1 files changed, 150 insertions, 22 deletions

diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index cbc18b4a9cb2..357bd27a7fd1 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -24,12 +24,156 @@
 #include "../smbfs_common/arc4.h"
 #include <crypto/aead.h>
 
+/*
+ * Hash data from a BVEC-type iterator.
+ */
+static int cifs_shash_bvec(const struct iov_iter *iter, ssize_t maxsize,
+			   struct shash_desc *shash)
+{
+	const struct bio_vec *bv = iter->bvec;
+	unsigned long start = iter->iov_offset;
+	unsigned int i;
+	void *p;
+	int ret;
+
+	for (i = 0; i < iter->nr_segs; i++) {
+		size_t off, len;
+
+		len = bv[i].bv_len;
+		if (start >= len) {
+			start -= len;
+			continue;
+		}
+
+		len = min_t(size_t, maxsize, len - start);
+		off = bv[i].bv_offset + start;
+
+		p = kmap_local_page(bv[i].bv_page);
+		ret = crypto_shash_update(shash, p + off, len);
+		kunmap_local(p);
+		if (ret < 0)
+			return ret;
+
+		maxsize -= len;
+		if (maxsize <= 0)
+			break;
+		start = 0;
+	}
+
+	return 0;
+}
+
+/*
+ * Hash data from a KVEC-type iterator.
+ */
+static int cifs_shash_kvec(const struct iov_iter *iter, ssize_t maxsize,
+			   struct shash_desc *shash)
+{
+	const struct kvec *kv = iter->kvec;
+	unsigned long start = iter->iov_offset;
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < iter->nr_segs; i++) {
+		size_t len;
+
+		len = kv[i].iov_len;
+		if (start >= len) {
+			start -= len;
+			continue;
+		}
+
+		len = min_t(size_t, maxsize, len - start);
+		ret = crypto_shash_update(shash, kv[i].iov_base + start, len);
+		if (ret < 0)
+			return ret;
+		maxsize -= len;
+
+		if (maxsize <= 0)
+			break;
+		start = 0;
+	}
+
+	return 0;
+}
+
+/*
+ * Hash data from an XARRAY-type iterator.
+ */
+static ssize_t cifs_shash_xarray(const struct iov_iter *iter, ssize_t maxsize,
+				 struct shash_desc *shash)
+{
+	struct folio *folios[16], *folio;
+	unsigned int nr, i, j, npages;
+	loff_t start = iter->xarray_start + iter->iov_offset;
+	pgoff_t last, index = start / PAGE_SIZE;
+	ssize_t ret = 0;
+	size_t len, offset, foffset;
+	void *p;
+
+	if (maxsize == 0)
+		return 0;
+
+	last = (start + maxsize - 1) / PAGE_SIZE;
+	do {
+		nr = xa_extract(iter->xarray, (void **)folios, index, last,
+				ARRAY_SIZE(folios), XA_PRESENT);
+		if (nr == 0)
+			return -EIO;
+
+		for (i = 0; i < nr; i++) {
+			folio = folios[i];
+			npages = folio_nr_pages(folio);
+			foffset = start - folio_pos(folio);
+			offset = foffset % PAGE_SIZE;
+			for (j = foffset / PAGE_SIZE; j < npages; j++) {
+				len = min_t(size_t, maxsize, PAGE_SIZE - offset);
+				p = kmap_local_page(folio_page(folio, j));
+				ret = crypto_shash_update(shash, p, len);
+				kunmap_local(p);
+				if (ret < 0)
+					return ret;
+				maxsize -= len;
+				if (maxsize <= 0)
+					return 0;
+				start += len;
+				offset = 0;
+				index++;
+			}
+		}
+	} while (nr == ARRAY_SIZE(folios));
+	return 0;
+}
+
+/*
+ * Pass the data from an iterator into a hash.
+ */
+static int cifs_shash_iter(const struct iov_iter *iter, size_t maxsize,
+			   struct shash_desc *shash)
+{
+	if (maxsize == 0)
+		return 0;
+
+	switch (iov_iter_type(iter)) {
+	case ITER_BVEC:
+		return cifs_shash_bvec(iter, maxsize, shash);
+	case ITER_KVEC:
+		return cifs_shash_kvec(iter, maxsize, shash);
+	case ITER_XARRAY:
+		return cifs_shash_xarray(iter, maxsize, shash);
+	default:
+		pr_err("cifs_shash_iter(%u) unsupported\n", iov_iter_type(iter));
+		WARN_ON_ONCE(1);
+		return -EIO;
+	}
+}
+
 int __cifs_calc_signature(struct smb_rqst *rqst,
-			struct TCP_Server_Info *server, char *signature,
-			struct shash_desc *shash)
+			  struct TCP_Server_Info *server, char *signature,
+			  struct shash_desc *shash)
 {
 	int i;
-	int rc;
+	ssize_t rc;
 	struct kvec *iov = rqst->rq_iov;
 	int n_vec = rqst->rq_nvec;
 
@@ -61,25 +205,9 @@ int __cifs_calc_signature(struct smb_rqst *rqst,
 		}
 	}
 
-	/* now hash over the rq_pages array */
-	for (i = 0; i < rqst->rq_npages; i++) {
-		void *kaddr;
-		unsigned int len, offset;
-
-		rqst_page_get_length(rqst, i, &len, &offset);
-
-		kaddr = (char *) kmap(rqst->rq_pages[i]) + offset;
-
-		rc = crypto_shash_update(shash, kaddr, len);
-		if (rc) {
-			cifs_dbg(VFS, "%s: Could not update with payload\n",
-				 __func__);
-			kunmap(rqst->rq_pages[i]);
-			return rc;
-		}
-
-		kunmap(rqst->rq_pages[i]);
-	}
+	rc = cifs_shash_iter(&rqst->rq_iter, iov_iter_count(&rqst->rq_iter), shash);
+	if (rc < 0)
+		return rc;
 
 	rc = crypto_shash_final(shash, signature);
 	if (rc)