Re: Possibly solved invalid free() in git-remote-http from Git 1.7.2.1

On Mon, Aug 1, 2011 at 17:22, Ævar Arnfjörð Bjarmason <avarab@gmail.com> wrote:

Actually this is still an issue in master, CC-ing Tay who introduced this error.

This evil hack would get around it most of the time, but would introduce another race condition:

    diff --git a/http.c b/http.c
    index a1ea3db..ba81158 100644
    --- a/http.c
    +++ b/http.c
    @@ -1212,6 +1212,7 @@ struct http_object_request
*new_http_object_request(const char *base_url,
            ssize_t prev_read = 0;
            long prev_posn = 0;
            char range[RANGE_HEADER_SIZE];
    +       int allocated_url = 0;
            struct curl_slist *range_header = NULL;
            struct http_object_request *freq;

    @@ -1260,6 +1261,7 @@ struct http_object_request
*new_http_object_request(const char *base_url,
            git_SHA1_Init(&freq->c);

            freq->url = get_remote_object_url(base_url, hex, 0);
    +       allocated_url = 1;

            /*
             * If a previous temp file is present, process what was already
    @@ -1330,7 +1332,8 @@ struct http_object_request
*new_http_object_request(const char *base_url,

     abort:
            free(filename);
    -       free(freq->url);
    +       if (allocated_url)
    +               free(freq->url);
            free(freq);
            return NULL;
     }

One option would be to memzero freq, but that'll trip up xmalloc which tries to set things to 0xA5 under XMALLOC_POISON. I don't know what the proper way to solve this would be.