[lxc-devel] [PATCH 1/6] fix integer overflow in setproctitle
Serge Hallyn
serge.hallyn at ubuntu.com
Mon Apr 13 19:05:24 UTC 2015
Quoting Tycho Andersen (tycho.andersen at canonical.com):
> 1. prctl() only accepts longs, so we can just scan the stat file as longs.
? That's not what the manpage tells me.
> 2. check overflow before addition
>
> Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
> ---
> src/lxc/utils.c | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/src/lxc/utils.c b/src/lxc/utils.c
> index 1df6e8f..cc12ecd 100644
> --- a/src/lxc/utils.c
> +++ b/src/lxc/utils.c
> @@ -1599,7 +1599,7 @@ int setproctitle(char *title)
> char buf[2048], *tmp;
> FILE *f;
> int i, len, ret = 0;
> - unsigned long arg_start, arg_end, env_start, env_end;
> + long arg_start, arg_end, env_start, env_end;
>
> f = fopen_cloexec("/proc/self/stat", "r");
> if (!f) {
> @@ -1624,7 +1624,7 @@ int setproctitle(char *title)
> if (!tmp)
> return -1;
>
> - i = sscanf(tmp, "%lu %lu %lu %lu", &arg_start, &arg_end, &env_start, &env_end);
> + i = sscanf(tmp, "%ld %ld %ld %ld", &arg_start, &arg_end, &env_start, &env_end);
> if (i != 4) {
> return -1;
> }
> @@ -1644,15 +1644,21 @@ int setproctitle(char *title)
> if (len >= arg_end - arg_start) {
> env_start = env_end;
> }
> +
> + /* check overflow */
> + if (arg_start + len < 0) {
> + return -1;
> + }
> +
> arg_end = arg_start + len;
> }
>
> strcpy((char*)arg_start, title);
>
> - ret |= prctl(PR_SET_MM, PR_SET_MM_ARG_START, (long)arg_start, 0, 0);
> - ret |= prctl(PR_SET_MM, PR_SET_MM_ARG_END, (long)arg_end, 0, 0);
> - ret |= prctl(PR_SET_MM, PR_SET_MM_ENV_START, (long)env_start, 0, 0);
> - ret |= prctl(PR_SET_MM, PR_SET_MM_ENV_END, (long)env_end, 0, 0);
> + ret |= prctl(PR_SET_MM, PR_SET_MM_ARG_START, arg_start, 0, 0);
> + ret |= prctl(PR_SET_MM, PR_SET_MM_ARG_END, arg_end, 0, 0);
> + ret |= prctl(PR_SET_MM, PR_SET_MM_ENV_START, env_start, 0, 0);
> + ret |= prctl(PR_SET_MM, PR_SET_MM_ENV_END, env_end, 0, 0);
>
> return ret;
> }
> --
> 2.1.4
>
> _______________________________________________
> lxc-devel mailing list
> lxc-devel at lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-devel
More information about the lxc-devel
mailing list