--- /dev/null
+/*
+ * Driver for /dev/crypto device (aka CryptoDev)
+ *
+ * Copyright (c) 2004 Michal Ludvig <mludvig@suse.cz>, SuSE Labs
+ *
+ * Device /dev/crypto provides an interface for
+ * accessing kernel CryptoAPI algorithms (ciphers,
+ * hashes) from userspace programs.
+ *
+ * /dev/crypto interface was originally introduced in
+ * OpenBSD and this module attempts to keep the API,
+ * although a bit extended.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/miscdevice.h>
+#include <linux/crypto.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/random.h>
+#include <linux/cryptodev.h>
+#include <asm/uaccess.h>
+#include <asm/ioctl.h>
+#include <linux/scatterlist.h>
+
+MODULE_AUTHOR("Michal Ludvig <mludvig@suse.cz>");
+MODULE_DESCRIPTION("CryptoDev driver");
+MODULE_LICENSE("Dual BSD/GPL");
+
+/* ====== Compile-time config ====== */
+
+#define CRYPTODEV_STATS
+
+/* ====== Module parameters ====== */
+
+static int verbosity = 0;
+module_param(verbosity, int, 0644);
+MODULE_PARM_DESC(verbosity, "0: normal, 1: verbose, 2: debug");
+
+#ifdef CRYPTODEV_STATS
+static int enable_stats = 0;
+module_param(enable_stats, int, 0644);
+MODULE_PARM_DESC(enable_stats, "collect statictics about cryptodev usage");
+#endif
+
+/* ====== Debug helpers ====== */
+
+#define PFX "cryptodev: "
+#define dprintk(level,severity,format,a...) \
+ do { \
+ if (level <= verbosity) \
+ printk(severity PFX "%s[%u]: " format, \
+ current->comm, current->pid, \
+ ##a); \
+ } while (0)
+
+/* ====== CryptoAPI ====== */
+
+struct csession {
+ struct list_head entry;
+ struct semaphore sem;
+ struct crypto_blkcipher *tfm;
+ uint32_t sid;
+#ifdef CRYPTODEV_STATS
+#if ! ((COP_ENCRYPT < 2) && (COP_DECRYPT < 2))
+#error Struct csession.stat uses COP_{ENCRYPT,DECRYPT} as indices. Do something!
+#endif
+ unsigned long long stat[2];
+ size_t stat_max_size, stat_count;
+#endif
+};
+
+struct fcrypt {
+ struct list_head list;
+ struct semaphore sem;
+};
+
+/* Prepare session for future use. */
+static int
+crypto_create_session(struct fcrypt *fcr, struct session_op *sop)
+{
+ struct csession *ses_new, *ses_ptr;
+ struct crypto_blkcipher *tfm;
+ int ret = 0;
+ char alg_name[MAX_ALG_NAME_LEN+1];
+ char alg_full_name[MAX_ALG_NAME_LEN+1];
+ const char *mode;
+ u8 *keyp;
+
+ /* Does the request make sense? */
+ if (!sop->cipher == !sop->mac) {
+ dprintk(1, KERN_DEBUG, "Both 'cipher' and 'mac' set or unset.\n");
+ return -EINVAL;
+ }
+
+ /* Copy-in the algorithm name if necessary. */
+ if (!sop->alg_namelen) {
+ /* Hmm, compatibility with OpenBSD CRYPTO_* constants...
