[FFmpeg-devel] [PATCH v3] avformat/url: check url root node when rel include double dot

[Nicolas George]

Steven Liu (12020-04-27):
> fix ticket: 8625
> and add testcase into url for double dot corner case
> 
> Signed-off-by: Steven Liu <liuqi05 at kuaishou.com>
> ---
>  libavformat/tests/url.c |  3 +++
>  libavformat/url.c       | 21 +++++++++++++++++++--
>  tests/ref/fate/url      |  3 +++
>  3 files changed, 25 insertions(+), 2 deletions(-)
> 
> diff --git a/libavformat/tests/url.c b/libavformat/tests/url.c
> index 5e484fd428..02d0d59aa8 100644
> --- a/libavformat/tests/url.c
> +++ b/libavformat/tests/url.c
> @@ -56,6 +56,7 @@ int main(void)
>      test("/foo/bar", "baz");
>      test("/foo/bar", "../baz");
>      test("/foo/bar", "/baz");
> +    test("/foo/bar", "../../../baz");
>      test("http://server/foo/", "baz");
>      test("http://server/foo/bar", "baz");
>      test("http://server/foo/", "../baz");
> @@ -65,6 +66,8 @@ int main(void)
>      test("http://server/foo/bar?param=value/with/slashes", "/baz");
>      test("http://server/foo/bar?param&otherparam", "?someparam");
>      test("http://server/foo/bar", "//other/url");
> +    test("http://server/foo/bar", "../../../../../other/url");
> +    test("http://server/foo/bar", "/../../../../../other/url");
>  
>      printf("\nTesting av_url_split:\n");
>      test2("/foo/bar");
> diff --git a/libavformat/url.c b/libavformat/url.c
> index 596fb49cfc..0aa50ab9a7 100644
> --- a/libavformat/url.c
> +++ b/libavformat/url.c
> @@ -81,6 +81,7 @@ void ff_make_absolute_url(char *buf, int size, const char *base,
>                            const char *rel)
>  {
>      char *sep, *path_query;
> +    char *root, *p;
>      /* Absolute path, relative to the current server */
>      if (base && strstr(base, "://") && rel[0] == '/') {
>          if (base != buf)
> @@ -120,16 +121,32 @@ void ff_make_absolute_url(char *buf, int size, const char *base,
>          return;
>      }
>  
> +    root = p = buf;
> +    /* Get the path root of the url which start by "://" */
> +    if (p && strstr(p, "://")) {
> +        sep = strstr(p, "://");
> +        if (sep) {
> +            sep += 3;
> +            root = strchr(sep, '/');
> +        }
> +    }
> +
>      /* Remove the file name from the base url */
>      sep = strrchr(buf, '/');
> +    if (sep <= root)
> +        sep = root;
> +
>      if (sep)
>          sep[1] = '\0';
>      else
>          buf[0] = '\0';
>      while (av_strstart(rel, "../", NULL) && sep) {
>          /* Remove the path delimiter at the end */
> -        sep[0] = '\0';
> -        sep = strrchr(buf, '/');
> +        if (sep > root) {
> +            sep[0] = '\0';
> +            sep = strrchr(buf, '/');
> +        }
> +
>          /* If the next directory name to pop off is "..", break here */
>          if (!strcmp(sep ? &sep[1] : buf, "..")) {
>              /* Readd the slash we just removed */
> diff --git a/tests/ref/fate/url b/tests/ref/fate/url
> index 980b2ce1f9..c8260a97be 100644
> --- a/tests/ref/fate/url
> +++ b/tests/ref/fate/url
> @@ -3,6 +3,7 @@ Testing ff_make_absolute_url:
>                                            /foo/bar baz                  => /foo/baz
>                                            /foo/bar ../baz               => /baz
>                                            /foo/bar /baz                 => /baz
> +                                          /foo/bar ../../../baz         => /baz
>                                  http://server/foo/ baz                  => http://server/foo/baz
>                               http://server/foo/bar baz                  => http://server/foo/baz
>                                  http://server/foo/ ../baz               => http://server/baz
> @@ -12,6 +13,8 @@ Testing ff_make_absolute_url:
>      http://server/foo/bar?param=value/with/slashes /baz                 => http://server/baz
>              http://server/foo/bar?param&otherparam ?someparam           => http://server/foo/bar?someparam
>                               http://server/foo/bar //other/url          => http://other/url
> +                             http://server/foo/bar ../../../../../other/url => http://server/other/url

> +                             http://server/foo/bar /../../../../../other/url => http://server/../../../../../other/url

Is this supposed to be the proper result?

>  
>  Testing av_url_split:
>  /foo/bar                                                     =>                                                    -1 /foo/bar

Regards,

-- 
  Nicolas George
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