LSM: separate LSM_AUDIT_DATA_DENTRY from LSM_AUDIT_DATA_PATH

This patch separates and audit message that only contains a dentry from
one that contains a full path.  This allows us to make it harder to
misuse the interfaces or for the interfaces to be implemented wrong.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>

5 files changed, 52 insertions, 42 deletions

diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h
index bbaceab83a65..88e78dedc2e8 100644
--- a/include/linux/lsm_audit.h
+++ b/include/linux/lsm_audit.h
@@ -36,9 +36,11 @@ struct common_audit_data {
 #define LSM_AUDIT_DATA_NONE     7
 #define LSM_AUDIT_DATA_KMOD     8
 #define LSM_AUDIT_DATA_INODE    9
+#define LSM_AUDIT_DATA_DENTRY   10
         struct task_struct *tsk;
         union   {
                 struct path path;
+                struct dentry *dentry;
                 struct inode *inode;
                 struct {
                         int netif;
diff --git a/security/lsm_audit.c b/security/lsm_audit.c
index 2e846052cbf4..893af8a2fa1e 100644
--- a/security/lsm_audit.c
+++ b/security/lsm_audit.c
@@ -229,17 +229,24 @@ static void dump_common_audit_data(struct audit_buffer *ab,
                 audit_log_format(ab, " capability=%d ", a->u.cap);
                 break;
         case LSM_AUDIT_DATA_PATH: {
-                struct dentry *dentry = a->u.path.dentry;
                 struct inode *inode;
 
-                if (a->u.path.mnt) {
-                        audit_log_d_path(ab, "path=", &a->u.path);
-                } else {
-                        audit_log_format(ab, " name=");
-                        audit_log_untrustedstring(ab,
-                                         dentry->d_name.name);
-                }
-                inode = dentry->d_inode;
+                audit_log_d_path(ab, "path=", &a->u.path);
+
+                inode = a->u.path.dentry->d_inode;
+                if (inode)
+                        audit_log_format(ab, " dev=%s ino=%lu",
+                                        inode->i_sb->s_id,
+                                        inode->i_ino);
+                break;
+        }
+        case LSM_AUDIT_DATA_DENTRY: {
+                struct inode *inode;
+
+                audit_log_format(ab, " name=");
+                audit_log_untrustedstring(ab, a->u.dentry->d_name.name);
+
+                inode = a->u.dentry->d_inode;
                 if (inode)
                         audit_log_format(ab, " dev=%s ino=%lu",
                                         inode->i_sb->s_id,
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index ad664d3056eb..9e8078a42a94 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1569,8 +1569,8 @@ static int may_create(struct inode *dir,
         sid = tsec->sid;
         newsid = tsec->create_sid;
 
-        COMMON_AUDIT_DATA_INIT(&ad, PATH);
-        ad.u.path.dentry = dentry;
+        COMMON_AUDIT_DATA_INIT(&ad, DENTRY);
+        ad.u.dentry = dentry;
 
         rc = avc_has_perm(sid, dsec->sid, SECCLASS_DIR,
                           DIR__ADD_NAME | DIR__SEARCH,
@@ -1621,8 +1621,8 @@ static int may_link(struct inode *dir,
         dsec = dir->i_security;
         isec = dentry->d_inode->i_security;
 
-        COMMON_AUDIT_DATA_INIT(&ad, PATH);
-        ad.u.path.dentry = dentry;
+        COMMON_AUDIT_DATA_INIT(&ad, DENTRY);
+        ad.u.dentry = dentry;
 
         av = DIR__SEARCH;
         av |= (kind ? DIR__REMOVE_NAME : DIR__ADD_NAME);
@@ -1667,9 +1667,9 @@ static inline int may_rename(struct inode *old_dir,
         old_is_dir = S_ISDIR(old_dentry->d_inode->i_mode);
         new_dsec = new_dir->i_security;
 
-        COMMON_AUDIT_DATA_INIT(&ad, PATH);
+        COMMON_AUDIT_DATA_INIT(&ad, DENTRY);
 
-        ad.u.path.dentry = old_dentry;
+        ad.u.dentry = old_dentry;
         rc = avc_has_perm(sid, old_dsec->sid, SECCLASS_DIR,
                           DIR__REMOVE_NAME | DIR__SEARCH, &ad);
         if (rc)
@@ -1685,7 +1685,7 @@ static inline int may_rename(struct inode *old_dir,
                         return rc;
         }
 
-        ad.u.path.dentry = new_dentry;
+        ad.u.dentry = new_dentry;
         av = DIR__ADD_NAME | DIR__SEARCH;
         if (new_dentry->d_inode)
                 av |= DIR__REMOVE_NAME;
@@ -2468,8 +2468,8 @@ static int selinux_sb_kern_mount(struct super_block *sb, int flags, void *data)
         if (flags & MS_KERNMOUNT)
                 return 0;
 
