Merge master.kernel.org:/home/rmk/linux-2.6-serial

[pandora-kernel.git] / security / selinux / hooks.c

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 24caaee..2e8b4df 100644 (file)
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -246,6 +246,7 @@ static int superblock_alloc_security(struct super_block *sb)
        sbsec->sb = sb;
        sbsec->sid = SECINITSID_UNLABELED;
        sbsec->def_sid = SECINITSID_FILE;
+       sbsec->mntpoint_sid = SECINITSID_UNLABELED;
        sb->s_security = sbsec;
 
        return 0;
@@ -319,19 +320,53 @@ enum {
        Opt_context = 1,
        Opt_fscontext = 2,
        Opt_defcontext = 4,
+       Opt_rootcontext = 8,
 };
 
 static match_table_t tokens = {
        {Opt_context, "context=%s"},
        {Opt_fscontext, "fscontext=%s"},
        {Opt_defcontext, "defcontext=%s"},
+       {Opt_rootcontext, "rootcontext=%s"},
 };
 
 #define SEL_MOUNT_FAIL_MSG "SELinux:  duplicate or incompatible mount options\n"
 
+static int may_context_mount_sb_relabel(u32 sid,
+                       struct superblock_security_struct *sbsec,
+                       struct task_security_struct *tsec)
+{
+       int rc;
+
+       rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
+                         FILESYSTEM__RELABELFROM, NULL);
+       if (rc)
+               return rc;
+
+       rc = avc_has_perm(tsec->sid, sid, SECCLASS_FILESYSTEM,
+                         FILESYSTEM__RELABELTO, NULL);
+       return rc;
+}
+
+static int may_context_mount_inode_relabel(u32 sid,
+                       struct superblock_security_struct *sbsec,
+                       struct task_security_struct *tsec)
+{
+       int rc;
+       rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
+                         FILESYSTEM__RELABELFROM, NULL);
+       if (rc)
+               return rc;
+
+       rc = avc_has_perm(sid, sbsec->sid, SECCLASS_FILESYSTEM,
+                         FILESYSTEM__ASSOCIATE, NULL);
+       return rc;
+}
+
 static int try_context_mount(struct super_block *sb, void *data)
 {
        char *context = NULL, *defcontext = NULL;
+       char *fscontext = NULL, *rootcontext = NULL;
        const char *name;
        u32 sid;
        int alloc = 0, rc = 0, seen = 0;
@@ -374,7 +409,7 @@ static int try_context_mount(struct super_block *sb, void *data)
 
                        switch (token) {
                        case Opt_context:
-                               if (seen) {
+                               if (seen & (Opt_context|Opt_defcontext)) {
                                        rc = -EINVAL;
                                        printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
                                        goto out_free;
@@ -390,13 +425,13 @@ static int try_context_mount(struct super_block *sb, void *data)
                                break;
 
                        case Opt_fscontext:
-                               if (seen & (Opt_context|Opt_fscontext)) {
+                               if (seen & Opt_fscontext) {
                                        rc = -EINVAL;
                                        printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
                                        goto out_free;
                                }
-                               context = match_strdup(&args[0]);
-                               if (!context) {
+                               fscontext = match_strdup(&args[0]);
+                               if (!fscontext) {
                                        rc = -ENOMEM;
                                        goto out_free;
                                }
@@ -405,6 +440,22 @@ static int try_context_mount(struct super_block *sb, void *data)
                                seen |= Opt_fscontext;
                                break;
 
+                       case Opt_rootcontext:
+                               if (seen & Opt_rootcontext) {
+                                       rc = -EINVAL;
+                                       printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
+                                       goto out_free;
+                               }
+                               rootcontext = match_strdup(&args[0]);
+                               if (!rootcontext) {
+                                       rc = -ENOMEM;
+                                       goto out_free;
+                               }
+                               if (!alloc)
+                                       alloc = 1;
+                               seen |= Opt_rootcontext;
+                               break;
+
                        case Opt_defcontext:
                                if (sbsec->behavior != SECURITY_FS_USE_XATTR) {
                                        rc = -EINVAL;
@@ -441,6 +492,28 @@ static int try_context_mount(struct super_block *sb, void *data)
        if (!seen)
                goto out;
 
