diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index a6ef088e057b..d3e14d1fc0b5 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -37,6 +37,7 @@
 #include <crypto/aead.h>
 
 int __cifs_calc_signature(struct smb_rqst *rqst,
+			int start,
 			struct TCP_Server_Info *server, char *signature,
 			struct shash_desc *shash)
 {
@@ -45,10 +46,7 @@ int __cifs_calc_signature(struct smb_rqst *rqst,
 	struct kvec *iov = rqst->rq_iov;
 	int n_vec = rqst->rq_nvec;
 
-	if (n_vec < 2 || iov[0].iov_len != 4)
-		return -EIO;
-
-	for (i = 1; i < n_vec; i++) {
+	for (i = start; i < n_vec; i++) {
 		if (iov[i].iov_len == 0)
 			continue;
 		if (iov[i].iov_base == NULL) {
@@ -119,7 +117,7 @@ static int cifs_calc_signature(struct smb_rqst *rqst,
 		return rc;
 	}
 
-	return __cifs_calc_signature(rqst, server, signature,
+	return __cifs_calc_signature(rqst, 1, server, signature,
 				     &server->secmech.sdescmd5->shash);
 }
 
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 7933c5f9c076..7f0c773d5f6b 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -544,7 +544,7 @@ int cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 			   struct cifs_sb_info *cifs_sb,
 			   const unsigned char *path, char *pbuf,
 			   unsigned int *pbytes_written);
-int __cifs_calc_signature(struct smb_rqst *rqst,
+int __cifs_calc_signature(struct smb_rqst *rqst, int start,
 			struct TCP_Server_Info *server, char *signature,
 			struct shash_desc *shash);
 enum securityEnum cifs_select_sectype(struct TCP_Server_Info *,
diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
index 2c671123a6bf..349d5ccf854c 100644
--- a/fs/cifs/smb2transport.c
+++ b/fs/cifs/smb2transport.c
@@ -171,7 +171,9 @@ smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 	unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
 	unsigned char *sigptr = smb2_signature;
 	struct kvec *iov = rqst->rq_iov;
-	struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)iov[1].iov_base;
+	int iov_hdr_index = rqst->rq_nvec > 1 ? 1 : 0;
+	struct smb2_sync_hdr *shdr =
+		(struct smb2_sync_hdr *)iov[iov_hdr_index].iov_base;
 	struct cifs_ses *ses;
 
 	ses = smb2_find_smb_ses(server, shdr->SessionId);
@@ -202,7 +204,7 @@ smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 		return rc;
 	}
 
-	rc = __cifs_calc_signature(rqst, server, sigptr,
+	rc = __cifs_calc_signature(rqst, iov_hdr_index,  server, sigptr,
 		&server->secmech.sdeschmacsha256->shash);
 
 	if (!rc)
@@ -412,7 +414,9 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 	unsigned char smb3_signature[SMB2_CMACAES_SIZE];
 	unsigned char *sigptr = smb3_signature;
 	struct kvec *iov = rqst->rq_iov;
-	struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)iov[1].iov_base;
+	int iov_hdr_index = rqst->rq_nvec > 1 ? 1 : 0;
+	struct smb2_sync_hdr *shdr =
+		(struct smb2_sync_hdr *)iov[iov_hdr_index].iov_base;
 	struct cifs_ses *ses;
 
 	ses = smb2_find_smb_ses(server, shdr->SessionId);
@@ -443,7 +447,7 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 		return rc;
 	}
 
-	rc = __cifs_calc_signature(rqst, server, sigptr,
+	rc = __cifs_calc_signature(rqst, iov_hdr_index, server, sigptr,
 				   &server->secmech.sdesccmacaes->shash);
 
 	if (!rc)