On Sat, Feb 16, 2013 at 01:50:24AM +0000, Al Viro wrote: > On Fri, Feb 15, 2013 at 04:46:43PM -0800, Shentino wrote: > > On Fri, Feb 15, 2013 at 4:38 PM, Shentino <shent...@gmail.com> wrote: > > > On Fri, Feb 15, 2013 at 4:04 PM, Al Viro <v...@zeniv.linux.org.uk> wrote: > > >> How would you manage to have it masked at that point? setup_new_exec() > > >> is inevitable after success of flush_old_exec() and it will do > > >> flush_signal_handlers() for us. > > > > > > I wouldn't know for sure but I read somewhere that even if execve > > > resets handled signals, it didn't also say that ignored signals were > > > also reset. (Source: execve man page.) > > > > Also, apologies for the terminology mix-up. By masked, I mean that > > the signal was ignored as directed by userspace a-la signal(SIGSEGV, > > SIG_IGN). > > > > Plus I *think* that signal ignore masks are preserved across an exec. > > You are correct. OK, what it means is that we do need that force_sigsegv() - > either there or in all places in ->load_binary() where we currently have > send_sig_info(SIGSEGV). I don't think that it's an urgent hole, but yes, > it is a bug. Nice catch.
Arrgh... OK, I'm a blind idiot. These places in binfmt_elf.c currently use force_sig(), not send_sig_info(). Currently == since 2006 when somebody noticed the problem. Their counterparts in binfmt_elf_fdpic.c were *not* noticed. Anyway, that definitely means we want to do it in a single commit; the only remaining question is whether we have any problems with somebody ptracing such execve() and then poking the sucker with ptrace(); that _can_ happen with the current mainline for ELF binaries, so this is not something new. I'm low on coffee and about to crash, so I might be missing some horrible problem with it, but in this case I'm fairly sure that such a problem would be present in current mainline. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
