Hi Noah,
On Thu, Sep 09, 2021 at 01:28:21PM -0400, Noah Sanci via Elfutils-devel wrote:
> The attached patch %-escapes debuginfod url characters, then unescapes only
> '/' characters. Previously characters such as '+' were not escaped and caused
> improper escaping further on in handler_cb.
> https://sourceware.org/bugzilla/show_bug.cgi?id=28034.
>
> On Wed, Sep 8, 2021 at 9:38 AM Mark Wielaard <m...@klomp.org> wrote:
> > /* Initialize each handle. */
> > for (int i = 0; i < num_urls; i++)
> >
> > So you only need to escape once. You of course then need to make sure
> > the escaped_string is freed after the loop.
> Added
>
> > We already check that the first char is a '/'. It seems silly to curl
> > escape that one and then unescape it again. So maybe curl_easy_escape
> > (data[i].handle, filename + 1, 0) and then change the snprintf pattern
> > to "%s/%s/%s/%s"?
> > ^ the slash got readded here.
> Added
>
> > The strlen inside the while loop can also be done outside and then
> > calculated instead of running strlen on the tail every time.
> Added
Thanks. I do have one more performance nitpick (sorry).
> + char *escaped_string;
> + if (filename)
> + escaped_string = curl_easy_escape(&target_handle, filename+1, 0);
The escaped_string is created outside the loop and reused each time
(good). But...
> +
> /* Initialize each handle. */
> for (int i = 0; i < num_urls; i++)
> {
> @@ -904,16 +908,23 @@ debuginfod_query_server (debuginfod_client *c,
> if (filename) /* must start with / */
> {
> /* PR28034 escape characters in completed url to %hh format. */
> - char *escaped_string;
> - escaped_string = curl_easy_escape(data[i].handle, filename, 0);
> + char *loc = escaped_string;
> if (!escaped_string)
> {
> rc = -ENOMEM;
> goto out2;
> }
This check, and...
> +
> + size_t escaped_strlen = strlen(escaped_string);
> + while ((loc = strstr(loc, "%2F")))
> + {
> + loc[0] = '/';
> + // pull the string back after replacement
> + memmove(loc+1, loc+3,escaped_strlen - (loc - escaped_string
> + 2) );
> + escaped_strlen -=2;
> + }
the manipulation of the escaped_string, could both also be done
outside the loop, since they always do the same thing.
> snprintf(data[i].url, PATH_MAX, "%s/%s/%s/%s", server_url,
> build_id_bytes, type, escaped_string);
> - curl_free(escaped_string);
> }
> else
> snprintf(data[i].url, PATH_MAX, "%s/%s/%s", server_url,
> build_id_bytes, type);
> @@ -953,6 +964,7 @@ debuginfod_query_server (debuginfod_client *c,
> curl_multi_add_handle(curlm, data[i].handle);
> }
>
> + if (filename) curl_free(escaped_string);
And released after the loop. Good.
> /* Query servers in parallel. */
> if (vfd >= 0)
> dprintf (vfd, "query %d urls in parallel\n", num_urls);
> diff --git a/tests/ChangeLog b/tests/ChangeLog
> index 85dca442..b84f420c 100644
> --- a/tests/ChangeLog
> +++ b/tests/ChangeLog
> @@ -132,11 +132,8 @@
> 2021-07-16 Noah Sanci <nsa...@redhat.com>
>
> PR28034
> - * run-debuginfod-find.sh: Added a test ensuring files with %
> - escapable characters in their paths are accessible. The test
> - itself is changing the name of a binary known previously as prog to
> - p+r%o$g. General operations such as accessing p+r%o$g acts as the
> - test for %-escape checking.
> + * run-debuginfod-percent-escape.sh: Added a test ensuring files with %
> + escapable characters in their paths are accessible.
I think you should simply add a new ChangeLog entry at the top instead
of changing an old existing one. And please do mention the Makefile.am
(TESTS) and (EXTRA_DIST) addition.
> 2021-07-21 Noah Sanci <nsa...@redhat.com>
>
> diff --git a/tests/Makefile.am b/tests/Makefile.am
> index c586422e..ee17d3b1 100644
> --- a/tests/Makefile.am
> +++ b/tests/Makefile.am
> @@ -231,6 +231,7 @@ TESTS += run-debuginfod-dlopen.sh \
> run-debuginfod-federation-sqlite.sh \
> run-debuginfod-federation-link.sh \
> run-debuginfod-federation-metrics.sh \
> + run-debuginfod-percent-escape.sh \
> run-debuginfod-x-forwarded-for.sh
> endif
> endif
> @@ -515,6 +516,7 @@ EXTRA_DIST = run-arextract.sh run-arsymtest.sh run-ar.sh \
> run-debuginfod-archive-groom.sh \
> run-debuginfod-archive-rename.sh \
> run-debuginfod-archive-test.sh \
> + run-debuginfod-percent-escape.sh \
> debuginfod-rpms/fedora30/hello2-1.0-2.src.rpm \
> debuginfod-rpms/fedora30/hello2-1.0-2.x86_64.rpm \
> debuginfod-rpms/fedora30/hello2-debuginfo-1.0-2.x86_64.rpm \
> +env DEBUGINFOD_CACHE_PATH=${PWD}/.client_cache
> DEBUGINFOD_URLS="http://127.0.0.1:$PORT1"; \
> + LD_LIBRARY_PATH=$ldpath ${abs_top_builddir}/debuginfod/debuginfod-find
> -vvv source F/p++r\$\#o^^g ${abs_builddir}/F/p++r\$\#o^^g.c > vlog1 2>&1 ||
> true
> +tempfiles vlog1
> +grep 'F/p%2B%2Br%24%23o%5E%5Eg.Ac' vlog1
OK, that is certainly a file name with lots of unexpected characters :)
Thanks,
Mark
