On Mon, 2016-04-11 at 00:03 +0100, Ramsay Jones wrote:
> It took me a few minutes to convince myself that, if index-helper is
> the only writer for the symlink, that the call to readlink would
> result in a properly NULL terminated string. This relies on the
> initialization of the address variable setting each byte of the
> 'struct sockaddr_un' to zero and the contents of the symlink being
> no more than 'sizeof(address.sun_path) - 1' bytes long.
>
> In order to make the call easier to reason about, introduce a wrapper
> function, read_link(), which copes with overlong symlinks and ensures
> correct NULL termination.
>
> Signed-off-by: Ramsay Jones <ramsay@xxxxxxxxxxxxxxxxxxxx>
> ---
> read-cache.c | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/read-cache.c b/read-cache.c
> index c7053d8..39330a1 100644
> --- a/read-cache.c
> +++ b/read-cache.c
> @@ -1722,12 +1722,23 @@ static void post_read_index_from(struct
> index_state *istate)
> tweak_untracked_cache(istate);
> }
>
> +static int read_link(const char *path, char *buf, size_t bufsize)
> +{
> + int len;
> +
> + len = readlink(path, buf, bufsize);
> + if (len < 0 || len >= bufsize)
> + return -1;
> + buf[len] = '\0';
> + return 0;
> +}
> +
> int connect_to_index_helper(void)
> {
> struct sockaddr_un address = {0};
> int fd;
>
> - if (readlink(git_path("index-helper.path"),
> address.sun_path,
> + if (read_link(git_path("index-helper.path"),
> address.sun_path,
> sizeof(address.sun_path)) < 0)
> return -1;
>
Will squash.
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