LSM/SELinux: show LSM mount options in /proc/mounts

This patch causes SELinux mount options to show up in /proc/mounts.  As
with other code in the area seq_put errors are ignored.  Other LSM's
will not have their mount options displayed until they fill in their own
security_sb_show_options() function.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: James Morris <jmorris@namei.org>

diff --git a/fs/namespace.c b/fs/namespace.c
index 4fc302c2a0e0f886e4026288bcdc50888ddf3551..4f6f7635b59c93c0c2a86a8deff1f59c567de9f5 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -750,7 +750,7 @@ struct proc_fs_info {
        const char *str;
 };
 
-static void show_sb_opts(struct seq_file *m, struct super_block *sb)
+static int show_sb_opts(struct seq_file *m, struct super_block *sb)
 {
        static const struct proc_fs_info fs_info[] = {
                { MS_SYNCHRONOUS, ",sync" },
@@ -764,6 +764,8 @@ static void show_sb_opts(struct seq_file *m, struct super_block *sb)
                if (sb->s_flags & fs_infop->flag)
                        seq_puts(m, fs_infop->str);
        }
+
+       return security_sb_show_options(m, sb);
 }
 
 static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
@@ -806,11 +808,14 @@ static int show_vfsmnt(struct seq_file *m, void *v)
        seq_putc(m, ' ');
        show_type(m, mnt->mnt_sb);
        seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
-       show_sb_opts(m, mnt->mnt_sb);
+       err = show_sb_opts(m, mnt->mnt_sb);
+       if (err)
+               goto out;
        show_mnt_opts(m, mnt);
        if (mnt->mnt_sb->s_op->show_options)
                err = mnt->mnt_sb->s_op->show_options(m, mnt);
        seq_puts(m, " 0 0\n");
+out:
        return err;
 }
 
@@ -865,10 +870,13 @@ static int show_mountinfo(struct seq_file *m, void *v)
        seq_putc(m, ' ');
        mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
        seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");
-       show_sb_opts(m, sb);
+       err = show_sb_opts(m, sb);
+       if (err)
+               goto out;
        if (sb->s_op->show_options)
                err = sb->s_op->show_options(m, mnt);
        seq_putc(m, '\n');
+out:
        return err;
 }
 

diff --git a/include/linux/security.h b/include/linux/security.h
index 62bd80cb7f876d326cf79760554627ae0a7d42bc..c8ad8ec684b4ccac7eb429e8e1f08d55759b01a9 100644 (file)
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -80,6 +80,7 @@ struct xfrm_selector;
 struct xfrm_policy;
 struct xfrm_state;
 struct xfrm_user_sec_ctx;
+struct seq_file;
 
 extern int cap_netlink_send(struct sock *sk, struct sk_buff *skb);
 extern int cap_netlink_recv(struct sk_buff *skb, int cap);
@@ -1331,6 +1332,7 @@ struct security_operations {
        void (*sb_free_security) (struct super_block *sb);
        int (*sb_copy_data) (char *orig, char *copy);
        int (*sb_kern_mount) (struct super_block *sb, void *data);
+       int (*sb_show_options) (struct seq_file *m, struct super_block *sb);
        int (*sb_statfs) (struct dentry *dentry);
        int (*sb_mount) (char *dev_name, struct path *path,
                         char *type, unsigned long flags, void *data);
@@ -1610,6 +1612,7 @@ 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_kern_mount(struct super_block *sb, void *data);
+int security_sb_show_options(struct seq_file *m, struct super_block *sb);
 int security_sb_statfs(struct dentry *dentry);
 int security_sb_mount(char *dev_name, struct path *path,
                      char *type, unsigned long flags, void *data);
@@ -1887,6 +1890,12 @@ static inline int security_sb_kern_mount(struct super_block *sb, void *data)
        return 0;
 }
 
+static inline int security_sb_show_options(struct seq_file *m,
+                                          struct super_block *sb)
+{
+       return 0;
+}
+
 static inline int security_sb_statfs(struct dentry *dentry)
 {
        return 0;

diff --git a/security/dummy.c b/security/dummy.c
index 1db712d99dc7e969380589e4659e8f54bcfbf89a..c155f08e9dd8643ee84dec4bbb92e10d1652a1ea 100644 (file)
--- a/security/dummy.c
+++ b/security/dummy.c
@@ -194,6 +194,11 @@ static int dummy_sb_kern_mount (struct super_block *sb, void *data)
        return 0;
 }
 
