On Mon, Apr 13, 2015 at 07:05:24PM +0000, Serge Hallyn wrote:
> Quoting Tycho Andersen (tycho.ander...@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.
Hmm, yeah, I must be crazy. I'm not sure why the casts were in there
before then. I'll send a different patch.
Tycho
> > 2. check overflow before addition
> >
> > Signed-off-by: Tycho Andersen <tycho.ander...@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@lists.linuxcontainers.org
> > http://lists.linuxcontainers.org/listinfo/lxc-devel
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