diff -drupN a/fs/crypto/fname.c b/fs/crypto/fname.c --- a/fs/crypto/fname.c 2018-08-06 17:23:04.000000000 +0300 +++ b/fs/crypto/fname.c 2022-06-12 05:28:14.000000000 +0300 @@ -12,57 +12,46 @@ #include #include -#include +#include +#include "fscrypt_private.h" -/** - * fname_crypt_complete() - completion callback for filename crypto - * @req: The asynchronous cipher request context - * @res: The result of the cipher operation - */ -static void fname_crypt_complete(struct crypto_async_request *req, int res) +static inline bool fscrypt_is_dot_dotdot(const struct qstr *str) { - struct fscrypt_completion_result *ecr = req->data; + if (str->len == 1 && str->name[0] == '.') + return true; - if (res == -EINPROGRESS) - return; - ecr->res = res; - complete(&ecr->completion); + if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.') + return true; + + return false; } /** * fname_encrypt() - encrypt a filename * - * The caller must have allocated sufficient memory for the @oname string. + * The output buffer must be at least as large as the input buffer. + * Any extra space is filled with NUL padding before encryption. * * Return: 0 on success, -errno on failure */ -static int fname_encrypt(struct inode *inode, - const struct qstr *iname, struct fscrypt_str *oname) +int fname_encrypt(struct inode *inode, const struct qstr *iname, + u8 *out, unsigned int olen) { struct skcipher_request *req = NULL; - DECLARE_FS_COMPLETION_RESULT(ecr); - struct fscrypt_info *ci = inode->i_crypt_info; - struct crypto_skcipher *tfm = ci->ci_ctfm; + DECLARE_CRYPTO_WAIT(wait); + struct crypto_skcipher *tfm = inode->i_crypt_info->ci_ctfm; int res = 0; char iv[FS_CRYPTO_BLOCK_SIZE]; struct scatterlist sg; - int padding = 4 << (ci->ci_flags & FS_POLICY_FLAGS_PAD_MASK); - unsigned int lim; - unsigned int cryptlen; - - lim = inode->i_sb->s_cop->max_namelen(inode); - if (iname->len <= 0 || iname->len > lim) - return -EIO; /* * Copy the filename to the output buffer for encrypting in-place and * pad it with the needed number of NUL bytes. */ - cryptlen = max_t(unsigned int, iname->len, FS_CRYPTO_BLOCK_SIZE); - cryptlen = round_up(cryptlen, padding); - cryptlen = min(cryptlen, lim); - memcpy(oname->name, iname->name, iname->len); - memset(oname->name + iname->len, 0, cryptlen - iname->len); + if (WARN_ON(olen < iname->len)) + return -ENOBUFS; + memcpy(out, iname->name, iname->len); + memset(out + iname->len, 0, olen - iname->len); /* Initialize the IV */ memset(iv, 0, FS_CRYPTO_BLOCK_SIZE); @@ -76,17 +65,12 @@ static int fname_encrypt(struct inode *i } skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, - fname_crypt_complete, &ecr); - sg_init_one(&sg, oname->name, cryptlen); - skcipher_request_set_crypt(req, &sg, &sg, cryptlen, iv); + crypto_req_done, &wait); + sg_init_one(&sg, out, olen); + skcipher_request_set_crypt(req, &sg, &sg, olen, iv); /* Do the encryption */ - res = crypto_skcipher_encrypt(req); - if (res == -EINPROGRESS || res == -EBUSY) { - /* Request is being completed asynchronously; wait for it */ - wait_for_completion(&ecr.completion); - res = ecr.res; - } + res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait); skcipher_request_free(req); if (res < 0) { printk_ratelimited(KERN_ERR @@ -94,7 +78,6 @@ static int fname_encrypt(struct inode *i return res; } - oname->len = cryptlen; return 0; } @@ -110,7 +93,7 @@ static int fname_decrypt(struct inode *i struct fscrypt_str *oname) { struct skcipher_request *req = NULL; - DECLARE_FS_COMPLETION_RESULT(ecr); + DECLARE_CRYPTO_WAIT(wait); struct scatterlist src_sg, dst_sg; struct fscrypt_info *ci = inode->i_crypt_info; struct crypto_skcipher *tfm = ci->ci_ctfm; @@ -131,7 +114,7 @@ static int fname_decrypt(struct inode *i } skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, - fname_crypt_complete, &ecr); + crypto_req_done, &wait); /* Initialize IV */ memset(iv, 0, FS_CRYPTO_BLOCK_SIZE); @@ -140,11 +123,7 @@ static int fname_decrypt(struct inode *i sg_init_one(&src_sg, iname->name, iname->len); sg_init_one(&dst_sg, oname->name, oname->len); skcipher_request_set_crypt(req, &src_sg, &dst_sg, iname->len, iv); - res = crypto_skcipher_decrypt(req); - if (res == -EINPROGRESS || res == -EBUSY) { - wait_for_completion(&ecr.completion); - res = ecr.res; - } + res = crypto_wait_req(crypto_skcipher_decrypt(req), &wait); skcipher_request_free(req); if (res < 0) { printk_ratelimited(KERN_ERR @@ -159,6 +138,8 @@ static int fname_decrypt(struct inode *i static const char *lookup_table = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,"; +#define BASE64_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3) + /** * digest_encode() - * @@ -209,47 +190,52 @@ static int digest_decode(const char *src return cp - dst; } -u32 fscrypt_fname_encrypted_size(struct inode *inode, u32 ilen) +bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len, + u32 max_len, u32 *encrypted_len_ret) { - int padding = 32; - struct fscrypt_info *ci = inode->i_crypt_info; + int