+ Should we support it? */
+ dprintk(2, KERN_DEBUG, "OpenBSD constants are not (yet?) supported.\n");
+ return -EINVAL;
+ }
+
+ if(sop->alg_namelen > MAX_ALG_NAME_LEN) {
+ dprintk(1, KERN_DEBUG, "Algorithm name too long (%zu > %u)\n",
+ sop->alg_namelen, MAX_ALG_NAME_LEN);
+ return -EINVAL;
+ }
+
+ copy_from_user(alg_name, sop->alg_name, sop->alg_namelen);
+ alg_name[sop->alg_namelen] = '\0';
+
+ if(!sop->cipher) {
+ dprintk(2, KERN_DEBUG, "Hashes are not yet supported.\n");
+ return -EINVAL;
+ }
+
+ switch (sop->cipher & CRYPTO_FLAG_MASK) {
+ case CRYPTO_FLAG_ECB: mode = "ebc"; break;
+ case CRYPTO_FLAG_CBC: mode = "cbc"; break;
+ case CRYPTO_FLAG_CFB: mode = "cfb"; break;
+ case CRYPTO_FLAG_CTR: mode = "ctr"; break;
+#if 0
+ /* These modes are not yet supported. */
+ case CRYPTO_FLAG_OFB: mode = "ofb"; break;
+#endif
+ default: return -EINVAL;
+ }
+ snprintf(alg_full_name, sizeof(alg_full_name) - 1, "%s(%s)", mode, alg_name);
+
+ /* Set-up crypto transform. */
+ tfm = crypto_alloc_blkcipher(alg_full_name, 0, 0);
+ if (!tfm) {
+ dprintk(1, KERN_DEBUG, "Failed to load transform for %s %s\n",
+ alg_name, mode);
+ return -EINVAL;
+ }
+
+#if 0
+ /* Was correct key length supplied? */
+ if ((sop->keylen < crypto_tfm_alg_min_keysize(tfm)) ||
+ (sop->keylen > crypto_tfm_alg_max_keysize(tfm))) {
+ dprintk(1, KERN_DEBUG,
+ "Wrong keylen '%zu' for algorithm '%s'. Use %u to %u.\n",
+ sop->keylen, alg_name, crypto_tfm_alg_min_keysize(tfm),
+ crypto_tfm_alg_max_keysize(tfm));
+ crypto_free_blkcipher(tfm);
+ return -EINVAL;
+ }
+#endif
+
+ /* Copy the key from user and set to TFM. */
+ keyp = kmalloc(sop->keylen, GFP_KERNEL);
+ if (keyp == NULL) {
+ dprintk(1, KERN_ERR,
+ "Unable to allocate key buffer.\n");
+ crypto_free_blkcipher(tfm);
+ return -ENOMEM;
+ }
+ copy_from_user(keyp, sop->key, sop->keylen);
+ ret = crypto_blkcipher_setkey(tfm, keyp, sop->keylen);
+ kfree(keyp);
+ if (ret) {
+ dprintk(2, KERN_DEBUG,
+ "Setting key failed for %s-%zu-%s: flags=0x%X\n",
+ alg_name, sop->keylen*8, mode, crypto_blkcipher_tfm(tfm)->crt_flags);
+ dprintk(2, KERN_DEBUG,
+ "(see CRYPTO_TFM_RES_* in <linux/crypto.h> for details)\n");
+ crypto_free_blkcipher(tfm);
+ return -EINVAL;
+ }
+
+ /* Create a session and put it to the list. */
+ ses_new = kmalloc(sizeof(*ses_new), GFP_KERNEL);
+ if(!ses_new)
+ return -ENOMEM;
+
+ memset(ses_new, 0, sizeof(*ses_new));
+ get_random_bytes(&ses_new->sid, sizeof(ses_new->sid));
+ ses_new->tfm = tfm;
+ sema_init(&ses_new->sem, 1);
+
+ down(&fcr->sem);
+restart:
+ list_for_each_entry(ses_ptr, &fcr->list, entry) {
+ /* Check for duplicate SID */
+ if (unlikely(ses_new->sid == ses_ptr->sid)) {
+ get_random_bytes(&ses_new->sid, sizeof(ses_new->sid));
+ /* Unless we have a broken RNG this
+ shouldn't loop forever... ;-) */
+ goto restart;
+ }
+ }
+
+ list_add(&ses_new->entry, &fcr->list);
+ up(&fcr->sem);
+
+ dprintk(2, KERN_DEBUG, "Added session 0x%08X (%s-%zu-%s)\n",
+ ses_new->sid, alg_name, sop->keylen*8, mode);
+
+ /* Fill in some values for the user. */
+ sop->ses = ses_new->sid;
+ sop->blocksize = crypto_blkcipher_blocksize(tfm);
+
+ return 0;
+}
+
+/* Everything that needs to be done when remowing a session. */
+static inline void
+crypto_destroy_session(struct csession *ses_ptr)
+{
+ if(down_trylock(&ses_ptr->sem)) {
+ dprintk(2, KERN_DEBUG, "Waiting for semaphore of sid=0x%08X\n",
+ ses_ptr->sid);
+ down(&ses_ptr->sem);
+ }
+ dprintk(2, KERN_DEBUG, "Removed session 0x%08X\n", ses_ptr->sid);
