1 files changed, 309 insertions, 3 deletions

diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index ccd0ac8fa9a0..0bd732843fe7 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -16,6 +16,8 @@
 #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>
@@ -25,7 +27,45 @@
 #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
@@ -93,9 +133,246 @@ static void ima_free_tfm(struct crypto_shash *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 != ima_hash_algo && algo < HASH_ALGO__LAST) || !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)
@@ -156,7 +433,7 @@ out:
 	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;
@@ -173,6 +450,35 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
 }
 
 /*
+ * 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
  */
 static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,