[Spice-devel] [PATCH spice-server 1/2] stat-file: Fix off by one buffer overflow

[Jonathon Jongsma]

Acked-by: Jonathon Jongsma <jjongsma at redhat.com>

Out of curiosity, how did you find it? Just reading code?



On Thu, 2017-02-02 at 12:46 +0000, Frediano Ziglio wrote:
> The stat file contains an array of max_nodes elements
> so we must stay in [0, max_nodes) range, not [0, max_nodes].
> 
> There are no spice path that lead to these overflows but
> it's better to have them fixed before creating one.
> 
> Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
> ---
>  server/stat-file.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/server/stat-file.c b/server/stat-file.c
> index c23f4f5..3fe3890 100644
> --- a/server/stat-file.c
> +++ b/server/stat-file.c
> @@ -168,7 +168,7 @@ stat_file_add_node(RedStatFile *stat_file,
> StatNodeRef parent, const char *name,
>      }
>      stat_file->stat->generation++;
>      stat_file->stat->num_of_nodes++;
> -    for (ref = 0; ref <= stat_file->max_nodes; ref++) {
> +    for (ref = 0; ref < stat_file->max_nodes; ref++) {
>          node = &stat_file->stat->nodes[ref];
>          if (!(node->flags & SPICE_STAT_NODE_FLAG_ENABLED)) {
>              break;
> @@ -211,7 +211,7 @@ static void stat_file_remove(RedStatFile
> *stat_file, SpiceStatNode *node)
>      /* children will be orphans */
>      if (stat_file->stat->root_index == node_ref) {
>          stat_file->stat->root_index = node_next;
> -    } else for (ref = 0; ref <= stat_file->max_nodes; ref++) {
> +    } else for (ref = 0; ref < stat_file->max_nodes; ref++) {
>          node = &stat_file->stat->nodes[ref];
>          if (!(node->flags & SPICE_STAT_NODE_FLAG_ENABLED)) {
>              continue;