#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
+#include <linux/moduleparam.h>
+#include <linux/ratelimit.h>
#include <linux/file.h>
#include <linux/crypto.h>
#include <linux/scatterlist.h>
#include <crypto/hash_info.h>
#include "ima.h"
+struct ahash_completion {
+ struct completion completion;
+ int err;
+};
+
+/* minimum file size for ahash use */
+static unsigned long ima_ahash_minsize;
+module_param_named(ahash_minsize, ima_ahash_minsize, ulong, 0644);
+MODULE_PARM_DESC(ahash_minsize, "Minimum file size for ahash use");
+
+/* default is 0 - 1 page. */
+static int ima_maxorder;
+static unsigned int ima_bufsize = PAGE_SIZE;
+
+static int param_set_bufsize(const char *val, const struct kernel_param *kp)
+{
+ unsigned long long size;
+ int order;
+
+ size = memparse(val, NULL);
+ order = get_order(size);
+ if (order >= MAX_ORDER)
+ return -EINVAL;
+ ima_maxorder = order;
+ ima_bufsize = PAGE_SIZE << order;
+ return 0;
+}
+
+static struct kernel_param_ops param_ops_bufsize = {
+ .set = param_set_bufsize,
+ .get = param_get_uint,
+};
+#define param_check_bufsize(name, p) __param_check(name, p, unsigned int)
+
+module_param_named(ahash_bufsize, ima_bufsize, bufsize, 0644);
+MODULE_PARM_DESC(ahash_bufsize, "Maximum ahash buffer size");
+
static struct crypto_shash *ima_shash_tfm;
+static struct crypto_ahash *ima_ahash_tfm;
/**
* ima_kernel_read - read file content
{
mm_segment_t old_fs;
char __user *buf = addr;
- ssize_t ret;
+ ssize_t ret = -EINVAL;
if (!(file->f_mode & FMODE_READ))
return -EBADF;
- if (!file->f_op->read && !file->f_op->aio_read)
- return -EINVAL;
old_fs = get_fs();
set_fs(get_ds());
if (file->f_op->read)
ret = file->f_op->read(file, buf, count, &offset);
- else
+ else if (file->f_op->aio_read)
ret = do_sync_read(file, buf, count, &offset);
+ else if (file->f_op->read_iter)
+ ret = new_sync_read(file, buf, count, &offset);
set_fs(old_fs);
return ret;
}
-int ima_init_crypto(void)
+int __init ima_init_crypto(void)
{
long rc;
struct crypto_shash *tfm = ima_shash_tfm;
int rc;
- if (algo != ima_hash_algo && algo < HASH_ALGO__LAST) {
+ if (algo < 0 || algo >= HASH_ALGO__LAST)
+ algo = ima_hash_algo;
+
+ if (algo != ima_hash_algo) {
tfm = crypto_alloc_shash(hash_algo_name[algo], 0, 0);
if (IS_ERR(tfm)) {
rc = PTR_ERR(tfm);
crypto_free_shash(tfm);
}
-/*
- * Calculate the MD5/SHA1 file digest
+/**
+ * ima_alloc_pages() - Allocate contiguous pages.
+ * @max_size: Maximum amount of memory to allocate.
+ * @allocated_size: Returned size of actual allocation.
+ * @last_warn: Should the min_size allocation warn or not.
+ *
+ * Tries to do opportunistic allocation for memory first trying to allocate
+ * max_size amount of memory and then splitting that until zero order is
+ * reached. Allocation is tried without generating allocation warnings unless
+ * last_warn is set. Last_warn set affects only last allocation of zero order.
+ *
+ * By default, ima_maxorder is 0 and it is equivalent to kmalloc(GFP_KERNEL)
+ *
+ * Return pointer to allocated memory, or NULL on failure.
*/
+static void *ima_alloc_pages(loff_t max_size, size_t *allocated_size,
+ int last_warn)
+{
+ void *ptr;
+ int order = ima_maxorder;
+ gfp_t gfp_mask = __GFP_WAIT | __GFP_NOWARN | __GFP_NORETRY;
+
+ if (order)
+ order = min(get_order(max_size), order);
+
+ for (; order; order--) {
+ ptr = (void *)__get_free_pages(gfp_mask, order);
+ if (ptr) {
+ *allocated_size = PAGE_SIZE << order;
+ return ptr;
+ }
+ }
+
+ /* order is zero - one page */
+
+ gfp_mask = GFP_KERNEL;
+
+ if (!last_warn)
+ gfp_mask |= __GFP_NOWARN;
+
+ ptr = (void *)__get_free_pages(gfp_mask, 0);
+ if (ptr) {
+ *allocated_size = PAGE_SIZE;
+ return ptr;
+ }
+
+ *allocated_size = 0;
+ return NULL;
+}
+
+/**
+ * ima_free_pages() - Free pages allocated by ima_alloc_pages().
+ * @ptr: Pointer to allocated pages.
+ * @size: Size of allocated buffer.
+ */
+static void ima_free_pages(void *ptr, size_t size)
+{
+ if (!ptr)
+ return;
+ free_pages((unsigned long)ptr, get_order(size));
+}
+
+static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo)
+{
+ struct crypto_ahash *tfm = ima_ahash_tfm;
+ int rc;
+
+ if (algo < 0 || algo >= HASH_ALGO__LAST)
+ algo = ima_hash_algo;
+
+ if (algo != ima_hash_algo || !tfm) {
+ tfm = crypto_alloc_ahash(hash_algo_name[algo], 0, 0);
+ if (!IS_ERR(tfm)) {
+ if (algo == ima_hash_algo)
+ ima_ahash_tfm = tfm;
+ } else {
+ rc = PTR_ERR(tfm);
+ pr_err("Can not allocate %s (reason: %d)\n",
+ hash_algo_name[algo], rc);
+ }
+ }
+ return tfm;
+}
+
+static void ima_free_atfm(struct crypto_ahash *tfm)
+{
+ if (tfm != ima_ahash_tfm)
+ crypto_free_ahash(tfm);
+}
+
+static void ahash_complete(struct crypto_async_request *req, int err)
+{
+ struct ahash_completion *res = req->data;
+
+ if (err == -EINPROGRESS)
+ return;
+ res->err = err;
+ complete(&res->completion);
+}
+
+static int ahash_wait(int err, struct ahash_completion *res)
+{
+ switch (err) {
+ case 0:
+ break;
+ case -EINPROGRESS:
+ case -EBUSY:
+ wait_for_completion(&res->completion);
+ reinit_completion(&res->completion);
+ err = res->err;
+ /* fall through */
+ default:
+ pr_crit_ratelimited("ahash calculation failed: err: %d\n", err);
+ }
+
+ return err;
+}
+
+static int ima_calc_file_hash_atfm(struct file *file,
+ struct ima_digest_data *hash,
+ struct crypto_ahash *tfm)
+{
+ loff_t i_size, offset;
+ char *rbuf[2] = { NULL, };
+ int rc, read = 0, rbuf_len, active = 0, ahash_rc = 0;
+ struct ahash_request *req;
+ struct scatterlist sg[1];
+ struct ahash_completion res;
+ size_t rbuf_size[2];
+
+ hash->length = crypto_ahash_digestsize(tfm);
+
+ req = ahash_request_alloc(tfm, GFP_KERNEL);
+ if (!req)
+ return -ENOMEM;
+
+ init_completion(&res.completion);
+ ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
+ CRYPTO_TFM_REQ_MAY_SLEEP,
+ ahash_complete, &res);
+
+ rc = ahash_wait(crypto_ahash_init(req), &res);
+ if (rc)
+ goto out1;
+
+ i_size = i_size_read(file_inode(file));
+
+ if (i_size == 0)
+ goto out2;
+
+ /*
+ * Try to allocate maximum size of memory.
+ * Fail if even a single page cannot be allocated.
