Linux-libre 4.8.2-gnupck-4.8.2-gnu

3 files changed, 44 insertions, 7 deletions

diff --git a/security/smack/smack.h b/security/smack/smack.h
index 6c91156ae..26e58f180 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -90,9 +90,15 @@ struct superblock_smack {
 	struct smack_known	*smk_floor;
 	struct smack_known	*smk_hat;
 	struct smack_known	*smk_default;
-	int			smk_initialized;
+	int			smk_flags;
 };
 
+/*
+ * Superblock flags
+ */
+#define SMK_SB_INITIALIZED	0x01
+#define SMK_SB_UNTRUSTED	0x02
+
 struct socket_smack {
 	struct smack_known	*smk_out;	/* outbound label */
 	struct smack_known	*smk_in;	/* inbound label */
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index a283f9e79..23e5808a0 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -413,7 +413,7 @@ void smk_insert_entry(struct smack_known *skp)
 	unsigned int hash;
 	struct hlist_head *head;
 
-	hash = full_name_hash(skp->smk_known, strlen(skp->smk_known));
+	hash = full_name_hash(NULL, skp->smk_known, strlen(skp->smk_known));
 	head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
 
 	hlist_add_head_rcu(&skp->smk_hashed, head);
@@ -433,7 +433,7 @@ struct smack_known *smk_find_entry(const char *string)
 	struct hlist_head *head;
 	struct smack_known *skp;
 
-	hash = full_name_hash(string, strlen(string));
+	hash = full_name_hash(NULL, string, strlen(string));
 	head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
 
 	hlist_for_each_entry_rcu(skp, head, smk_hashed)
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 6777295f4..87a9741b0 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -549,7 +549,7 @@ static int smack_sb_alloc_security(struct super_block *sb)
 	sbsp->smk_floor = &smack_known_floor;
 	sbsp->smk_hat = &smack_known_hat;
 	/*
-	 * smk_initialized will be zero from kzalloc.
+	 * SMK_SB_INITIALIZED will be zero from kzalloc.
 	 */
 	sb->s_security = sbsp;
 
@@ -766,10 +766,10 @@ static int smack_set_mnt_opts(struct super_block *sb,
 	int num_opts = opts->num_mnt_opts;
 	int transmute = 0;
 
-	if (sp->smk_initialized)
+	if (sp->smk_flags & SMK_SB_INITIALIZED)
 		return 0;
 
-	sp->smk_initialized = 1;
+	sp->smk_flags |= SMK_SB_INITIALIZED;
 
 	for (i = 0; i < num_opts; i++) {
 		switch (opts->mnt_opts_flags[i]) {
@@ -821,6 +821,17 @@ static int smack_set_mnt_opts(struct super_block *sb,
 		skp = smk_of_current();
 		sp->smk_root = skp;
 		sp->smk_default = skp;
+		/*
+		 * For a handful of fs types with no user-controlled
+		 * backing store it's okay to trust security labels
+		 * in the filesystem. The rest are untrusted.
+		 */
+		if (sb->s_user_ns != &init_user_ns &&
+		    sb->s_magic != SYSFS_MAGIC && sb->s_magic != TMPFS_MAGIC &&
+		    sb->s_magic != RAMFS_MAGIC) {
+			transmute = 1;
+			sp->smk_flags |= SMK_SB_UNTRUSTED;
+		}
 	}
 
 	/*
@@ -908,6 +919,7 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm)
 	struct inode *inode = file_inode(bprm->file);
 	struct task_smack *bsp = bprm->cred->security;
 	struct inode_smack *isp;
+	struct superblock_smack *sbsp;
 	int rc;
 
 	if (bprm->cred_prepared)
@@ -917,6 +929,11 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm)
 	if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task)
 		return 0;
 
+	sbsp = inode->i_sb->s_security;
+	if ((sbsp->smk_flags & SMK_SB_UNTRUSTED) &&
+	    isp->smk_task != sbsp->smk_root)
+		return 0;
+
 	if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
 		struct task_struct *tracer;
 		rc = 0;
@@ -1203,6 +1220,7 @@ static int smack_inode_rename(struct inode *old_inode,
  */
 static int smack_inode_permission(struct inode *inode, int mask)
 {
+	struct superblock_smack *sbsp = inode->i_sb->s_security;
 	struct smk_audit_info ad;
 	int no_block = mask & MAY_NOT_BLOCK;
 	int rc;
@@ -1214,6 +1232,11 @@ static int smack_inode_permission(struct inode *inode, int mask)
 	if (mask == 0)
 		return 0;
 
+	if (sbsp->smk_flags & SMK_SB_UNTRUSTED) {
+		if (smk_of_inode(inode) != sbsp->smk_root)
+			return -EACCES;
+	}
+
 	/* May be droppable after audit */
 	if (no_block)
 		return -ECHILD;
@@ -1708,6 +1731,7 @@ static int smack_mmap_file(struct file *file,
 	struct task_smack *tsp;
 	struct smack_known *okp;
 	struct inode_smack *isp;
+	struct superblock_smack *sbsp;
 	int may;
 	int mmay;
 	int tmay;
@@ -1719,6 +1743,10 @@ static int smack_mmap_file(struct file *file,
 	isp = file_inode(file)->i_security;
 	if (isp->smk_mmap == NULL)
 		return 0;
+	sbsp = file_inode(file)->i_sb->s_security;
+	if (sbsp->smk_flags & SMK_SB_UNTRUSTED &&
+	    isp->smk_mmap != sbsp->smk_root)
+		return -EACCES;
 	mkp = isp->smk_mmap;
 
 	tsp = current_security();
@@ -2227,6 +2255,9 @@ static int smack_task_kill(struct task_struct *p, struct siginfo *info,
 	struct smack_known *tkp = smk_of_task_struct(p);
 	int rc;
 
+	if (!sig)
+		return 0; /* null signal; existence test */
+
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
 	smk_ad_setfield_u_tsk(&ad, p);
 	/*
@@ -3992,7 +4023,7 @@ access_check:
 		rc = smk_bu_note("IPv4 delivery", skp, ssp->smk_in,
 					MAY_WRITE, rc);
 		if (rc != 0)
-			netlbl_skbuff_err(skb, rc, 0);
+			netlbl_skbuff_err(skb, sk->sk_family, rc, 0);
 		break;
 #if IS_ENABLED(CONFIG_IPV6)
 	case PF_INET6: