Merge tag 'fscrypt_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/fscrypt (677375ce) · Commits · 戴 / test

MAINTAINERS

+4 −2

Original line number	Diff line number	Diff line
		@@ -5417,10 +5417,12 @@ F: Documentation/filesystems/caching/
		F: fs/fscache/
		F: include/linux/fscache*.h

		FS-CRYPTO: FILE SYSTEM LEVEL ENCRYPTION SUPPORT
		FSCRYPT: FILE SYSTEM LEVEL ENCRYPTION SUPPORT
		M: Theodore Y. Ts'o <tytso@mit.edu>
		M: Jaegeuk Kim <jaegeuk@kernel.org>
		L: linux-fsdevel@vger.kernel.org
		L: linux-fscrypt@vger.kernel.org
		Q: https://patchwork.kernel.org/project/linux-fscrypt/list/
		T: git git://git.kernel.org/pub/scm/linux/kernel/git/tytso/fscrypt.git
		S: Supported
		F: fs/crypto/
		F: include/linux/fscrypt*.h

fs/crypto/fname.c

+70 −20

Original line number	Diff line number	Diff line
		@@ -159,6 +159,8 @@ static int fname_decrypt(struct inode *inode,
		static const char *lookup_table =
		"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";

		#define BASE64_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3)

		/**
		* digest_encode() -
		*
		@@ -230,11 +232,14 @@ EXPORT_SYMBOL(fscrypt_fname_encrypted_size);
		int fscrypt_fname_alloc_buffer(const struct inode *inode,
		u32 ilen, struct fscrypt_str *crypto_str)
		{
		unsigned int olen = fscrypt_fname_encrypted_size(inode, ilen);
		u32 olen = fscrypt_fname_encrypted_size(inode, ilen);
		const u32 max_encoded_len =
		max_t(u32, BASE64_CHARS(FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE),
		1 + BASE64_CHARS(sizeof(struct fscrypt_digested_name)));

		crypto_str->len = olen;
		if (olen < FS_FNAME_CRYPTO_DIGEST_SIZE * 2)
		olen = FS_FNAME_CRYPTO_DIGEST_SIZE * 2;
		olen = max(olen, max_encoded_len);

		/*
		* Allocated buffer can hold one more character to null-terminate the
		* string
		@@ -266,6 +271,10 @@ EXPORT_SYMBOL(fscrypt_fname_free_buffer);
		*
		* The caller must have allocated sufficient memory for the @oname string.
		*
		* If the key is available, we'll decrypt the disk name; otherwise, we'll encode
		* it for presentation. Short names are directly base64-encoded, while long
		* names are encoded in fscrypt_digested_name format.
		*
		* Return: 0 on success, -errno on failure
		*/
		int fscrypt_fname_disk_to_usr(struct inode *inode,
		@@ -274,7 +283,7 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
		struct fscrypt_str *oname)
		{
		const struct qstr qname = FSTR_TO_QSTR(iname);
		char buf[24];
		struct fscrypt_digested_name digested_name;

		if (fscrypt_is_dot_dotdot(&qname)) {
		oname->name[0] = '.';
		@@ -289,20 +298,24 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
		if (inode->i_crypt_info)
		return fname_decrypt(inode, iname, oname);

		if (iname->len <= FS_FNAME_CRYPTO_DIGEST_SIZE) {
		if (iname->len <= FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE) {
		oname->len = digest_encode(iname->name, iname->len,
		oname->name);
		return 0;
		}
		if (hash) {
		memcpy(buf, &hash, 4);
		memcpy(buf + 4, &minor_hash, 4);
		digested_name.hash = hash;
		digested_name.minor_hash = minor_hash;
		} else {
		memset(buf, 0, 8);
		digested_name.hash = 0;
		digested_name.minor_hash = 0;
		}
		memcpy(buf + 8, iname->name + iname->len - 16, 16);
		memcpy(digested_name.digest,
		FSCRYPT_FNAME_DIGEST(iname->name, iname->len),
		FSCRYPT_FNAME_DIGEST_SIZE);
		oname->name[0] = '_';
		oname->len = 1 + digest_encode(buf, 24, oname->name + 1);
		oname->len = 1 + digest_encode((const char *)&digested_name,
		sizeof(digested_name), oname->name + 1);
		return 0;
		}
		EXPORT_SYMBOL(fscrypt_fname_disk_to_usr);
		@@ -336,10 +349,35 @@ int fscrypt_fname_usr_to_disk(struct inode *inode,
		}
		EXPORT_SYMBOL(fscrypt_fname_usr_to_disk);

		/**
		* fscrypt_setup_filename() - prepare to search a possibly encrypted directory
		* @dir: the directory that will be searched
		* @iname: the user-provided filename being searched for
		* @lookup: 1 if we're allowed to proceed without the key because it's
		* ->lookup() or we're finding the dir_entry for deletion; 0 if we cannot
		* proceed without the key because we're going to create the dir_entry.
		* @fname: the filename information to be filled in
		*
		* Given a user-provided filename @iname, this function sets @fname->disk_name
		* to the name that would be stored in the on-disk directory entry, if possible.
		* If the directory is unencrypted this is simply @iname. Else, if we have the
		* directory's encryption key, then @iname is the plaintext, so we encrypt it to
		* get the disk_name.
		*
		* Else, for keyless @lookup operations, @iname is the presented ciphertext, so
		* we decode it to get either the ciphertext disk_name (for short names) or the
		* fscrypt_digested_name (for long names). Non-@lookup operations will be
		* impossible in this case, so we fail them with ENOKEY.
		*
		* If successful, fscrypt_free_filename() must be called later to clean up.
		*
		* Return: 0 on success, -errno on failure
		*/
		int fscrypt_setup_filename(struct inode dir, const struct qstr iname,
		int lookup, struct fscrypt_name *fname)
		{
		int ret = 0, bigname = 0;
		int ret;
		int digested;

		memset(fname, 0, sizeof(struct fscrypt_name));
		fname->usr_fname = iname;
		@@ -373,25 +411,37 @@ int fscrypt_setup_filename(struct inode dir, const struct qstr iname,
		* We don't have the key and we are doing a lookup; decode the
		* user-supplied name
		*/
		if (iname->name[0] == '_')
		bigname = 1;
		if ((bigname && (iname->len != 33)) \|\| (!bigname && (iname->len > 43)))
		if (iname->name[0] == '_') {
		if (iname->len !=
		1 + BASE64_CHARS(sizeof(struct fscrypt_digested_name)))
		return -ENOENT;
		digested = 1;
		} else {
		if (iname->len >
		BASE64_CHARS(FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE))
		return -ENOENT;
		digested = 0;
		}

		fname->crypto_buf.name = kmalloc(32, GFP_KERNEL);
		fname->crypto_buf.name =
		kmalloc(max_t(size_t, FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE,
		sizeof(struct fscrypt_digested_name)),
		GFP_KERNEL);
		if (fname->crypto_buf.name == NULL)
		return -ENOMEM;

		ret = digest_decode(iname->name + bigname, iname->len - bigname,
		ret = digest_decode(iname->name + digested, iname->len - digested,
		fname->crypto_buf.name);
		if (ret < 0) {
		ret = -ENOENT;
		goto errout;
		}
		fname->crypto_buf.len = ret;
		if (bigname) {
		memcpy(&fname->hash, fname->crypto_buf.name, 4);
		memcpy(&fname->minor_hash, fname->crypto_buf.name + 4, 4);
		if (digested) {
		const struct fscrypt_digested_name *n =
		(const void *)fname->crypto_buf.name;
		fname->hash = n->hash;
		fname->minor_hash = n->minor_hash;
		} else {
		fname->disk_name.name = fname->crypto_buf.name;
		fname->disk_name.len = fname->crypto_buf.len;

fs/crypto/fscrypt_private.h

+0 −13

Original line number	Diff line number	Diff line
		@@ -13,8 +13,6 @@

		#include <linux/fscrypt_supp.h>

		#define FS_FNAME_CRYPTO_DIGEST_SIZE 32

		/* Encryption parameters */
		#define FS_XTS_TWEAK_SIZE 16
		#define FS_AES_128_ECB_KEY_SIZE 16
		@@ -22,10 +20,6 @@
		#define FS_AES_256_CBC_KEY_SIZE 32
		#define FS_AES_256_CTS_KEY_SIZE 32
		#define FS_AES_256_XTS_KEY_SIZE 64
		#define FS_MAX_KEY_SIZE 64

		#define FS_KEY_DESC_PREFIX "fscrypt:"
		#define FS_KEY_DESC_PREFIX_SIZE 8

		#define FS_KEY_DERIVATION_NONCE_SIZE 16

		@@ -51,13 +45,6 @@ struct fscrypt_context {

		#define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1

		/* This is passed in from userspace into the kernel keyring */
		struct fscrypt_key {
		u32 mode;
		u8 raw[FS_MAX_KEY_SIZE];
		u32 size;
		} __packed;

		/*
		* A pointer to this structure is stored in the file system's in-core
		* representation of an inode.

fs/crypto/keyinfo.c

+0 −3

Original line number	Diff line number	Diff line
		@@ -183,9 +183,6 @@ int fscrypt_get_encryption_info(struct inode *inode)
		if (res)
		return res;

		if (!inode->i_sb->s_cop->get_context)
		return -EOPNOTSUPP;

		res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
		if (res < 0) {
		if (!fscrypt_dummy_context_enabled(inode) \|\|

fs/crypto/policy.c

+69 −29

Original line number	Diff line number	Diff line
		@@ -34,9 +34,6 @@ static int create_encryption_context_from_policy(struct inode *inode,
		{
		struct fscrypt_context ctx;

		if (!inode->i_sb->s_cop->set_context)
		return -EOPNOTSUPP;

		ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
		memcpy(ctx.master_key_descriptor, policy->master_key_descriptor,
		FS_KEY_DESCRIPTOR_SIZE);
		@@ -87,8 +84,6 @@ int fscrypt_ioctl_set_policy(struct file filp, const void __user arg)
		if (ret == -ENODATA) {
		if (!S_ISDIR(inode->i_mode))
		ret = -ENOTDIR;
		else if (!inode->i_sb->s_cop->empty_dir)
		ret = -EOPNOTSUPP;
		else if (!inode->i_sb->s_cop->empty_dir(inode))
		ret = -ENOTEMPTY;
		else
		@@ -118,8 +113,7 @@ int fscrypt_ioctl_get_policy(struct file filp, void __user arg)
		struct fscrypt_policy policy;
		int res;

		if (!inode->i_sb->s_cop->get_context \|\|
		!inode->i_sb->s_cop->is_encrypted(inode))
		if (!inode->i_sb->s_cop->is_encrypted(inode))
		return -ENODATA;

		res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
		@@ -143,27 +137,61 @@ int fscrypt_ioctl_get_policy(struct file filp, void __user arg)
		}
		EXPORT_SYMBOL(fscrypt_ioctl_get_policy);

		/**
		* fscrypt_has_permitted_context() - is a file's encryption policy permitted
		* within its directory?
		*
		* @parent: inode for parent directory
		* @child: inode for file being looked up, opened, or linked into @parent
		*
		* Filesystems must call this before permitting access to an inode in a
		* situation where the parent directory is encrypted (either before allowing
		* ->lookup() to succeed, or for a regular file before allowing it to be opened)
		* and before any operation that involves linking an inode into an encrypted
		* directory, including link, rename, and cross rename. It enforces the
		* constraint that within a given encrypted directory tree, all files use the
		* same encryption policy. The pre-access check is needed to detect potentially
		* malicious offline violations of this constraint, while the link and rename
		* checks are needed to prevent online violations of this constraint.
		*
		* Return: 1 if permitted, 0 if forbidden. If forbidden, the caller must fail
		* the filesystem operation with EPERM.
		*/
		int fscrypt_has_permitted_context(struct inode parent, struct inode child)
		{
		struct fscrypt_info parent_ci, child_ci;
		const struct fscrypt_operations *cops = parent->i_sb->s_cop;
		const struct fscrypt_info parent_ci, child_ci;
		struct fscrypt_context parent_ctx, child_ctx;
		int res;

		if ((parent == NULL) \|\| (child == NULL)) {
		printk(KERN_ERR "parent %p child %p\n", parent, child);
		BUG_ON(1);
		}

		/* No restrictions on file types which are never encrypted */
		if (!S_ISREG(child->i_mode) && !S_ISDIR(child->i_mode) &&
		!S_ISLNK(child->i_mode))
		return 1;

		/* no restrictions if the parent directory is not encrypted */
		if (!parent->i_sb->s_cop->is_encrypted(parent))
		/* No restrictions if the parent directory is unencrypted */
		if (!cops->is_encrypted(parent))
		return 1;
		/* if the child directory is not encrypted, this is always a problem */
		if (!parent->i_sb->s_cop->is_encrypted(child))

		/* Encrypted directories must not contain unencrypted files */
		if (!cops->is_encrypted(child))
		return 0;

		/*
		* Both parent and child are encrypted, so verify they use the same
		* encryption policy. Compare the fscrypt_info structs if the keys are
		* available, otherwise retrieve and compare the fscrypt_contexts.
		*
		* Note that the fscrypt_context retrieval will be required frequently
		* when accessing an encrypted directory tree without the key.
		* Performance-wise this is not a big deal because we already don't
		* really optimize for file access without the key (to the extent that
		* such access is even possible), given that any attempted access
		* already causes a fscrypt_context retrieval and keyring search.
		*
		* In any case, if an unexpected error occurs, fall back to "forbidden".
		*/

		res = fscrypt_get_encryption_info(parent);
		if (res)
		return 0;
		@@ -172,17 +200,32 @@ int fscrypt_has_permitted_context(struct inode parent, struct inode child)
		return 0;
		parent_ci = parent->i_crypt_info;
		child_ci = child->i_crypt_info;
		if (!parent_ci && !child_ci)
		return 1;
		if (!parent_ci \|\| !child_ci)
		return 0;

		return (memcmp(parent_ci->ci_master_key,
		child_ci->ci_master_key,
		if (parent_ci && child_ci) {
		return memcmp(parent_ci->ci_master_key, child_ci->ci_master_key,
		FS_KEY_DESCRIPTOR_SIZE) == 0 &&
		(parent_ci->ci_data_mode == child_ci->ci_data_mode) &&
		(parent_ci->ci_filename_mode == child_ci->ci_filename_mode) &&
		(parent_ci->ci_flags == child_ci->ci_flags));
		(parent_ci->ci_filename_mode ==
		child_ci->ci_filename_mode) &&
		(parent_ci->ci_flags == child_ci->ci_flags);
		}

		res = cops->get_context(parent, &parent_ctx, sizeof(parent_ctx));
		if (res != sizeof(parent_ctx))
		return 0;

		res = cops->get_context(child, &child_ctx, sizeof(child_ctx));
		if (res != sizeof(child_ctx))
		return 0;

		return memcmp(parent_ctx.master_key_descriptor,
		child_ctx.master_key_descriptor,
		FS_KEY_DESCRIPTOR_SIZE) == 0 &&
		(parent_ctx.contents_encryption_mode ==
		child_ctx.contents_encryption_mode) &&
		(parent_ctx.filenames_encryption_mode ==
		child_ctx.filenames_encryption_mode) &&
		(parent_ctx.flags == child_ctx.flags);
		}
		EXPORT_SYMBOL(fscrypt_has_permitted_context);

		@@ -202,9 +245,6 @@ int fscrypt_inherit_context(struct inode parent, struct inode child,
		struct fscrypt_info *ci;
		int res;

		if (!parent->i_sb->s_cop->set_context)
		return -EOPNOTSUPP;

		res = fscrypt_get_encryption_info(parent);
		if (res < 0)
		return res;

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