diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c new file mode 100644 index 000000000000..527d27b023ab --- /dev/null +++ b/crypto/algif_aead.c @@ -0,0 +1,666 @@ +/* + * algif_aead: User-space interface for AEAD algorithms + * + * Copyright (C) 2014, Stephan Mueller + * + * This file provides the user-space API for AEAD ciphers. + * + * This file is derived from algif_skcipher.c. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct aead_sg_list { + unsigned int cur; + struct scatterlist sg[ALG_MAX_PAGES]; +}; + +struct aead_ctx { + struct aead_sg_list tsgl; + /* + * RSGL_MAX_ENTRIES is an artificial limit where user space at maximum + * can cause the kernel to allocate RSGL_MAX_ENTRIES * ALG_MAX_PAGES + * bytes + */ +#define RSGL_MAX_ENTRIES ALG_MAX_PAGES + struct af_alg_sgl rsgl[RSGL_MAX_ENTRIES]; + + void *iv; + + struct af_alg_completion completion; + + unsigned long used; + + unsigned int len; + bool more; + bool merge; + bool enc; + + size_t aead_assoclen; + struct aead_request aead_req; +}; + +static inline int aead_sndbuf(struct sock *sk) +{ + struct alg_sock *ask = alg_sk(sk); + struct aead_ctx *ctx = ask->private; + + return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) - + ctx->used, 0); +} + +static inline bool aead_writable(struct sock *sk) +{ + return PAGE_SIZE <= aead_sndbuf(sk); +} + +static inline bool aead_sufficient_data(struct aead_ctx *ctx) +{ + unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req)); + + return (ctx->used >= (ctx->aead_assoclen + (ctx->enc ? 0 : as))); +} + +static void aead_put_sgl(struct sock *sk) +{ + struct alg_sock *ask = alg_sk(sk); + struct aead_ctx *ctx = ask->private; + struct aead_sg_list *sgl = &ctx->tsgl; + struct scatterlist *sg = sgl->sg; + unsigned int i; + + for (i = 0; i < sgl->cur; i++) { + if (!sg_page(sg + i)) + continue; + + put_page(sg_page(sg + i)); + sg_assign_page(sg + i, NULL); + } + sgl->cur = 0; + ctx->used = 0; + ctx->more = 0; + ctx->merge = 0; +} + +static void aead_wmem_wakeup(struct sock *sk) +{ + struct socket_wq *wq; + + if (!aead_writable(sk)) + return; + + rcu_read_lock(); + wq = rcu_dereference(sk->sk_wq); + if (wq_has_sleeper(wq)) + wake_up_interruptible_sync_poll(&wq->wait, POLLIN | + POLLRDNORM | + POLLRDBAND); + sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN); + rcu_read_unlock(); +} + +static int aead_wait_for_data(struct sock *sk, unsigned flags) +{ + struct alg_sock *ask = alg_sk(sk); + struct aead_ctx *ctx = ask->private; + long timeout; + DEFINE_WAIT(wait); + int err = -ERESTARTSYS; + + if (flags & MSG_DONTWAIT) + return -EAGAIN; + + set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); + + for (;;) { + if (signal_pending(current)) + break; + prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); + timeout = MAX_SCHEDULE_TIMEOUT; + if (sk_wait_event(sk, &timeout, !ctx->more)) { + err = 0; + break; + } + } + finish_wait(sk_sleep(sk), &wait); + + clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); + + return err; +} + +static void aead_data_wakeup(struct sock *sk) +{ + struct alg_sock *ask = alg_sk(sk); + struct aead_ctx *ctx = ask->private; + struct socket_wq *wq; + + if (ctx->more) + return; + if (!ctx->used) + return; + + rcu_read_lock(); + wq = rcu_dereference(sk->sk_wq); + if (wq_has_sleeper(wq)) + wake_up_interruptible_sync_poll(&wq->wait, POLLOUT | + POLLRDNORM | + POLLRDBAND); + sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT); + rcu_read_unlock(); +} + +static int aead_sendmsg(struct kiocb *unused, struct socket *sock, + struct msghdr *msg, size_t size) +{ + struct sock *sk = sock->sk; + struct alg_sock *ask = alg_sk(sk); + struct aead_ctx *ctx = ask->private; + unsigned ivsize = + crypto_aead_ivsize(crypto_aead_reqtfm(&ctx->aead_req)); + struct aead_sg_list *sgl = &ctx->tsgl; + struct af_alg_control con = {}; + long copied = 0; + bool enc = 0; + bool init = 