Re: [PATCH] src/ext4_resize.c: set errno to 0 before the strtoull call

["Andrew G. Morgan" <morgan@kernel.org>]

Thanks for finding this.

Fixed in:

https://git.kernel.org/pub/scm/libs/libcap/libcap.git/commit/?id=f25a1b7e69f7b33e6afb58b3e38f3450b7d2d9a0

Cheers

Andrew

On Wed, Jan 19, 2022 at 6:08 AM Cristian Rodríguez
<crrodriguez@opensuse.org> wrote:
>
> On Wed, Jan 19, 2022 at 10:57 AM Cristian Rodríguez
> <crrodriguez@opensuse.org> wrote:
>
> > This is not a glibc problem though, looks like lcap is clobbering
> > errno. I'd bet good CLP on the code called in
> > __attribute__((constructor (300))) static void _initialize_libcap(void) .
> > I strongly suggest not to use constructors on shared libraries unless
> > all the components using the library are in your control and you are
> > sure constructors will not ruin some other application's day.
>
> __attribute__((constructor (300))) static void _initialize_libcap(void)
> {
>     if (_cap_max_bits) {
>         return;
>     }
>     cap_set_syscall(NULL, NULL);  --> nope
>     _binary_search(_cap_max_bits, cap_get_bound, 0, __CAP_MAXBITS,
> __CAP_BITS); --> 🤔
>     cap_proc_root("/proc");
> }
>
> do, what cap_get_bound does ?
>
> int cap_get_bound(cap_value_t cap)
> {
>     int result;
>
>     result = prctl(PR_CAPBSET_READ, pr_arg(cap), pr_arg(0));
>     if (result < 0) {
>         errno = -result; --> If all my bets paid , I would be rich..
> here is your 1
>         return -1;
>     }
>     return result;
> }