BUG/MINOR: http-htx: Don't by-pass HTX API when merging cookie values

http_cookie_merge() function is responsible to add a cookie header and merge
all values from a list. However, it was performed by appending values by
hand, using the pointer to the header value and changing the block
length. This was totally by-passing the HTX API.

For now, there is now bug because the function is called by h2 and quic
muxes when a HTTP message is parsed. And the cookie header is the last one
inserted. The HTX message is never fragmented and data from other blocs
cannot be overwritten. But, it could be an issue if it is called in another
context, from the HTTP analysis for instance.

To fix the issue, the function now relies on htx_replace_blk_value()
function to add the value separator first and then a cookie value.

This patch must be backported as far as 2.6.

diff --git a/src/http_htx.c b/src/http_htx.c
index 5db9fe17c0c2923beea862359fdc0fad64ac7298..3d77e3aa817df73901b11c97a97a102054890ba6 100644 (file)
--- a/src/http_htx.c
+++ b/src/http_htx.c
@@ -1956,11 +1956,8 @@ void http_cookie_register(struct http_hdr *list, int idx, int *first, int *last)
  */
 int http_cookie_merge(struct htx *htx, struct http_hdr *list, int first)
 {
-       uint32_t fs; /* free space */
-       uint32_t bs; /* block size */
-       uint32_t vl; /* value len */
-       uint32_t tl; /* total length */
        struct htx_blk *blk;
+       struct ist v;
 
        if (first < 0)
                return 0;
@@ -1969,28 +1966,16 @@ int http_cookie_merge(struct htx *htx, struct http_hdr *list, int first)
        if (!blk)
                return 1;
 
-       tl = list[first].v.len;
-       fs = htx_free_data_space(htx);
-       bs = htx_get_blksz(blk);
-
-       /* for each extra cookie, we'll extend the cookie's value and insert
-        * ";" before the new value.
-        */
-       fs += tl; /* first one is already counted */
-
-       /* Loop over cookies linked list built from http_cookie_register. */
        while ((first = list[first].n.len) >= 0) {
-               vl = list[first].v.len;
-               tl += vl + 2;
-               if (tl > fs)
+               v = htx_get_blk_value(htx, blk);
+               blk = htx_replace_blk_value(htx, blk, ist2(istend(v), 0), ist("; "));
+               if (!blk)
                        return 1;
 
-               htx_change_blk_value_len(htx, blk, tl);
-               *(char *)(htx_get_blk_ptr(htx, blk) + bs + 0) = ';';
-               *(char *)(htx_get_blk_ptr(htx, blk) + bs + 1) = ' ';
-               memcpy(htx_get_blk_ptr(htx, blk) + bs + 2,
-                      list[first].v.ptr, vl);
-               bs += vl + 2;
+               v = htx_get_blk_value(htx, blk);
+               blk = htx_replace_blk_value(htx, blk, ist2(istend(v), 0), list[first].v);
+               if (!blk)
+                       return 1;
        }
 
        return 0;