0; + int err = -EINVAL; + + if (msg->msg_controllen) { + err = af_alg_cmsg_send(msg, &con); + if (err) + return err; + + init = 1; + switch (con.op) { + case ALG_OP_ENCRYPT: + enc = 1; + break; + case ALG_OP_DECRYPT: + enc = 0; + break; + default: + return -EINVAL; + } + + if (con.iv && con.iv->ivlen != ivsize) + return -EINVAL; + } + + lock_sock(sk); + if (!ctx->more && ctx->used) + goto unlock; + + if (init) { + ctx->enc = enc; + if (con.iv) + memcpy(ctx->iv, con.iv->iv, ivsize); + + ctx->aead_assoclen = con.aead_assoclen; + } + + while (size) { + unsigned long len = size; + struct scatterlist *sg = NULL; + + /* use the existing memory in an allocated page */ + if (ctx->merge) { + sg = sgl->sg + sgl->cur - 1; + len = min_t(unsigned long, len, + PAGE_SIZE - sg->offset - sg->length); + err = memcpy_from_msg(page_address(sg_page(sg)) + + sg->offset + sg->length, + msg, len); + if (err) + goto unlock; + + sg->length += len; + ctx->merge = (sg->offset + sg->length) & + (PAGE_SIZE - 1); + + ctx->used += len; + copied += len; + size -= len; + continue; + } + + if (!aead_writable(sk)) { + /* user space sent too much data */ + aead_put_sgl(sk); + err = -EMSGSIZE; + goto unlock; + } + + /* allocate a new page */ + len = min_t(unsigned long, size, aead_sndbuf(sk)); + while (len) { + int plen = 0; + + if (sgl->cur >= ALG_MAX_PAGES) { + aead_put_sgl(sk); + err = -E2BIG; + goto unlock; + } + + sg = sgl->sg + sgl->cur; + plen = min_t(int, len, PAGE_SIZE); + + sg_assign_page(sg, alloc_page(GFP_KERNEL)); + err = -ENOMEM; + if (!sg_page(sg)) + goto unlock; + + err = memcpy_from_msg(page_address(sg_page(sg)), + msg, plen); + if (err) { + __free_page(sg_page(sg)); + sg_assign_page(sg, NULL); + goto unlock; + } + + sg->offset = 0; + sg->length = plen; + len -= plen; + ctx->used += plen; + copied += plen; + sgl->cur++; + size -= plen; + ctx->merge = plen & (PAGE_SIZE - 1); + } + } + + err = 0; + + ctx->more = msg->msg_flags & MSG_MORE; + if (!ctx->more && !aead_sufficient_data(ctx)) { + aead_put_sgl(sk); + err = -EMSGSIZE; + } + +unlock: + aead_data_wakeup(sk); + release_sock(sk); + + return err ?: copied; +} + +static ssize_t aead_sendpage(struct socket *sock, struct page *page, + int offset, size_t size, int flags) +{ + struct sock *sk = sock->sk; + struct alg_sock *ask = alg_sk(sk); + struct aead_ctx *ctx = ask->private; + struct aead_sg_list *sgl = &ctx->tsgl; + int err = -EINVAL; + + if (flags & MSG_SENDPAGE_NOTLAST) + flags |= MSG_MORE; + + if (sgl->cur >= ALG_MAX_PAGES) + return -E2BIG; + + lock_sock(sk); + if (!ctx->more && ctx->used) + goto unlock; + + if (!size) + goto done; + + if (!aead_writable(sk)) { + /* user space sent too much data */ + aead_put_sgl(sk); + err = -EMSGSIZE; + goto unlock; + } + + ctx->merge = 0; + + get_page(page); + sg_set_page(sgl->sg + sgl->cur, page, size, offset); + sgl->cur++; + ctx->used += size; + + err = 0; + +done: + ctx->more = flags & MSG_MORE; + if (!ctx->more && !aead_sufficient_data(ctx)) { + aead_put_sgl(sk); + err = -EMSGSIZE; + } + +unlock: + aead_data_wakeup(sk); + release_sock(sk); + + return err ?: size; +} + +static int aead_recvmsg(struct kiocb *unused, struct socket *sock, + struct msghdr *msg, size_t ignored, int flags) +{ + struct sock *sk = sock->sk; + struct alg_sock *ask = alg_sk(sk); + struct aead_ctx *ctx = ask->private; + unsigned bs = crypto_aead_blocksize(crypto_aead_reqtfm(&ctx->aead_req)); + unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req)); + struct aead_sg_list *sgl = &ctx->tsgl; + struct scatterlist *sg = NULL; + struct scatterlist assoc[ALG_MAX_PAGES]; + size_t assoclen = 0; + unsigned int i = 0; + int err = -EINVAL; + unsigned long used = 0; + size_t outlen = 0; + size_t usedpages = 0; + unsigned int cnt = 0; + + /* Limit number of IOV blocks to be accessed below */ + if (msg->msg_iter.nr_segs > RSGL_MAX_ENTRIES) + return -ENOMSG; + + lock_sock(sk); + + /* + * AEAD memory structure: For encryption, the tag is appended to the + * ciphertext which implies that the memory allocated for the ciphertext + * must be increased by the tag length. For decryption, the tag + * is expected to be concatenated to the ciphertext. The plaintext + * therefore has a memory size of the ciphertext minus the tag length. + * + * The memory structure for cipher operation has the following + * structure: + * AEAD encryption input: assoc data || plaintext + * AEAD encryption output: cipherntext || auth tag + * AEAD decryption input: assoc data || ciphertext || auth tag + * AEAD decryption output: plaintext + */ + + if (ctx->more) { + err = aead_wait_for_data(sk, flags); + if (err) + goto unlock; + } + + used = ctx->used; + + /* + * Make sure sufficient data is present -- note, the same check is + * is also present in sendmsg/sendpage. The checks in sendpage/sendmsg + * shall provide an information to the data sender that something is + * wrong, but they are irrelevant to maintain the kernel integrity. + * We need this check here too in case user space decides to not honor + * the error message in sendmsg/sendpage and still call recvmsg. This + * check here protects the kernel integrity. + */ + if (!aead_sufficient_data(ctx)) + goto unlock; + + /* + * The cipher operation input data is reduced by the associated data + * length as this data is processed separately later on. + */ + used -= ctx->aead_assoclen; + + if (ctx->enc) { + /* round up output buffer to multiple of block size */ + outlen = ((used + bs - 1) / bs * bs); + /* add the size needed for the auth tag to be created */ + outlen += as; + } else { + /* output data size is input without the authentication tag */ + outlen = used - as; + /* round up output buffer to multiple of block size */ + outlen = ((outlen + bs - 1) / bs * bs); + } + + /* convert iovecs of output buffers into scatterlists */ + while (iov_iter_count(&msg->msg_iter)) { + size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter), + (outlen - usedpages)); + + /* make one iovec available as scatterlist */ + err = af_alg_make_sg(&ctx->rsgl[cnt], &msg->msg_iter, + seglen); + if (err < 0) + goto unlock; + usedpages += err; + /* chain the new scatterlist with initial list */ + if (cnt) + scatterwalk_crypto_chain(ctx->rsgl[0].sg, + ctx->rsgl[cnt].sg, 1, + sg_nents(ctx->rsgl[cnt-1].sg)); + /* we do not need more iovecs as we have sufficient memory */ + if (outlen <= usedpages) + break; + iov_iter_advance(&msg->msg_iter, err); + cnt++; + } + + err = -EINVAL; + /* ensure output buffer is sufficiently large */ + if (usedpages < outlen) + goto unlock; + + sg_init_table(assoc, ALG_MAX_PAGES); + assoclen = ctx->aead_assoclen; + /* + * Split scatterlist into two: first part becomes AD, second part + * is plaintext / ciphertext. The first part is assigned to assoc + * scatterlist. When this loop finishes, sg points to the start of the + * plaintext / ciphertext. + */ + for (i = 0; i < ctx->tsgl.cur; i++) { + sg = sgl->sg + i; + if (sg->length <= assoclen) { + /* AD is larger than one page */ + sg_set_page(assoc + i, sg_page(sg), + sg->length, sg->offset); + assoclen -= sg->length; + if (i >= ctx->tsgl.cur) + goto unlock; + } else if (!assoclen) { + /* current page is to start of plaintext / ciphertext */ + if (i) + /* AD terminates at page boundary */ + sg_mark_end(assoc + i - 1); + else + /* AD size is zero */ + sg_mark_end(assoc); + break; + } else { + /* AD does not terminate at page boundary */ + sg_set_page(assoc + i, sg_page(sg), + assoclen, sg->offset); + sg_mark_end(assoc + i); + /* plaintext / ciphertext starts after AD */ + sg->length -= assoclen; + sg->offset += assoclen; + break; + } + } + + aead_request_set_assoc(&ctx->aead_req, assoc, ctx->aead_assoclen); + aead_request_set_crypt(&ctx->aead_req, sg, ctx->rsgl[0].sg, used, + ctx->iv); + + err = af_alg_wait_for_completion(ctx->enc ? + crypto_aead_encrypt(&ctx->aead_req) : + crypto_aead_decrypt(&ctx->aead_req), + &ctx->completion); + + if (err) { + /* EBADMSG implies a valid cipher operation took place */ + if (err == -EBADMSG) + aead_put_sgl(sk); + goto unlock; + } + + aead_put_sgl(sk); + + err = 0; + +unlock: + for (i = 0; i < cnt; i++) + af_alg_free_sg(&ctx->rsgl[i]); + + aead_wmem_wakeup(sk); + release_sock(sk); + + return err ? err : outlen; +} + +static unsigned int aead_poll(struct file *file, struct socket *sock, + poll_table *wait) +{ + struct sock *sk = sock->sk; + struct alg_sock *ask = alg_sk(sk); + struct aead_ctx *ctx = ask->private; + unsigned int mask; + + sock_poll_wait(file, sk_sleep(sk), wait); + mask = 0; + + if (!ctx->more) + mask |= POLLIN | POLLRDNORM; + + if (aead_writable(sk)) + mask |= POLLOUT | POLLWRNORM | POLLWRBAND; + + return mask; +} + +static struct proto_ops algif_aead_ops = { + .family = PF_ALG, + + .connect = sock_no_connect, + .socketpair = sock_no_socketpair, + .getname = sock_no_getname, + .ioctl = sock_no_ioctl, + .listen = sock_no_listen, + .shutdown = sock_no_shutdown, + .getsockopt = sock_no_getsockopt, + .mmap = sock_no_mmap, + .bind = sock_no_bind, + .accept = sock_no_accept, + .setsockopt = sock_no_setsockopt, + + .release = af_alg_release, + .sendmsg = aead_sendmsg, + .sendpage = aead_sendpage, + .recvmsg = aead_recvmsg, + .poll = aead_poll, +}; + +static void *aead_bind(const char *name, u32 type, u32 mask) +{ + return crypto_alloc_aead(name, type, mask); +} + +static void aead_release(void *private) +{ + crypto_free_aead(private); +} + +static int aead_setauthsize(void *private, unsigned int authsize) +{ + return crypto_aead_setauthsize(private, authsize); +} + +static int aead_setkey(void *private, const u8 *key, unsigned int keylen) +{ + return crypto_aead_setkey(private, key, keylen); +} + +static void aead_sock_destruct(struct sock *sk) +{ + struct alg_sock *ask = alg_sk(sk); + struct aead_ctx *ctx = ask->private; + unsigned int ivlen = crypto_aead_ivsize( + crypto_aead_reqtfm(&ctx->aead_req)); + + aead_put_sgl(sk); + sock_kzfree_s(sk, ctx->iv, ivlen); + sock_kfree_s(sk, ctx, ctx->len); + af_alg_release_parent(sk); +} + +static int aead_accept_parent(void *private, struct sock *sk) +{ + struct aead_ctx *ctx; + struct alg_sock *ask = alg_sk(sk); + unsigned int len = sizeof(*ctx) + crypto_aead_reqsize(private); + unsigned int ivlen = crypto_aead_ivsize(private); + + ctx = sock_kmalloc(sk, len, GFP_KERNEL); + if (!ctx) + return -ENOMEM; + memset(ctx, 0, len); + + ctx->iv = sock_kmalloc(sk, ivlen, GFP_KERNEL); + if (!ctx->iv) { + sock_kfree_s(sk, ctx, len); + return -ENOMEM; + } + memset(ctx->iv, 0, ivlen); + + ctx->len = len; + ctx->used = 0; + ctx->more = 0; + ctx->merge = 0; + ctx->enc = 0; + ctx->tsgl.cur = 0; + ctx->aead_assoclen = 0; + af_alg_init_completion(&ctx->completion); + sg_init_table(ctx->tsgl.sg, ALG_MAX_PAGES); + + ask->private = ctx; + + aead_request_set_tfm(&ctx->aead_req, private); + aead_request_set_callback(&ctx->aead_req, CRYPTO_TFM_REQ_MAY_BACKLOG, + af_alg_complete, &ctx->completion); + + sk->sk_destruct = aead_sock_destruct; + + return 0; +} + +static const struct af_alg_type algif_type_aead = { + .bind = aead_bind, + .release = aead_release, + .setkey = aead_setkey, + .setauthsize = aead_setauthsize, + .accept = aead_accept_parent, + .ops = &algif_aead_ops, + .name = "aead", + .owner = THIS_MODULE +}; + +static int __init algif_aead_init(void) +{ + return af_alg_register_type(&algif_type_aead); +} + +static void __exit algif_aead_exit(void) +{ + int err = af_alg_unregister_type(&algif_type_aead); + BUG_ON(err); +} + +module_init(algif_aead_init); +module_exit(algif_aead_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Stephan Mueller "); +MODULE_DESCRIPTION("AEAD kernel crypto API user space interface");