padding = 4 << (inode->i_crypt_info->ci_flags & + FS_POLICY_FLAGS_PAD_MASK); + u32 encrypted_len; - if (ci) - padding = 4 << (ci->ci_flags & FS_POLICY_FLAGS_PAD_MASK); - ilen = max(ilen, (u32)FS_CRYPTO_BLOCK_SIZE); - return round_up(ilen, padding); + if (orig_len > max_len) + return false; + encrypted_len = max(orig_len, (u32)FS_CRYPTO_BLOCK_SIZE); + encrypted_len = round_up(encrypted_len, padding); + *encrypted_len_ret = min(encrypted_len, max_len); + return true; } -EXPORT_SYMBOL(fscrypt_fname_encrypted_size); /** - * fscrypt_fname_crypto_alloc_obuff() - + * fscrypt_fname_alloc_buffer - allocate a buffer for presented filenames * - * Allocates an output buffer that is sufficient for the crypto operation - * specified by the context and the direction. + * Allocate a buffer that is large enough to hold any decrypted or encoded + * filename (null-terminated), for the given maximum encrypted filename length. + * + * Return: 0 on success, -errno on failure */ -int fscrypt_fname_alloc_buffer(struct inode *inode, - u32 ilen, struct fscrypt_str *crypto_str) +int fscrypt_fname_alloc_buffer(const struct inode *inode, + u32 max_encrypted_len, + struct fscrypt_str *crypto_str) { - unsigned int 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))); + u32 max_presented_len; - crypto_str->len = olen; - if (olen < FS_FNAME_CRYPTO_DIGEST_SIZE * 2) - olen = FS_FNAME_CRYPTO_DIGEST_SIZE * 2; - /* - * Allocated buffer can hold one more character to null-terminate the - * string - */ - crypto_str->name = kmalloc(olen + 1, GFP_NOFS); - if (!(crypto_str->name)) + max_presented_len = max(max_encoded_len, max_encrypted_len); + + crypto_str->name = kmalloc(max_presented_len + 1, GFP_NOFS); + if (!crypto_str->name) return -ENOMEM; + crypto_str->len = max_presented_len; return 0; } EXPORT_SYMBOL(fscrypt_fname_alloc_buffer); /** - * fscrypt_fname_crypto_free_buffer() - + * fscrypt_fname_free_buffer - free the buffer for presented filenames * - * Frees the buffer allocated for crypto operation. + * Free the buffer allocated by fscrypt_fname_alloc_buffer(). */ void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str) { @@ -266,6 +252,10 @@ 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 +264,7 @@ int fscrypt_fname_disk_to_usr(struct ino 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] = '.'; @@ -289,63 +279,62 @@ int fscrypt_fname_disk_to_usr(struct ino 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 - 17) & ~15), 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); /** - * fscrypt_fname_usr_to_disk() - converts a filename from user space to disk - * space + * 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 * - * The caller must have allocated sufficient memory for the @oname string. + * 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_fname_usr_to_disk(struct inode *inode, - const struct qstr *iname, - struct fscrypt_str *oname) -{ - if (fscrypt_is_dot_dotdot(iname)) { - oname->name[0] = '.'; - oname->name[iname->len - 1] = '.'; - oname->len = iname->len; - return 0; - } - if (inode->i_crypt_info) - return fname_encrypt(inode, iname, oname); - /* - * Without a proper key, a user is not allowed to modify the filenames - * in a directory. Consequently, a user space name cannot be mapped to - * a disk-space name - */ - return -ENOKEY; -} -EXPORT_SYMBOL(fscrypt_fname_usr_to_disk); - 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; - if (!dir->i_sb->s_cop->is_encrypted(dir) || - fscrypt_is_dot_dotdot(iname)) { + if (!IS_ENCRYPTED(dir) || fscrypt_is_dot_dotdot(iname)) { fname->disk_name.name = (unsigned char *)iname->name; fname->disk_name.len = iname->len; return 0; @@ -355,11 +344,17 @@ int fscrypt_setup_filename(struct inode return ret; if (dir->i_crypt_info) { - ret = fscrypt_fname_alloc_buffer(dir, iname->len, - &fname->crypto_buf); - if (ret) - return ret; - ret = fname_encrypt(dir, iname, &fname->crypto_buf); + if (!fscrypt_fname_encrypted_size(dir, iname->len, + dir->i_sb->s_cop->max_namelen(dir), + &fname->crypto_buf.len)) + return -ENAMETOOLONG; + fname->crypto_buf.name = kmalloc(fname->crypto_buf.len, + GFP_NOFS); + if (!fname->crypto_buf.name) + return -ENOMEM; + + ret = fname_encrypt(dir, iname, fname->crypto_buf.name, + fname->crypto_buf.len); if (ret) goto errout; fname->disk_name.name = fname->crypto_buf.name; @@ -373,25 +368,37 @@ int fscrypt_setup_filename(struct inode * 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))) - return -ENOENT; + 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; @@ -399,16 +406,7 @@ int fscrypt_setup_filename(struct inode return 0; errout: - fscrypt_fname_free_buffer(&fname->crypto_buf); + kfree(fname->crypto_buf.name); return ret; } EXPORT_SYMBOL(fscrypt_setup_filename); - -void fscrypt_free_filename(struct fscrypt_name *fname) -{ - kfree(fname->crypto_buf.name); - fname->crypto_buf.name = NULL; - fname->usr_fname = NULL; - fname->disk_name.name = NULL; -} -EXPORT_SYMBOL(fscrypt_free_filename);