Date: Thu, 13 Feb 2020 13:29:50 -0500 From: Rich Felker <dalias@...c.org> To: musl@...ts.openwall.com Subject: Re: execvp() behaviour with unrecognized file header On Thu, Feb 13, 2020 at 11:02:08AM +0100, Micha Nelissen wrote: > On 12-02-2020 15:27, Rich Felker wrote: > >> Since this is non-conformant to POSIX, Adélie integrated quinq's patch: > >> https://code.foxkit.us/adelie/musl/commit/16cbbea8e97d08e0fc6e9ccda0cf8b6e87ed6b82 > > > > Note that this patch has multiple problems which is why it's not > > For execlp, what about 'return execvp("/bin/sh", &file);' in case of > ENOEXEC? Too ugly? Assumes right-to-left push order with top-down stack > (or left-to-right in case of bottom-up stack). This doesn't work -- even if you ignore UB and assume some simplistic "high level asm" model of C. There is a clean solution for execlp, just expanding the VLA by a couple slots (VLA can be assumed reasonable size since the same number of args were passed in to execlp and since the number is a fixed compile-time constant the programmer has decided to use rather than potentially variable) and prepending to the VLA if needed... > Doesn't work for execvp itself though. ...but regardless execvp needs a solution too, and execlp can just piggyback on whatever execvp does, so there's really no reason to be writing a specialized version of this functionality for execlp. Rich
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.