+       /* sets the context of the superblock for the fs being mounted. */
+       if (fscontext) {
+               rc = security_context_to_sid(fscontext, strlen(fscontext), &sid);
+               if (rc) {
+                       printk(KERN_WARNING "SELinux: security_context_to_sid"
+                              "(%s) failed for (dev %s, type %s) errno=%d\n",
+                              fscontext, sb->s_id, name, rc);
+                       goto out_free;
+               }
+
+               rc = may_context_mount_sb_relabel(sid, sbsec, tsec);
+               if (rc)
+                       goto out_free;
+
+               sbsec->sid = sid;
+       }
+
+       /*
+        * Switch to using mount point labeling behavior.
+        * sets the label used on all file below the mountpoint, and will set
+        * the superblock context if not already set.
+        */
        if (context) {
                rc = security_context_to_sid(context, strlen(context), &sid);
                if (rc) {
@@ -450,20 +523,34 @@ static int try_context_mount(struct super_block *sb, void *data)
                        goto out_free;
                }
 
-               rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
-                                 FILESYSTEM__RELABELFROM, NULL);
+               rc = may_context_mount_sb_relabel(sid, sbsec, tsec);
                if (rc)
                        goto out_free;
 
-               rc = avc_has_perm(tsec->sid, sid, SECCLASS_FILESYSTEM,
-                                 FILESYSTEM__RELABELTO, NULL);
-               if (rc)
+               if (!fscontext)
+                       sbsec->sid = sid;
+               sbsec->mntpoint_sid = sid;
+
+               sbsec->behavior = SECURITY_FS_USE_MNTPOINT;
+       }
+
+       if (rootcontext) {
+               struct inode *inode = sb->s_root->d_inode;
+               struct inode_security_struct *isec = inode->i_security;
+               rc = security_context_to_sid(rootcontext, strlen(rootcontext), &sid);
+               if (rc) {
+                       printk(KERN_WARNING "SELinux: security_context_to_sid"
+                              "(%s) failed for (dev %s, type %s) errno=%d\n",
+                              rootcontext, sb->s_id, name, rc);
                        goto out_free;
+               }
 
-               sbsec->sid = sid;
+               rc = may_context_mount_inode_relabel(sid, sbsec, tsec);
+               if (rc)
+                       goto out_free;
 
-               if (seen & Opt_context)
-                       sbsec->behavior = SECURITY_FS_USE_MNTPOINT;
+               isec->sid = sid;
+               isec->initialized = 1;
        }
 
        if (defcontext) {
@@ -478,13 +565,7 @@ static int try_context_mount(struct super_block *sb, void *data)
                if (sid == sbsec->def_sid)
                        goto out_free;
 
-               rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
-                                 FILESYSTEM__RELABELFROM, NULL);
-               if (rc)
-                       goto out_free;
-
-               rc = avc_has_perm(sid, sbsec->sid, SECCLASS_FILESYSTEM,
-                                 FILESYSTEM__ASSOCIATE, NULL);
+               rc = may_context_mount_inode_relabel(sid, sbsec, tsec);
                if (rc)
                        goto out_free;
 
@@ -495,6 +576,8 @@ out_free:
        if (alloc) {
                kfree(context);
                kfree(defcontext);
+               kfree(fscontext);
+               kfree(rootcontext);
        }
 out:
        return rc;
@@ -876,8 +959,11 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
                        goto out;
                isec->sid = sid;
                break;
+       case SECURITY_FS_USE_MNTPOINT:
+               isec->sid = sbsec->mntpoint_sid;
+               break;
        default:
-               /* Default to the fs SID. */
+               /* Default to the fs superblock SID. */
                isec->sid = sbsec->sid;
 
                if (sbsec->proc) {
@@ -1843,7 +1929,8 @@ static inline int selinux_option(char *option, int len)
 {
        return (match_prefix("context=", sizeof("context=")-1, option, len) ||
                match_prefix("fscontext=", sizeof("fscontext=")-1, option, len) ||
-               match_prefix("defcontext=", sizeof("defcontext=")-1, option, len));
+               match_prefix("defcontext=", sizeof("defcontext=")-1, option, len) ||
+               match_prefix("rootcontext=", sizeof("rootcontext=")-1, option, len));
 }
 
 static inline void take_option(char **to, char *from, int *first, int len)