+#if defined(CRYPTODEV_STATS)
+ if(enable_stats)
+ dprintk(2, KERN_DEBUG,
+ "Usage in Bytes: enc=%llu, dec=%llu, max=%zu, avg=%lu, cnt=%zu\n",
+ ses_ptr->stat[COP_ENCRYPT], ses_ptr->stat[COP_DECRYPT],
+ ses_ptr->stat_max_size, ses_ptr->stat_count > 0
+ ? ((unsigned long)(ses_ptr->stat[COP_ENCRYPT]+
+ ses_ptr->stat[COP_DECRYPT]) /
+ ses_ptr->stat_count) : 0,
+ ses_ptr->stat_count);
+#endif
+ crypto_free_blkcipher(ses_ptr->tfm);
+ ses_ptr->tfm = NULL;
+ up(&ses_ptr->sem);
+ kfree(ses_ptr);
+}
+
+/* Look up a session by ID and remove. */
+static int
+crypto_finish_session(struct fcrypt *fcr, uint32_t sid)
+{
+ struct csession *tmp, *ses_ptr;
+ struct list_head *head;
+ int ret = 0;
+
+ down(&fcr->sem);
+ head = &fcr->list;
+ list_for_each_entry_safe(ses_ptr, tmp, head, entry) {
+ if(ses_ptr->sid == sid) {
+ list_del(&ses_ptr->entry);
+ crypto_destroy_session(ses_ptr);
+ break;
+ }
+ }
+
+ if (!ses_ptr) {
+ dprintk(1, KERN_ERR, "Session with sid=0x%08X not found!\n", sid);
+ ret = -ENOENT;
+ }
+ up(&fcr->sem);
+
+ return ret;
+}
+
+/* Remove all sessions when closing the file */
+static int
+crypto_finish_all_sessions(struct fcrypt *fcr)
+{
+ struct csession *tmp, *ses_ptr;
+
+ down(&fcr->sem);
+ list_for_each_entry_safe(ses_ptr, tmp, &fcr->list, entry) {
+ list_del(&ses_ptr->entry);
+ crypto_destroy_session(ses_ptr);
+ }
+ up(&fcr->sem);
+
+ return 0;
+}
+
+/* Look up session by session ID. The returned session is locked. */
+static struct csession *
+crypto_get_session_by_sid(struct fcrypt *fcr, uint32_t sid)
+{
+ struct csession *ses_ptr;
+
+ down(&fcr->sem);
+ list_for_each_entry(ses_ptr, &fcr->list, entry) {
+ if(ses_ptr->sid == sid) {
+ down(&ses_ptr->sem);
+ break;
+ }
+ }
+ up(&fcr->sem);
+
+ return ses_ptr;
+}
+
+/* This is the main crypto function - feed it with plaintext
+ and get a ciphertext (or vice versa :-) */
+static int
+crypto_run(struct fcrypt *fcr, struct crypt_op *cop)
+{
+ char *data, *ivp;
+ char __user *src, __user *dst;
+ struct scatterlist sg;
+ struct csession *ses_ptr;
+ unsigned int ivsize;
+ size_t nbytes, bufsize;
+ int ret = 0;
+ struct blkcipher_desc desc;
+
+ nbytes = cop->len;
+
+ if (cop->op != COP_ENCRYPT && cop->op != COP_DECRYPT) {
+ dprintk(1, KERN_DEBUG, "invalid operation op=%u\n", cop->op);
+ return -EINVAL;
+ }
+
+ ses_ptr = crypto_get_session_by_sid(fcr, cop->ses);
+ if (!ses_ptr) {
+ dprintk(1, KERN_ERR, "invalid session ID=0x%08X\n", cop->ses);
+ return -EINVAL;
+ }
+
+ if (nbytes % crypto_blkcipher_blocksize(ses_ptr->tfm)) {
+ dprintk(1, KERN_ERR,
+ "data size (%zu) isn't a multiple of block size (%u)\n",
+ nbytes, crypto_blkcipher_blocksize(ses_ptr->tfm));
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+
+ bufsize = PAGE_SIZE < nbytes ? PAGE_SIZE : nbytes;
+ data = (char*)__get_free_page(GFP_KERNEL);
+
+ if (unlikely(!data)) {
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+
+ ivsize = crypto_blkcipher_ivsize(ses_ptr->tfm);
+
+ ivp = kmalloc(ivsize, GFP_KERNEL);
+ if (unlikely(!ivp)) {
+ free_page((unsigned long)data);
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+
+ if (cop->iv) {
+ copy_from_user(ivp, cop->iv, ivsize);
+ crypto_blkcipher_set_iv(ses_ptr->tfm, ivp, ivsize);
+ }
+
+ src = cop->src;
+ dst = cop->dst;
+
+ desc.tfm = ses_ptr->tfm;
+ desc.info = NULL;
+ desc.flags = 0;
+
+ while (nbytes > 0) {
+ size_t current_len = nbytes > bufsize ? bufsize : nbytes;
+
+ copy_from_user(data, src, current_len);
+
+ sg_set_buf(&sg, data, current_len);
+
+ if (cop->op == COP_DECRYPT)
+ ret = crypto_blkcipher_decrypt(&desc, &sg, &sg, current_len);
+ else
+ ret = crypto_blkcipher_encrypt(&desc, &sg, &sg, current_len);
+
+ if (unlikely(ret)) {
+ dprintk(0, KERN_ERR, "CryptoAPI failure: flags=0x%x\n",
+ crypto_blkcipher_tfm(ses_ptr->tfm)->crt_flags);
+ goto out;
+ }
+
+ copy_to_user(dst, data, current_len);
+
+ nbytes -= current_len;
+ src += current_len;
+ dst += current_len;
+ }
+
+#if defined(CRYPTODEV_STATS)
+ if (enable_stats) {
+ /* this is safe - we check cop->op at the function entry */
+ ses_ptr->stat[cop->op] += cop->len;
+ if (ses_ptr->stat_max_size < cop->len)
+ ses_ptr->stat_max_size = cop->len;
+ ses_ptr->stat_count++;
+ }
+#endif
+
+out:
+ free_page((unsigned long)data);
+
+ kfree(ivp);
+
+out_unlock:
+ up(&ses_ptr->sem);
+
+ return ret;
+}
+
+/* ====== /dev/crypto ====== */
+
+static int
+cryptodev_open(struct inode *inode, struct file *filp)
+{
+ struct fcrypt *fcr;
+
+ fcr = kmalloc(sizeof(*fcr), GFP_KERNEL);
+ if(!fcr)
+ return -ENOMEM;
+
+ memset(fcr, 0, sizeof(*fcr));
+ sema_init(&fcr->sem, 1);
+ INIT_LIST_HEAD(&fcr->list);
+ filp->private_data = fcr;
+
+ return 0;
+}
+
+static int
+cryptodev_release(struct inode *inode, struct file *filp)
+{
+ struct fcrypt *fcr = filp->private_data;
+
+ if(fcr) {
+ crypto_finish_all_sessions(fcr);
+ kfree(fcr);
+ filp->private_data = NULL;
+ }
+ return 0;
+}
+
+static int
+clonefd(struct file *filp)
+{
+ int fd;
+
+ fd = get_unused_fd();
+ if (fd >= 0) {
+ get_file(filp);
+ fd_install(fd, filp);
+ }
+
+ return fd;
+}
+
+static int
+cryptodev_ioctl(struct file *filp,
+ unsigned int cmd, unsigned long arg)
+{
+ struct session_op sop;
+ struct crypt_op cop;
+ struct fcrypt *fcr = filp->private_data;
+ uint32_t ses;
+ int ret, fd;
+
+ if (!fcr)
+ BUG();
+
+ switch (cmd) {
+ case CRIOGET:
+ fd = clonefd(filp);
+ put_user(fd, (int*)arg);
+ return 0;
+
+ case CIOCGSESSION:
+ copy_from_user(&sop, (void*)arg, sizeof(sop));
+ ret = crypto_create_session(fcr, &sop);
+ if (ret)
+ return ret;
+ copy_to_user((void*)arg, &sop, sizeof(sop));
+ return 0;
+
+ case CIOCFSESSION:
+ get_user(ses, (uint32_t*)arg);
+ ret = crypto_finish_session(fcr, ses);
+ return ret;
+
+ case CIOCCRYPT:
+ copy_from_user(&cop, (void*)arg, sizeof(cop));
+ ret = crypto_run(fcr, &cop);
+ copy_to_user((void*)arg, &cop, sizeof(cop));
+ return ret;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+struct file_operations cryptodev_fops = {
+ .owner = THIS_MODULE,
+ .open = cryptodev_open,
+ .release = cryptodev_release,
+ .unlocked_ioctl = cryptodev_ioctl,
+};
+
+struct miscdevice cryptodev = {
+ .minor = CRYPTODEV_MINOR,
+ .name = "crypto",
+ .fops = &cryptodev_fops,
+};
+
+static int
+cryptodev_register(void)
+{
+ int rc;
+
+ rc = misc_register (&cryptodev);
+ if (rc) {
+ printk(KERN_ERR PFX "registeration of /dev/crypto failed\n");
+ return rc;
+ }
+
+ return 0;
+}
+
+static void
+cryptodev_deregister(void)
+{
+ misc_deregister(&cryptodev);
+}
+
+/* ====== Module init/exit ====== */
+
+int __init
+init_cryptodev(void)
+{
+ int rc;
+
+ rc = cryptodev_register();
+ if (rc)
+ return rc;
+
+ printk(KERN_INFO PFX "driver loaded.\n");
+
+ return 0;
+}
+
+void __exit
+exit_cryptodev(void)
+{
+ cryptodev_deregister();
+ printk(KERN_INFO PFX "driver unloaded.\n");
+}
+
+module_init(init_cryptodev);
+module_exit(exit_cryptodev);
projects / karo-tx-linux.git / commitdiff