[Fix] Normalize URLs with multiple slashes between host and path

Fixes #5773: URLs like https://example.com//path were not being
normalized. The extra slashes between host and path are now collapsed
to a single slash during URL parsing.

diff --git a/src/libserver/url.c b/src/libserver/url.c
index d93a5c03af53ec78d9105ef44894400209e6e875..26d3b310a7aff4f78bf7cea9b0058e7166b6ea90 100644 (file)
--- a/src/libserver/url.c
+++ b/src/libserver/url.c
@@ -2251,7 +2251,7 @@ rspamd_url_lua_consult(const char *url_str,
 
        /* Try to load lua_url_filter.filter_url_string function */
        if (!rspamd_lua_require_function(L, "lua_url_filter", "filter_url_string")) {
-               lua_pop(L, 1); /* Remove error handler */
+               lua_pop(L, 1);                       /* Remove error handler */
                return RSPAMD_URL_LUA_FILTER_ACCEPT; /* Filter not available, accept */
        }
 
@@ -2269,7 +2269,7 @@ rspamd_url_lua_consult(const char *url_str,
        if ((ret = lua_pcall(L, 2, 1, err_idx)) != 0) {
                msg_err("cannot call lua_url_filter.filter_url_string: %s",
                                lua_isstring(L, -1) ? lua_tostring(L, -1) : "unknown error");
-               lua_pop(L, 2); /* Error + error handler */
+               lua_pop(L, 2);                       /* Error + error handler */
                return RSPAMD_URL_LUA_FILTER_ACCEPT; /* On error, accept */
        }
 
@@ -2442,6 +2442,64 @@ rspamd_url_parse(struct rspamd_url *uri,
 
        rspamd_url_shift(uri, unquoted_len, UF_HOST);
 
+       /*
+        * Remove extra slashes between host and path.
+        * URLs like https://example.com//path should be normalized to https://example.com/path
+        * The slashes between host end and path start are not part of either component,
+        * so we need to handle them explicitly here.
+        */
+       if (uri->datalen > 0) {
+               /* Calculate where host ends: hostshift + hostlen */
+               unsigned int host_end = uri->hostshift + uri->hostlen;
+               /* Path starts at datashift */
+               unsigned int path_start = uri->datashift;
+
+               /*
+                * Between host_end and path_start we should have exactly one slash.
+                * Any additional slashes (or backslashes) need to be removed.
+                * Expected structure: "...host/" + "path..." where datashift points to 'p'
+                * If we have "...host//" + "path...", the extra '/' needs removal.
+                */
+               if (path_start > host_end + 1) {
+                       /* Check if the gap contains only slashes */
+                       unsigned int gap_start = host_end;
+                       unsigned int gap_len = path_start - host_end;
+                       gboolean all_slashes = TRUE;
+
+                       for (unsigned int i = 0; i < gap_len; i++) {
+                               char c = uri->string[gap_start + i];
+                               if (c != '/' && c != '\\') {
+                                       all_slashes = FALSE;
+                                       break;
+                               }
+                       }
+
+                       if (all_slashes && gap_len > 1) {
+                               /* Remove extra slashes, keep only one */
+                               unsigned int extra_slashes = gap_len - 1;
+                               unsigned int remain = uri->urllen - path_start;
+
+                               /* Shift path and everything after it backward */
+                               memmove(uri->string + host_end + 1,
+                                               uri->string + path_start,
+                                               remain);
+
+                               /* Null terminate */
+                               uri->urllen -= extra_slashes;
+                               uri->string[uri->urllen] = '\0';
+
+                               /* Adjust all offsets that come after host */
+                               uri->datashift -= extra_slashes;
+                               if (uri->querylen > 0) {
+                                       uri->queryshift -= extra_slashes;
+                               }
+                               if (uri->fragmentlen > 0) {
+                                       uri->fragmentshift -= extra_slashes;
+                               }
+                       }
+               }
+       }
+
        if (rspamd_url_remove_dots(uri)) {
                uri->flags |= RSPAMD_URL_FLAG_OBSCURED;
        }