sb);
        int (*sb_statfs)(struct dentry *dentry);
        int (*sb_mount)(const char *dev_name, const struct path *path,

diff --git a/include/linux/security.h b/include/linux/security.h
index d170a5b031f3801021799816f203821d65fc6235..f2f88e41f35f9d1c863f9f58f4d56f0928198c74 100644 (file)
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -250,7 +250,8 @@ int security_sb_alloc(struct super_block *sb);
 void security_sb_free(struct super_block *sb);
 int security_sb_copy_data(char *orig, char *copy);
 int security_sb_remount(struct super_block *sb, void *data);
-int security_sb_kern_mount(struct super_block *sb, int flags, void *data);
+int security_sb_kern_mount(struct super_block *sb, int flags,
+                          struct security_mnt_opts *opts);
 int security_sb_show_options(struct seq_file *m, struct super_block *sb);
 int security_sb_statfs(struct dentry *dentry);
 int security_sb_mount(const char *dev_name, const struct path *path,
@@ -565,7 +566,8 @@ static inline int security_sb_remount(struct super_block *sb, void *data)
        return 0;
 }
 
-static inline int security_sb_kern_mount(struct super_block *sb, int flags, void *data)
+static inline int security_sb_kern_mount(struct super_block *sb, int flags,
+                                        struct security_mnt_opts *opts)
 {
        return 0;
 }

diff --git a/security/security.c b/security/security.c
index 04d173eb93f6e6a493466d92a2f66e6b9790a94a..b5fc8e1e849c643f79e08d504fbd248b8c57db10 100644 (file)
--- a/security/security.c
+++ b/security/security.c
@@ -395,9 +395,10 @@ int security_sb_remount(struct super_block *sb, void *data)
        return call_int_hook(sb_remount, 0, sb, data);
 }
 
-int security_sb_kern_mount(struct super_block *sb, int flags, void *data)
+int security_sb_kern_mount(struct super_block *sb, int flags,
+                          struct security_mnt_opts *opts)
 {
-       return call_int_hook(sb_kern_mount, 0, sb, flags, data);
+       return call_int_hook(sb_kern_mount, 0, sb, flags, opts);
 }
 
 int security_sb_show_options(struct seq_file *m, struct super_block *sb)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 4bd6f9435e2f1705a649d581f9ba546157c1a925..ba229d4a64d396c486dcad982be538aabe048d69 100644 (file)
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2897,30 +2897,12 @@ out_bad_option:
        goto out_free_opts;
 }
 
-static int selinux_sb_kern_mount(struct super_block *sb, int flags, void *data)
+static int selinux_sb_kern_mount(struct super_block *sb, int flags,
+                                struct security_mnt_opts *opts)
 {
-       char *options = data;
        const struct cred *cred = current_cred();
        struct common_audit_data ad;
-       int rc = 0;
-       struct security_mnt_opts opts;
-
-       security_init_mnt_opts(&opts);
-
-       if (!data)
-               goto out;
-
-       BUG_ON(sb->s_type->fs_flags & FS_BINARY_MOUNTDATA);
-
-       rc = selinux_parse_opts_str(options, &opts);
-       if (rc)
-               goto out_err;
-
-out:
-       rc = selinux_set_mnt_opts(sb, &opts, 0, NULL);
-
-out_err:
-       security_free_mnt_opts(&opts);
+       int rc = selinux_set_mnt_opts(sb, opts, 0, NULL);
        if (rc)
                return rc;
 

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 73e41797960e3236a55f7aaf431e866f39e4bea3..1d465ae3d11cd423bccda0f6bf826c0903c1b436 100644 (file)
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -859,27 +859,10 @@ static int smack_set_mnt_opts(struct super_block *sb,
  *
  * Returns 0 on success, an error code on failure
  */
-static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
+static int smack_sb_kern_mount(struct super_block *sb, int flags,
+                              struct security_mnt_opts *opts)
 {
-       int rc = 0;
-       char *options = data;
-       struct security_mnt_opts opts;
-
-       security_init_mnt_opts(&opts);
-
-       if (!options)
-               goto out;
-
-       rc = smack_parse_opts_str(options, &opts);
-       if (rc)
-               goto out_err;
-
-out:
-       rc = smack_set_mnt_opts(sb, &opts, 0, NULL);
-
-out_err:
-       security_free_mnt_opts(&opts);
-       return rc;
+       return smack_set_mnt_opts(sb, opts, 0, NULL);
 }
 
 /**