+ */
+ rbuf[0] = ima_alloc_pages(i_size, &rbuf_size[0], 1);
+ if (!rbuf[0]) {
+ rc = -ENOMEM;
+ goto out1;
+ }
+
+ /* Only allocate one buffer if that is enough. */
+ if (i_size > rbuf_size[0]) {
+ /*
+ * Try to allocate secondary buffer. If that fails fallback to
+ * using single buffering. Use previous memory allocation size
+ * as baseline for possible allocation size.
+ */
+ rbuf[1] = ima_alloc_pages(i_size - rbuf_size[0],
+ &rbuf_size[1], 0);
+ }
+
+ if (!(file->f_mode & FMODE_READ)) {
+ file->f_mode |= FMODE_READ;
+ read = 1;
+ }
+
+ for (offset = 0; offset < i_size; offset += rbuf_len) {
+ if (!rbuf[1] && offset) {
+ /* Not using two buffers, and it is not the first
+ * read/request, wait for the completion of the
+ * previous ahash_update() request.
+ */
+ rc = ahash_wait(ahash_rc, &res);
+ if (rc)
+ goto out3;
+ }
+ /* read buffer */
+ rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]);
+ rc = ima_kernel_read(file, offset, rbuf[active], rbuf_len);
+ if (rc != rbuf_len)
+ goto out3;
+
+ if (rbuf[1] && offset) {
+ /* Using two buffers, and it is not the first
+ * read/request, wait for the completion of the
+ * previous ahash_update() request.
+ */
+ rc = ahash_wait(ahash_rc, &res);
+ if (rc)
+ goto out3;
+ }
+
+ sg_init_one(&sg[0], rbuf[active], rbuf_len);
+ ahash_request_set_crypt(req, sg, NULL, rbuf_len);
+
+ ahash_rc = crypto_ahash_update(req);
+
+ if (rbuf[1])
+ active = !active; /* swap buffers, if we use two */
+ }
+ /* wait for the last update request to complete */
+ rc = ahash_wait(ahash_rc, &res);
+out3:
+ if (read)
+ file->f_mode &= ~FMODE_READ;
+ ima_free_pages(rbuf[0], rbuf_size[0]);
+ ima_free_pages(rbuf[1], rbuf_size[1]);
+out2:
+ if (!rc) {
+ ahash_request_set_crypt(req, NULL, hash->digest, 0);
+ rc = ahash_wait(crypto_ahash_final(req), &res);
+ }
+out1:
+ ahash_request_free(req);
+ return rc;
+}
+
+static int ima_calc_file_ahash(struct file *file, struct ima_digest_data *hash)
+{
+ struct crypto_ahash *tfm;
+ int rc;
+
+ tfm = ima_alloc_atfm(hash->algo);
+ if (IS_ERR(tfm))
+ return PTR_ERR(tfm);
+
+ rc = ima_calc_file_hash_atfm(file, hash, tfm);
+
+ ima_free_atfm(tfm);
+
+ return rc;
+}
+
static int ima_calc_file_hash_tfm(struct file *file,
struct ima_digest_data *hash,
struct crypto_shash *tfm)
return rc;
}
-int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
+static int ima_calc_file_shash(struct file *file, struct ima_digest_data *hash)
{
struct crypto_shash *tfm;
int rc;
return rc;
}
+/*
+ * ima_calc_file_hash - calculate file hash
+ *
+ * Asynchronous hash (ahash) allows using HW acceleration for calculating
+ * a hash. ahash performance varies for different data sizes on different
+ * crypto accelerators. shash performance might be better for smaller files.
+ * The 'ima.ahash_minsize' module parameter allows specifying the best
+ * minimum file size for using ahash on the system.
+ *
+ * If the ima.ahash_minsize parameter is not specified, this function uses
+ * shash for the hash calculation. If ahash fails, it falls back to using
+ * shash.
+ */
+int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
+{
+ loff_t i_size;
+ int rc;
+
+ i_size = i_size_read(file_inode(file));
+
+ if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
+ rc = ima_calc_file_ahash(file, hash);
+ if (!rc)
+ return 0;
+ }
+
+ return ima_calc_file_shash(file, hash);
+}
+
/*
* Calculate the hash of template data
*/
projects / mirror_ubuntu-bionic-kernel.git / blobdiff