Re: [PATCH v3 3/4] enter_repo: do not modify input

From: Phil Hord <phil.hord@gmail.com>
Date: Oct 4, 2011, 17:55 UTC
Message-ID: <CABURp0qDsxHwsuyvB6-KvKPrKuUT0-Fpr730TD_TxxFY7fotpA@mail.gmail.com>
In-Reply-To: <1317329963-6656-4-git-send-email-kusmabite@gmail.com>

On Thu, Sep 29, 2011 at 4:59 PM, Erik Faye-Lund <kusmabite@gmail.com> wrote:

> entr_repo(..., 0) currently modifies the input to strip away
> trailing slashes. This means that we some times need to copy the
> input to keep the original.

I'm also modifying enter_repo() so I'm looking a bit closer at this patch now.

Show 5 quoted lines

> Change it to unconditionally copy it into the used_path buffer so
> we can safely use the input without having to copy it.
>
> Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
> ---

[...]

Show 21 quoted lines

>  */
> -char *enter_repo(char *path, int strict)
> +const char *enter_repo(const char *path, int strict)
>  {
>        static char used_path[PATH_MAX];
>        static char validated_path[PATH_MAX];
> @@ -297,14 +297,15 @@ char *enter_repo(char *path, int strict)
>                };
>                int len = strlen(path);
>                int i;
> -               while ((1 < len) && (path[len-1] == '/')) {
> -                       path[len-1] = 0;
> +               while ((1 < len) && (path[len-1] == '/'))
>                        len--;
> -               }
> +
>                if (PATH_MAX <= len)
>                        return NULL;
> -               if (path[0] == '~') {
> -                       char *newpath = expand_user_path(path);
> +               strncpy(used_path, path, len);

When len < strlen(path), this will will leave used_path unterminated.

Show 13 quoted lines

> +
> +               if (used_path[0] == '~') {
> +                       char *newpath = expand_user_path(used_path);
>                        if (!newpath || (PATH_MAX - 10 < strlen(newpath))) {
>                                free(newpath);
>                                return NULL;
> @@ -316,24 +317,21 @@ char *enter_repo(char *path, int strict)
>                         * anyway.
>                         */
>                        strcpy(used_path, newpath); free(newpath);
> -                       strcpy(validated_path, path);
> -                       path = used_path;
> +                       strcpy(validated_path, used_path);

The point of 'validated_path' is to keep the original unmolested, unexpanded path string (plus DWIM suffix), but here you've just replaced validated_path with a copy of the expanded_user_path. On the other hand, we seem always to strcpy(validated_path , path), so we might as well get that done up-front.

I'll re-roll these changes in in a minute.  Stand by.

Phil