+static int dummy_sb_show_options(struct seq_file *m, struct super_block *sb)
+{
+       return 0;
+}
+
 static int dummy_sb_statfs (struct dentry *dentry)
 {
        return 0;
@@ -1088,6 +1093,7 @@ void security_fixup_ops (struct security_operations *ops)
        set_to_dummy_if_null(ops, sb_free_security);
        set_to_dummy_if_null(ops, sb_copy_data);
        set_to_dummy_if_null(ops, sb_kern_mount);
+       set_to_dummy_if_null(ops, sb_show_options);
        set_to_dummy_if_null(ops, sb_statfs);
        set_to_dummy_if_null(ops, sb_mount);
        set_to_dummy_if_null(ops, sb_check_sb);

diff --git a/security/security.c b/security/security.c
index 2c0a5876b939ef0e036f487ca199448fb13afea4..de74fdccde261782ba4c759b4f93398a400d58de 100644 (file)
--- a/security/security.c
+++ b/security/security.c
@@ -292,6 +292,11 @@ int security_sb_kern_mount(struct super_block *sb, void *data)
        return security_ops->sb_kern_mount(sb, data);
 }
 
+int security_sb_show_options(struct seq_file *m, struct super_block *sb)
+{
+       return security_ops->sb_show_options(m, sb);
+}
+
 int security_sb_statfs(struct dentry *dentry)
 {
        return security_ops->sb_statfs(dentry);

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 85f74f665765e33006cd0996fab42be5a457acdb..33dee83fdd2f43ce5b59580b5e9b3e80d3bb5d9d 100644 (file)
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -9,7 +9,8 @@
  *           James Morris <jmorris@redhat.com>
  *
  *  Copyright (C) 2001,2002 Networks Associates Technology, Inc.
- *  Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
+ *  Copyright (C) 2003-2008 Red Hat, Inc., James Morris <jmorris@redhat.com>
+ *                                        Eric Paris <eparis@redhat.com>
  *  Copyright (C) 2004-2005 Trusted Computer Solutions, Inc.
  *                         <dgoeddel@trustedcs.com>
  *  Copyright (C) 2006, 2007 Hewlett-Packard Development Company, L.P.
@@ -970,6 +971,57 @@ out_err:
        return rc;
 }
 
+void selinux_write_opts(struct seq_file *m, struct security_mnt_opts *opts)
+{
+       int i;
+       char *prefix;
+
+       for (i = 0; i < opts->num_mnt_opts; i++) {
+               char *has_comma = strchr(opts->mnt_opts[i], ',');
+
+               switch (opts->mnt_opts_flags[i]) {
+               case CONTEXT_MNT:
+                       prefix = CONTEXT_STR;
+                       break;
+               case FSCONTEXT_MNT:
+                       prefix = FSCONTEXT_STR;
+                       break;
+               case ROOTCONTEXT_MNT:
+                       prefix = ROOTCONTEXT_STR;
+                       break;
+               case DEFCONTEXT_MNT:
+                       prefix = DEFCONTEXT_STR;
+                       break;
+               default:
+                       BUG();
+               };
+               /* we need a comma before each option */
+               seq_putc(m, ',');
+               seq_puts(m, prefix);
+               if (has_comma)
+                       seq_putc(m, '\"');
+               seq_puts(m, opts->mnt_opts[i]);
+               if (has_comma)
+                       seq_putc(m, '\"');
+       }
+}
+
+static int selinux_sb_show_options(struct seq_file *m, struct super_block *sb)
+{
+       struct security_mnt_opts opts;
+       int rc;
+
+       rc = selinux_get_mnt_opts(sb, &opts);
+       if (rc)
+               return rc;
+
+       selinux_write_opts(m, &opts);
+
+       security_free_mnt_opts(&opts);
+
+       return rc;
+}
+
 static inline u16 inode_mode_to_security_class(umode_t mode)
 {
        switch (mode & S_IFMT) {
@@ -5365,6 +5417,7 @@ static struct security_operations selinux_ops = {
        .sb_free_security =             selinux_sb_free_security,
        .sb_copy_data =                 selinux_sb_copy_data,
        .sb_kern_mount =                selinux_sb_kern_mount,
+       .sb_show_options =              selinux_sb_show_options,
        .sb_statfs =                    selinux_sb_statfs,
        .sb_mount =                     selinux_mount,
        .sb_umount =                    selinux_umount,