/* * algif_skcipher: User-space interface for skcipher algorithms * * This file provides the user-space API for symmetric key ciphers. * * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au> * * 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 <crypto/scatterwalk.h> #include <crypto/skcipher.h> #include <crypto/if_alg.h> #include <linux/init.h> #include <linux/list.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/module.h> #include <linux/net.h> #include <net/sock.h> struct skcipher_sg_list { struct list_head list; int cur; struct scatterlist sg[0]; }; struct skcipher_ctx { struct list_head tsgl; struct af_alg_sgl rsgl; void *iv; struct af_alg_completion completion; unsigned used; unsigned int len; bool more; bool merge; bool enc; struct ablkcipher_request req; }; #define MAX_SGL_ENTS ((4096 - sizeof(struct skcipher_sg_list)) / \ sizeof(struct scatterlist) - 1) static inline int skcipher_sndbuf(struct sock *sk) { struct alg_sock *ask = alg_sk(sk); struct skcipher_ctx *ctx = ask->private; return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) - ctx->used, 0); } static inline bool skcipher_writable(struct sock *sk) { return PAGE_SIZE <= skcipher_sndbuf(sk); } static int skcipher_alloc_sgl(struct sock *sk) { struct alg_sock *ask = alg_sk(sk); struct skcipher_ctx *ctx = ask->private; struct skcipher_sg_list *sgl; struct scatterlist *sg = NULL; sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list); if (!list_empty(&ctx->tsgl)) sg = sgl->sg; if (!sg || sgl->cur >= MAX_SGL_ENTS) { sgl = sock_kmalloc(sk, sizeof(*sgl) + sizeof(sgl->sg[0]) * (MAX_SGL_ENTS + 1), GFP_KERNEL); if (!sgl) return -ENOMEM; sg_init_table(sgl->sg, MAX_SGL_ENTS + 1); sgl->cur = 0; if (sg) scatterwalk_sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg); list_add_tail(&sgl->list, &ctx->tsgl); } return 0; } static void skcipher_pull_sgl(struct sock *sk, int used) { struct alg_sock *ask = alg_sk(sk); struct skcipher_ctx *ctx = ask->private; struct skcipher_sg_list *sgl; struct scatterlist *sg; int i; while (!list_empty(&ctx->tsgl)) { sgl = list_first_entry(&ctx->tsgl, struct skcipher_sg_list, list); sg = sgl->sg; for (i = 0; i < sgl->cur; i++) { int plen = min_t(int, used, sg[i].length); if (!sg_page(sg + i)) continue; sg[i].length -= plen; sg[i].offset += plen; used -= plen; ctx->used -= plen; if (sg[i].length) return; put_page(sg_page(sg + i)); sg_assign_page(sg + i, NULL); } list_del(&sgl->list); sock_kfree_s(sk, sgl, sizeof(*sgl) + sizeof(sgl->sg[0]) * (MAX_SGL_ENTS + 1)); } if (!ctx->used) ctx->merge = 0; } static void skcipher_free_sgl(struct sock *sk) { struct alg_sock *ask = alg_sk(sk); struct skcipher_ctx *ctx = ask->private; skcipher_pull_sgl(sk, ctx->used); } static int skcipher_wait_for_wmem(struct sock *sk, unsigned flags) { long timeout; DEFINE_WAIT(wait); int err = -ERESTARTSYS; if (flags & MSG_DONTWAIT) return -EAGAIN; set_bit(SOCK_ASYNC_NOSPACE, &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, skcipher_writable(sk))) { err = 0; break; } } finish_wait(sk_sleep(sk), &wait); return err; } static void skcipher_wmem_wakeup(struct sock *sk) { struct socket_wq *wq; if (!skcipher_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 skcipher_wait_for_data(struct sock *sk, unsigned flags) { struct alg_sock *ask = alg_sk(sk); struct skcipher_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->used)) { err = 0; break; } } finish_wait(sk_sleep(sk), &wait); clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); return err; } static void skcipher_data_wakeup(struct sock *sk) { struct alg_sock *ask = alg_sk(sk); struct skcipher_ctx *ctx = ask->private; struct socket_wq *wq; 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 skcipher_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 skcipher_ctx *ctx = ask->private; struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req); unsigned ivsize = crypto_ablkcipher_ivsize(tfm); struct skcipher_sg_list *sgl; struct af_alg_control con = {}; long copied = 0; bool enc = 0; bool init = 0; int err; int i; 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; } err = -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); } while (size) { struct scatterlist *sg; unsigned long len = size; int plen; if (ctx->merge) { sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list); 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 (!skcipher_writable(sk)) { err = skcipher_wait_for_wmem(sk, msg->msg_flags); if (err) goto unlock; } len = min_t(unsigned long, len, skcipher_sndbuf(sk)); err = skcipher_alloc_sgl(sk); if (err) goto unlock; sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list); sg = sgl->sg; do { i = sgl->cur; plen = min_t(int, len, PAGE_SIZE); sg_assign_page(sg + i, alloc_page(GFP_KERNEL)); err = -ENOMEM; if (!sg_page(sg + i)) goto unlock; err = memcpy_from_msg(page_address(sg_page(sg + i)), msg, plen); if (err) { __free_page(sg_page(sg + i)); sg_assign_page(sg + i, NULL); goto unlock; } sg[i].length = plen; len -= plen; ctx->used += plen; copied += plen; size -= plen; sgl->cur++; } while (len && sgl->cur < MAX_SGL_ENTS); ctx->merge = plen & (PAGE_SIZE - 1); } err = 0; ctx->more = msg->msg_flags & MSG_MORE; unlock: skcipher_data_wakeup(sk); release_sock(sk); return copied ?: err; } static ssize_t skcipher_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 skcipher_ctx *ctx = ask->private; struct skcipher_sg_list *sgl; int err = -EINVAL; if (flags & MSG_SENDPAGE_NOTLAST) flags |= MSG_MORE; lock_sock(sk); if (!ctx->more && ctx->used) goto unlock; if (!size) goto done; if (!skcipher_writable(sk)) { err = skcipher_wait_for_wmem(sk, flags); if (err) goto unlock; } err = skcipher_alloc_sgl(sk); if (err) goto unlock; ctx->merge = 0; sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list); get_page(page); sg_set_page(sgl->sg + sgl->cur, page, size, offset); sgl->cur++; ctx->used += size; done: ctx->more = flags & MSG_MORE; unlock: skcipher_data_wakeup(sk); release_sock(sk); return err ?: size; } static int skcipher_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 skcipher_ctx *ctx = ask->private; unsigned bs = crypto_ablkcipher_blocksize(crypto_ablkcipher_reqtfm( &ctx->req)); struct skcipher_sg_list *sgl; struct scatterlist *sg; unsigned long iovlen; const struct iovec *iov; int err = -EAGAIN; int used; long copied = 0; lock_sock(sk); for (iov = msg->msg_iter.iov, iovlen = msg->msg_iter.nr_segs; iovlen > 0; iovlen--, iov++) { unsigned long seglen = iov->iov_len; char __user *from = iov->iov_base; while (seglen) { sgl = list_first_entry(&ctx->tsgl, struct skcipher_sg_list, list); sg = sgl->sg; while (!sg->length) sg++; if (!ctx->used) { err = skcipher_wait_for_data(sk, flags); if (err) goto unlock; } used = min_t(unsigned long, ctx->used, seglen); used = af_alg_make_sg(&ctx->rsgl, from, used, 1); err = used; if (err < 0) goto unlock; if (ctx->more || used < ctx->used) used -= used % bs; err = -EINVAL; if (!used) goto free; ablkcipher_request_set_crypt(&ctx->req, sg, ctx->rsgl.sg, used, ctx->iv); err = af_alg_wait_for_completion( ctx->enc ? crypto_ablkcipher_encrypt(&ctx->req) : crypto_ablkcipher_decrypt(&ctx->req), &ctx->completion); free: af_alg_free_sg(&ctx->rsgl); if (err) goto unlock; copied += used; from += used; seglen -= used; skcipher_pull_sgl(sk, used); } } err = 0; unlock: skcipher_wmem_wakeup(sk); release_sock(sk); return copied ?: err; } static unsigned int skcipher_poll(struct file *file, struct socket *sock, poll_table *wait) { struct sock *sk = sock->sk; struct alg_sock *ask = alg_sk(sk); struct skcipher_ctx *ctx = ask->private; unsigned int mask; sock_poll_wait(file, sk_sleep(sk), wait); mask = 0; if (ctx->used) mask |= POLLIN | POLLRDNORM; if (skcipher_writable(sk)) mask |= POLLOUT | POLLWRNORM | POLLWRBAND; return mask; } static struct proto_ops algif_skcipher_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 = skcipher_sendmsg, .sendpage = skcipher_sendpage, .recvmsg = skcipher_recvmsg, .poll = skcipher_poll, }; static void *skcipher_bind(const char *name, u32 type, u32 mask) { return crypto_alloc_ablkcipher(name, type, mask); } static void skcipher_release(void *private) { crypto_free_ablkcipher(private); } static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen) { return crypto_ablkcipher_setkey(private, key, keylen); } static void skcipher_sock_destruct(struct sock *sk) { struct alg_sock *ask = alg_sk(sk); struct skcipher_ctx *ctx = ask->private; struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req); skcipher_free_sgl(sk); sock_kzfree_s(sk, ctx->iv, crypto_ablkcipher_ivsize(tfm)); sock_kfree_s(sk, ctx, ctx->len); af_alg_release_parent(sk); } static int skcipher_accept_parent(void *private, struct sock *sk) { struct skcipher_ctx *ctx; struct alg_sock *ask = alg_sk(sk); unsigned int len = sizeof(*ctx) + crypto_ablkcipher_reqsize(private); ctx = sock_kmalloc(sk, len, GFP_KERNEL); if (!ctx) return -ENOMEM; ctx->iv = sock_kmalloc(sk, crypto_ablkcipher_ivsize(private), GFP_KERNEL); if (!ctx->iv) { sock_kfree_s(sk, ctx, len); return -ENOMEM; } memset(ctx->iv, 0, crypto_ablkcipher_ivsize(private)); INIT_LIST_HEAD(&ctx->tsgl); ctx->len = len; ctx->used = 0; ctx->more = 0; ctx->merge = 0; ctx->enc = 0; af_alg_init_completion(&ctx->completion); ask->private = ctx; ablkcipher_request_set_tfm(&ctx->req, private); ablkcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG, af_alg_complete, &ctx->completion); sk->sk_destruct = skcipher_sock_destruct; return 0; } static const struct af_alg_type algif_type_skcipher = { .bind = skcipher_bind, .release = skcipher_release, .setkey = skcipher_setkey, .accept = skcipher_accept_parent, .ops = &algif_skcipher_ops, .name = "skcipher", .owner = THIS_MODULE }; static int __init algif_skcipher_init(void) { return af_alg_register_type(&algif_type_skcipher); } static void __exit algif_skcipher_exit(void) { int err = af_alg_unregister_type(&algif_type_skcipher); BUG_ON(err); } module_init(algif_skcipher_init); module_exit(algif_skcipher_exit); MODULE_LICENSE("GPL");