diff --git a/include/proto/buffers.h b/include/proto/buffers.h
index cec7b02..e061b2c 100644
--- a/include/proto/buffers.h
+++ b/include/proto/buffers.h
@@ -439,9 +439,9 @@
 }
 
 /* report 0 in case of error, 1 if OK. */
-static inline int chunk_initlen(struct chunk *chk, char *str, size_t size, size_t len) {
+static inline int chunk_initlen(struct chunk *chk, char *str, size_t size, int len) {
 
-	if (len > size)
+	if (size && len > size)
 		return 0;
 
 	chk->str  = str;
diff --git a/include/types/buffers.h b/include/types/buffers.h
index 133285f..fc070bd 100644
--- a/include/types/buffers.h
+++ b/include/types/buffers.h
@@ -149,7 +149,7 @@
 struct chunk {
 	char *str;	/* beginning of the string itself. Might not be 0-terminated */
 	size_t size;	/* total size of the buffer, 0 if the *str is read-only */
-	size_t len;	/* current size of the string from first to last char. <0 = uninit. */
+	int len;	/* current size of the string from first to last char. <0 = uninit. */
 };
 
 /* needed for a declaration below */
diff --git a/src/proto_http.c b/src/proto_http.c
index 4638d09..8698594 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -4596,8 +4596,7 @@
 			int len = txn->hdr_idx.v[cur_idx].len;
 			if (len > 14 &&
 			    !strncasecmp("Authorization:", h, 14)) {
-				txn->auth_hdr.str = h;
-				txn->auth_hdr.len = len;
+				chunk_initlen(&txn->auth_hdr, h, 0, len);
 				break;
 			}
 			h += len + txn->hdr_idx.v[cur_idx].cr + 1;