-        COMMON_AUDIT_DATA_INIT(&ad, PATH);
-        ad.u.path.dentry = sb->s_root;
+        COMMON_AUDIT_DATA_INIT(&ad, DENTRY);
+        ad.u.dentry = sb->s_root;
         return superblock_has_perm(cred, sb, FILESYSTEM__MOUNT, &ad);
 }
 
@@ -2478,8 +2478,8 @@ static int selinux_sb_statfs(struct dentry *dentry)
         const struct cred *cred = current_cred();
         struct common_audit_data ad;
 
-        COMMON_AUDIT_DATA_INIT(&ad, PATH);
-        ad.u.path.dentry = dentry->d_sb->s_root;
+        COMMON_AUDIT_DATA_INIT(&ad, DENTRY);
+        ad.u.dentry = dentry->d_sb->s_root;
         return superblock_has_perm(cred, dentry->d_sb, FILESYSTEM__GETATTR, &ad);
 }
 
@@ -2732,8 +2732,8 @@ static int selinux_inode_setxattr(struct dentry *dentry, const char *name,
         if (!is_owner_or_cap(inode))
                 return -EPERM;
 
-        COMMON_AUDIT_DATA_INIT(&ad, PATH);
-        ad.u.path.dentry = dentry;
+        COMMON_AUDIT_DATA_INIT(&ad, DENTRY);
+        ad.u.dentry = dentry;
 
         rc = avc_has_perm(sid, isec->sid, isec->sclass,
                           FILE__RELABELFROM, &ad);
diff --git a/security/smack/smack.h b/security/smack/smack.h
index a16925c0e91a..2b6c6a516123 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -316,12 +316,7 @@ static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
                                                     struct dentry *d)
 {
-        a->a.u.path.dentry = d;
-}
-static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
-                                                 struct vfsmount *m)
-{
-        a->a.u.path.mnt = m;
+        a->a.u.dentry = d;
 }
 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
                                               struct inode *i)
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index eeb393fbf925..a3bdd1383928 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -383,7 +383,7 @@ static int smack_sb_statfs(struct dentry *dentry)
         int rc;
         struct smk_audit_info ad;
 
-        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
+        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
         smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
         rc = smk_curacc(sbp->smk_floor, MAY_READ, &ad);
@@ -425,10 +425,13 @@ static int smack_sb_umount(struct vfsmount *mnt, int flags)
 {
         struct superblock_smack *sbp;
         struct smk_audit_info ad;
+        struct path path;
+
+        path.dentry = mnt->mnt_root;
+        path.mnt = mnt;
 
         smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
-        smk_ad_setfield_u_fs_path_dentry(&ad, mnt->mnt_root);
-        smk_ad_setfield_u_fs_path_mnt(&ad, mnt);
+        smk_ad_setfield_u_fs_path(&ad, path);
 
         sbp = mnt->mnt_sb->s_security;
         return smk_curacc(sbp->smk_floor, MAY_WRITE, &ad);
@@ -563,7 +566,7 @@ static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
         struct smk_audit_info ad;
         int rc;
 
-        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
+        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
         smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);
 
         isp = smk_of_inode(old_dentry->d_inode);
@@ -592,7 +595,7 @@ static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
         struct smk_audit_info ad;
         int rc;
 
-        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
+        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
         smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
         /*
@@ -623,7 +626,7 @@ static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
         struct smk_audit_info ad;
         int rc;
 
-        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
+        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
         smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
         /*
@@ -663,7 +666,7 @@ static int smack_inode_rename(struct inode *old_inode,
         char *isp;
         struct smk_audit_info ad;
 
-        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
+        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
         smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);
 
         isp = smk_of_inode(old_dentry->d_inode);
@@ -720,7 +723,7 @@ static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
          */
         if (iattr->ia_valid & ATTR_FORCE)
                 return 0;
-        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
+        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
         smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
         return smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
@@ -736,10 +739,13 @@ static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
 static int smack_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
 {
         struct smk_audit_info ad;
+        struct path path;
+
+        path.dentry = dentry;
+        path.mnt = mnt;
 
         smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
-        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
-        smk_ad_setfield_u_fs_path_mnt(&ad, mnt);
+        smk_ad_setfield_u_fs_path(&ad, path);
         return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
 }
 
@@ -784,7 +790,7 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
         } else
                 rc = cap_inode_setxattr(dentry, name, value, size, flags);
 
-        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
+        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
         smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
         if (rc == 0)
@@ -845,7 +851,7 @@ static int smack_inode_getxattr(struct dentry *dentry, const char *name)
 {
         struct smk_audit_info ad;
 
-        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
+        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
         smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
         return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
@@ -877,7 +883,7 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name)
         } else
                 rc = cap_inode_removexattr(dentry, name);
 
-        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
+        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
         smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
         if (rc == 0)
                 rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
@@ -1070,7 +1076,7 @@ static int smack_file_lock(struct file *file, unsigned int cmd)
 {
         struct smk_audit_info ad;
 
-        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
+        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
         smk_ad_setfield_u_fs_path_dentry(&ad, file->f_path.dentry);
         return smk_curacc(file->f_security, MAY_WRITE, &ad);
 }