diff options
Diffstat (limited to 'fs/crypto/fname.c')
-rw-r--r-- | fs/crypto/fname.c | 246 |
1 files changed, 96 insertions, 150 deletions
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index 8606da1df0aa..3da3707c10e3 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -12,90 +12,69 @@ */ #include <linux/scatterlist.h> -#include <linux/ratelimit.h> +#include <crypto/skcipher.h> #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); + DECLARE_CRYPTO_WAIT(wait); struct fscrypt_info *ci = inode->i_crypt_info; struct crypto_skcipher *tfm = ci->ci_ctfm; - int res = 0; - char iv[FS_CRYPTO_BLOCK_SIZE]; + union fscrypt_iv iv; 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; + int res; /* * 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); + fscrypt_generate_iv(&iv, 0, ci); /* Set up the encryption request */ req = skcipher_request_alloc(tfm, GFP_NOFS); - if (!req) { - printk_ratelimited(KERN_ERR - "%s: skcipher_request_alloc() failed\n", __func__); + if (!req) return -ENOMEM; - } 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 - "%s: Error (error code %d)\n", __func__, res); + fscrypt_err(inode, "Filename encryption failed: %d", res); return res; } - oname->len = cryptlen; return 0; } @@ -111,45 +90,32 @@ static int fname_decrypt(struct inode *inode, 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; - int res = 0; - char iv[FS_CRYPTO_BLOCK_SIZE]; - unsigned lim; - - lim = inode->i_sb->s_cop->max_namelen(inode); - if (iname->len <= 0 || iname->len > lim) - return -EIO; + union fscrypt_iv iv; + int res; /* Allocate request */ req = skcipher_request_alloc(tfm, GFP_NOFS); - if (!req) { - printk_ratelimited(KERN_ERR - "%s: crypto_request_alloc() failed\n", __func__); + if (!req) return -ENOMEM; - } 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); + fscrypt_generate_iv(&iv, 0, ci); /* Create decryption request */ 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; - } + skcipher_request_set_crypt(req, &src_sg, &dst_sg, iname->len, &iv); + res = crypto_wait_req(crypto_skcipher_decrypt(req), &wait); skcipher_request_free(req); if (res < 0) { - printk_ratelimited(KERN_ERR - "%s: Error (error code %d)\n", __func__, res); + fscrypt_err(inode, "Filename decryption failed: %d", res); return res; } @@ -157,44 +123,45 @@ static int fname_decrypt(struct inode *inode, return 0; } -static const char *lookup_table = +static const char lookup_table[65] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,"; #define BASE64_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3) /** - * digest_encode() - + * base64_encode() - * - * Encodes the input digest using characters from the set [a-zA-Z0-9_+]. + * Encodes the input string using characters from the set [A-Za-z0-9+,]. * The encoded string is roughly 4/3 times the size of the input string. + * + * Return: length of the encoded string */ -static int digest_encode(const char *src, int len, char *dst) +static int base64_encode(const u8 *src, int len, char *dst) { - int i = 0, bits = 0, ac = 0; + int i, bits = 0, ac = 0; char *cp = dst; - while (i < len) { - ac += (((unsigned char) src[i]) << bits); + for (i = 0; i < len; i++) { + ac += src[i] << bits; bits += 8; do { *cp++ = lookup_table[ac & 0x3f]; ac >>= 6; bits -= 6; } while (bits >= 6); - i++; } if (bits) *cp++ = lookup_table[ac & 0x3f]; return cp - dst; } -static int digest_decode(const char *src, int len, char *dst) +static int base64_decode(const char *src, int len, u8 *dst) { - int i = 0, bits = 0, ac = 0; + int i, bits = 0, ac = 0; const char *p; - char *cp = dst; + u8 *cp = dst; - while (i < len) { + for (i = 0; i < len; i++) { p = strchr(lookup_table, src[i]); if (p == NULL || src[i] == 0) return -2; @@ -205,57 +172,59 @@ static int digest_decode(const char *src, int len, char *dst) ac >>= 8; bits -= 8; } - i++; } if (ac) return -1; return cp - dst; } -u32 fscrypt_fname_encrypted_size(const 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; - - 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); + const struct fscrypt_info *ci = inode->i_crypt_info; + int padding = 4 << (fscrypt_policy_flags(&ci->ci_policy) & + FSCRYPT_POLICY_FLAGS_PAD_MASK); + u32 encrypted_len; + + 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(const struct inode *inode, - u32 ilen, struct fscrypt_str *crypto_str) + u32 max_encrypted_len, + struct fscrypt_str *crypto_str) { - 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))); + u32 max_presented_len; - crypto_str->len = olen; - olen = max(olen, max_encoded_len); + max_presented_len = max(max_encoded_len, max_encrypted_len); - /* - * Allocated buffer can hold one more character to null-terminate the - * string - */ - crypto_str->name = kmalloc(olen + 1, GFP_NOFS); - if (!(crypto_str->name)) + 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) { @@ -296,11 +265,11 @@ int fscrypt_fname_disk_to_usr(struct inode *inode, if (iname->len < FS_CRYPTO_BLOCK_SIZE) return -EUCLEAN; - if (inode->i_crypt_info) + if (fscrypt_has_encryption_key(inode)) return fname_decrypt(inode, iname, oname); if (iname->len <= FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE) { - oname->len = digest_encode(iname->name, iname->len, + oname->len = base64_encode(iname->name, iname->len, oname->name); return 0; } @@ -315,42 +284,13 @@ int fscrypt_fname_disk_to_usr(struct inode *inode, FSCRYPT_FNAME_DIGEST(iname->name, iname->len), FSCRYPT_FNAME_DIGEST_SIZE); oname->name[0] = '_'; - oname->len = 1 + digest_encode((const char *)&digested_name, + oname->len = 1 + base64_encode((const u8 *)&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 - * - * The caller must have allocated sufficient memory for the @oname string. - * - * 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); - -/** * 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 @@ -383,22 +323,27 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, 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; } ret = fscrypt_get_encryption_info(dir); - if (ret && ret != -EOPNOTSUPP) + if (ret) 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_has_encryption_key(dir)) { + if (!fscrypt_fname_encrypted_size(dir, iname->len, + dir->i_sb->s_cop->max_namelen, + &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; @@ -407,6 +352,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, } if (!lookup) return -ENOKEY; + fname->is_ciphertext_name = true; /* * We don't have the key and we are doing a lookup; decode the @@ -431,8 +377,8 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, if (fname->crypto_buf.name == NULL) return -ENOMEM; - ret = digest_decode(iname->name + digested, iname->len - digested, - fname->crypto_buf.name); + ret = base64_decode(iname->name + digested, iname->len - digested, + fname->crypto_buf.name); if (ret < 0) { ret = -ENOENT; goto errout; @@ -450,7 +396,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, return 0; errout: - fscrypt_fname_free_buffer(&fname->crypto_buf); + kfree(fname->crypto_buf.name); return ret; } EXPORT_SYMBOL(fscrypt_setup_filename); |