wget: fix use-after-free of ->user. Closes 6836

function                                             old     new   delta
wget_main                                           2207    2223     +16
parse_url                                            339     353     +14

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 9 insertions, 7 deletions

diff --git a/networking/wget.c b/networking/wget.c
index d6c509edc..7ca947aec 100644
--- a/networking/wget.c
+++ b/networking/wget.c
@@ -46,7 +46,7 @@
 struct host_info {
         char *allocated;
         const char *path;
-        const char *user;
+        char       *user;
         char       *host;
         int         port;
         smallint    is_ftp;
@@ -322,9 +322,6 @@ static void parse_url(const char *src_url, struct host_info *h)
                 h->path = sp;
         }
 
-        // We used to set h->user to NULL here, but this interferes
-        // with handling of code 302 ("object was moved")
-
         sp = strrchr(h->host, '@');
         if (sp != NULL) {
                 // URL-decode "user:password" string before base64-encoding:
@@ -333,11 +330,13 @@ static void parse_url(const char *src_url, struct host_info *h)
                 // which decodes to "test:my pass".
                 // Standard wget and curl do this too.
                 *sp = '\0';
-                h->user = percent_decode_in_place(h->host, /*strict:*/ 0);
+                free(h->user);
+                h->user = xstrdup(percent_decode_in_place(h->host, /*strict:*/ 0));
                 h->host = sp + 1;
         }
-
-        sp = h->host;
+        /* else: h->user remains NULL, or as set by original request
+         * before redirect (if we are here after a redirect).
+         */
 }
 
 static char *gethdr(FILE *fp)
@@ -880,6 +879,7 @@ However, in real world it was observed that some web servers
                                 } else {
                                         parse_url(str, &target);
                                         if (!use_proxy) {
+                                                /* server.user remains untouched */
                                                 free(server.allocated);
                                                 server.allocated = NULL;
                                                 server.host = target.host;
@@ -929,6 +929,8 @@ However, in real world it was observed that some web servers
 
         free(server.allocated);
         free(target.allocated);
+        free(server.user);
+        free(target.user);
         free(fname_out_alloc);
         free(redirected_path);
 }