On 03/05/2018 05:58 PM, Nicolas Iooss wrote:
> clang's static analyzer reports an out-of-bound array access in
> semanage_user_roles() when num_roles is zero, with the following
> statement:
>
> strcpy(roles,roles_arr[0]);
>
> When num_roles is zero, roles_arr[0] is not uninitialized and roles is
> the result of malloc(0) so this strcpy is dangerous. Make
> semanage_user_roles() return an empty string instead.
>
> Signed-off-by: Nicolas Iooss <nicolas.iooss@xxxxxxx>
Acked-by: Stephen Smalley <sds@xxxxxxxxxxxxx>
> ---
> libsemanage/src/seusers_local.c | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/libsemanage/src/seusers_local.c b/libsemanage/src/seusers_local.c
> index 42c3a8b662c2..413ebdddeb34 100644
> --- a/libsemanage/src/seusers_local.c
> +++ b/libsemanage/src/seusers_local.c
> @@ -35,12 +35,16 @@ static char *semanage_user_roles(semanage_handle_t * handle, const char *sename)
> for (i = 0; i<num_roles; i++) {
> size += (strlen(roles_arr[i]) + 1);
> }
> - roles = malloc(size);
> - if (roles) {
> - strcpy(roles,roles_arr[0]);
> - for (i = 1; i<num_roles; i++) {
> - strcat(roles,",");
> - strcat(roles,roles_arr[i]);
> + if (num_roles == 0) {
> + roles = strdup("");
> + } else {
> + roles = malloc(size);
> + if (roles) {
> + strcpy(roles,roles_arr[0]);
> + for (i = 1; i<num_roles; i++) {
> + strcat(roles,",");
> + strcat(roles,roles_arr[i]);
> + }
> }
> }
> }
>
