Merge tag 'ecryptfs-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs

Pull eCryptfs updates from Tyler Hicks:

 - Hardening and fixes for maliciously crafted eCryptfs metadata in the
   lower encrypted file

 - Hardening and fixes for maliciously crafted userspace <-> kernel
   miscdev communications

 - Locking fixes for userspace <-> kernel miscdev communications

 - Fix to display encrypted filename related mount options

 - Clean up address_space_operations and reduce build dependencies by
   moving to filemap_dirty_folio()

 - Get rid of an unnecessary memory allocation in the inode update path

 - Kernel-doc formatting corrections

* tag 'ecryptfs-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs:
  ecryptfs: ecryptfs_kernel.h: clean up kernel-doc comments
  ecryptfs: use filemap_dirty_folio for address space operations
  ecryptfs: avoid heap allocation for inode size write
  ecryptfs: show filename encryption options
  eCryptfs: bound the packet-length peek to the user buffer
  ecryptfs: reject too-small tag 70 packets
  ecryptfs: fix tag 11 packet exact-fit size check
  ecryptfs: pass packet set buffer size to parser
  ecryptfs: hold msg ctx list lock when cleaning daemon queue
  ecryptfs: release message context on send failure
  ecryptfs: reject oversized encrypted_key_size in parse_tag_3_packet

fs/ecryptfs/crypto.c

@@ -1197,7 +1197,7 @@ static int ecryptfs_read_headers_virt(char *page_virt,
 	} else
 		set_default_header_data(crypt_stat);
 	rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
-				       ecryptfs_dentry);
+				       PAGE_SIZE - offset, ecryptfs_dentry);
 out:
 	return rc;
 }

fs/ecryptfs/ecryptfs_kernel.h

@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later */
-/**
+/*
  * eCryptfs: Linux filesystem encryption layer
  * Kernel declarations.
  *
@@ -204,7 +204,7 @@ struct ecryptfs_filename {
 	char dentry_name[ECRYPTFS_ENCRYPTED_DENTRY_NAME_LEN + 1];
 };
 
-/**
+/*
  * This is the primary struct associated with each encrypted file.
  *
  * TODO: cache align/pack?
@@ -255,7 +255,8 @@ struct ecryptfs_inode_info {
 };
 
 /**
- * ecryptfs_global_auth_tok - A key used to encrypt all new files under the mountpoint
+ * struct ecryptfs_global_auth_tok - A key used to encrypt all new files
+ *   under the mountpoint
  * @flags: Status flags
  * @mount_crypt_stat_list: These auth_toks hang off the mount-wide
  *                         cryptographic context. Every time a new
@@ -263,7 +264,6 @@ struct ecryptfs_inode_info {
  *                         the auth_toks on that list to the set of
  *                         auth_toks on the inode's crypt_stat
  * @global_auth_tok_key: The key from the user's keyring for the sig
- * @global_auth_tok: The key contents
  * @sig: The key identifier
  *
  * ecryptfs_global_auth_tok structs refer to authentication token keys
@@ -283,7 +283,7 @@ struct ecryptfs_global_auth_tok {
 };
 
 /**
- * ecryptfs_key_tfm - Persistent key tfm
+ * struct ecryptfs_key_tfm - Persistent key tfm
  * @key_tfm: crypto API handle to the key
  * @key_size: Key size in bytes
  * @key_tfm_mutex: Mutex to ensure only one operation in eCryptfs is
@@ -306,7 +306,7 @@ struct ecryptfs_key_tfm {
 
 extern struct mutex key_tfm_list_mutex;
 
-/**
+/*
  * This struct is to enable a mount-wide passphrase/salt combo. This
  * is more or less a stopgap to provide similar functionality to other
  * crypto filesystems like EncFS or CFS until full policy support is
@@ -580,7 +580,8 @@ int ecryptfs_generate_key_packet_set(char *dest_base,
 				     size_t *len, size_t max);
 int
 ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
-			  unsigned char *src, struct dentry *ecryptfs_dentry);
+			  unsigned char *src, size_t src_size,
+			  struct dentry *ecryptfs_dentry);
 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length);
 ssize_t
 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,

fs/ecryptfs/keystore.c

@@ -894,6 +894,12 @@ ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
 		       "rc = [%d]\n", __func__, rc);
 		goto out;
 	}
+	if (s->parsed_tag_70_packet_size < (ECRYPTFS_SIG_SIZE + 2)) {
+		ecryptfs_printk(KERN_WARNING, "Invalid packet size [%zd]\n",
+				s->parsed_tag_70_packet_size);
+		rc = -EINVAL;
+		goto out;
+	}
 	s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
 					  - ECRYPTFS_SIG_SIZE - 1);
 	if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
@@ -1384,10 +1390,20 @@ parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
 	}
 	(*new_auth_tok)->session_key.encrypted_key_size =
 		(body_size - (ECRYPTFS_SALT_SIZE + 5));
+	/*
+	 * Although encrypted_key_size is copied into the
+	 * encrypted_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES] buffer here,
+	 * it later bounds operations on a smaller buffer:
+	 * decrypt_passphrase_encrypted_session_key() sets decrypted_key_size =
+	 * encrypted_key_size and decrypts into
+	 * decrypted_key[ECRYPTFS_MAX_KEY_BYTES], then memcpy's into
+	 * crypt_stat->key[ECRYPTFS_MAX_KEY_BYTES]. Limit to
+	 * ECRYPTFS_MAX_KEY_BYTES to protect those smaller buffers.
+	 */
 	if ((*new_auth_tok)->session_key.encrypted_key_size
-	    > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
+	    > ECRYPTFS_MAX_KEY_BYTES) {
 		printk(KERN_WARNING "Tag 3 packet contains key larger "
-		       "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
+		       "than ECRYPTFS_MAX_KEY_BYTES\n");
 		rc = -EINVAL;
 		goto out_free;
 	}
@@ -1537,7 +1553,7 @@ parse_tag_11_packet(unsigned char *data, unsigned char *contents,
 	}
 	(*packet_size) += length_size;
 	(*tag_11_contents_size) = (body_size - 14);
-	if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
+	if (unlikely((*packet_size) + body_size > max_packet_size)) {
 		printk(KERN_ERR "Packet size exceeds max\n");
 		rc = -EINVAL;
 		goto out;
@@ -1704,6 +1720,7 @@ decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
  * ecryptfs_parse_packet_set
  * @crypt_stat: The cryptographic context
  * @src: Virtual address of region of memory containing the packets
+ * @src_size: Size of the packet set buffer
  * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
  *
  * Get crypt_stat to have the file's session key if the requisite key
@@ -1714,7 +1731,7 @@ decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
  * conditions.
  */
 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
-			      unsigned char *src,
+			      unsigned char *src, size_t src_size,
 			      struct dentry *ecryptfs_dentry)
 {
 	size_t i = 0;
@@ -1736,7 +1753,11 @@ int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
 	 * added the our &auth_tok_list */
 	next_packet_is_auth_tok_packet = 1;
 	while (next_packet_is_auth_tok_packet) {
-		size_t max_packet_size = ((PAGE_SIZE - 8) - i);
+		size_t max_packet_size;
+
+		if (i >= src_size)
+			break;
+		max_packet_size = src_size - i;
 
 		switch (src[i]) {
 		case ECRYPTFS_TAG_3_PACKET_TYPE:
@@ -1751,12 +1772,16 @@ int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
 				goto out_wipe_list;
 			}
 			i += packet_size;
+			if (i > src_size) {
+				rc = -EIO;
+				goto out_wipe_list;
+			}
 			rc = parse_tag_11_packet((unsigned char *)&src[i],
 						 sig_tmp_space,
 						 ECRYPTFS_SIG_SIZE,
 						 &tag_11_contents_size,
 						 &tag_11_packet_size,
-						 max_packet_size);
+						 src_size - i);
 			if (rc) {
 				ecryptfs_printk(KERN_ERR, "No valid "
 						"(ecryptfs-specific) literal "
@@ -1768,6 +1793,10 @@ int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
 				goto out_wipe_list;
 			}
 			i += tag_11_packet_size;
+			if (i > src_size) {
+				rc = -EIO;
+				goto out_wipe_list;
+			}
 			if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
 				ecryptfs_printk(KERN_ERR, "Expected "
 						"signature of size [%d]; "
@@ -1793,6 +1822,10 @@ int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
 				goto out_wipe_list;
 			}
 			i += packet_size;
+			if (i > src_size) {
+				rc = -EIO;
+				goto out_wipe_list;
+			}
 			crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
 			break;
 		case ECRYPTFS_TAG_11_PACKET_TYPE:

fs/ecryptfs/messaging.c

@@ -166,6 +166,7 @@ int ecryptfs_exorcise_daemon(struct ecryptfs_daemon *daemon)
 		mutex_unlock(&daemon->mux);
 		goto out;
 	}
+	mutex_lock(&ecryptfs_msg_ctx_lists_mux);
 	list_for_each_entry_safe(msg_ctx, msg_ctx_tmp,
 				 &daemon->msg_ctx_out_queue, daemon_out_list) {
 		list_del(&msg_ctx->daemon_out_list);
@@ -174,6 +175,7 @@ int ecryptfs_exorcise_daemon(struct ecryptfs_daemon *daemon)
 		       "the out queue of a dying daemon\n", __func__);
 		ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
 	}
+	mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
 	hlist_del(&daemon->euid_chain);
 	mutex_unlock(&daemon->mux);
 	kfree_sensitive(daemon);
@@ -284,9 +286,16 @@ ecryptfs_send_message_locked(char *data, int data_len, u8 msg_type,
 	mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
 	rc = ecryptfs_send_miscdev(data, data_len, *msg_ctx, msg_type, 0,
 				   daemon);
-	if (rc)
+	if (rc) {
 		printk(KERN_ERR "%s: Error attempting to send message to "
 		       "userspace daemon; rc = [%d]\n", __func__, rc);
+		mutex_lock(&ecryptfs_msg_ctx_lists_mux);
+		mutex_lock(&(*msg_ctx)->mux);
+		ecryptfs_msg_ctx_alloc_to_free(*msg_ctx);
+		mutex_unlock(&(*msg_ctx)->mux);
+		mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+		*msg_ctx = NULL;
+	}
 out:
 	return rc;
 }

fs/ecryptfs/miscdev.c

@@ -360,7 +360,7 @@ ecryptfs_miscdev_write(struct file *file, const char __user *buf,
 	u32 seq;
 	size_t packet_size, packet_size_length;
 	char *data;
-	unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE];
+	unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE] = { };
 	ssize_t rc;
 
 	if (count == 0) {
@@ -376,7 +376,8 @@ ecryptfs_miscdev_write(struct file *file, const char __user *buf,
 	}
 
 	if (copy_from_user(packet_size_peek, &buf[PKT_LEN_OFFSET],
-			   sizeof(packet_size_peek))) {
+			   min_t(size_t, count - PKT_LEN_OFFSET,
+				 sizeof(packet_size_peek)))) {
 		printk(KERN_WARNING "%s: Error while inspecting packet size\n",
 		       __func__);
 		return -EFAULT;

fs/ecryptfs/mmap.c

@@ -355,24 +355,17 @@ static int ecryptfs_write_begin(const struct kiocb *iocb,
  */
 static int ecryptfs_write_inode_size_to_header(struct inode *ecryptfs_inode)
 {
-	char *file_size_virt;
+	__be64 file_size;
 	int rc;
 
-	file_size_virt = kmalloc(sizeof(u64), GFP_KERNEL);
-	if (!file_size_virt) {
-		rc = -ENOMEM;
-		goto out;
-	}
-	put_unaligned_be64(i_size_read(ecryptfs_inode), file_size_virt);
-	rc = ecryptfs_write_lower(ecryptfs_inode, file_size_virt, 0,
-				  sizeof(u64));
-	kfree(file_size_virt);
+	file_size = cpu_to_be64(i_size_read(ecryptfs_inode));
+	rc = ecryptfs_write_lower(ecryptfs_inode, (char *)&file_size, 0,
+				  sizeof(file_size));
 	if (rc < 0)
 		printk(KERN_ERR "%s: Error writing file size to header; "
 		       "rc = [%d]\n", __func__, rc);
 	else
 		rc = 0;
-out:
 	return rc;
 }
 
@@ -510,21 +503,8 @@ static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)
 	return block;
 }
 
-#include <linux/buffer_head.h>
-
 const struct address_space_operations ecryptfs_aops = {
-	/*
-	 * XXX: This is pretty broken for multiple reasons: ecryptfs does not
-	 * actually use buffer_heads, and ecryptfs will crash without
-	 * CONFIG_BLOCK.  But it matches the behavior before the default for
-	 * address_space_operations without the ->dirty_folio method was
-	 * cleaned up, so this is the best we can do without maintainer
-	 * feedback.
-	 */
-#ifdef CONFIG_BLOCK
-	.dirty_folio	= block_dirty_folio,
-	.invalidate_folio = block_invalidate_folio,
-#endif
+	.dirty_folio	= filemap_dirty_folio,
 	.writepages = ecryptfs_writepages,
 	.read_folio = ecryptfs_read_folio,
 	.write_begin = ecryptfs_write_begin,

fs/ecryptfs/super.c

@@ -150,6 +150,13 @@ static int ecryptfs_show_options(struct seq_file *m, struct dentry *root)
 	if (mount_crypt_stat->global_default_cipher_key_size)
 		seq_printf(m, ",ecryptfs_key_bytes=%zd",
 			   mount_crypt_stat->global_default_cipher_key_size);
+	if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
+		seq_printf(m, ",ecryptfs_fn_cipher=%s",
+			   mount_crypt_stat->global_default_fn_cipher_name);
+		if (mount_crypt_stat->global_default_fn_cipher_key_bytes)
+			seq_printf(m, ",ecryptfs_fn_key_bytes=%zd",
+				   mount_crypt_stat->global_default_fn_cipher_key_bytes);
+	}
 	if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)
 		seq_printf(m, ",ecryptfs_passthrough");
 	if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)