[pacman-dev] [PATCH] BUG: Fix realloc of 0 bytes

[Allan McRae]

On 19/12/14 20:11, tredaelli at archlinux.info wrote:
> From: Timothy Redaelli <timothy.redaelli at gmail.com>
> 
> realloc with size == 0 can return NULL, and passing NULL to qsort will
> cause a SEGFAULT (CERT MEM04-C)

If there are no files, pacman will never enter this part of the code.

> ---
>  lib/libalpm/be_local.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/lib/libalpm/be_local.c b/lib/libalpm/be_local.c
> index 93763966..a734eba3 100644
> --- a/lib/libalpm/be_local.c
> +++ b/lib/libalpm/be_local.c
> @@ -790,6 +790,9 @@ static int local_db_read(alpm_pkg_t *info, alpm_dbinfrq_t inforeq)
>  					memcpy(files[files_count].name, line, len);
>  					files_count++;
>  				}
> +				if (files_count == 0) {
> +					continue;
> +				}
>  				/* attempt to hand back any memory we don't need */
>  				files = realloc(files, sizeof(alpm_file_t) * files_count);
>  				/* make sure the list is sorted */
>