From mboxrd@z Thu Jan  1 00:00:00 1970
X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/14756
Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail
From: Joshua Hudson <joshudson@gmail.com>
Newsgroups: gmane.linux.lib.musl.general
Subject: Re: Hangup calling setuid() from vfork() child
Date: Mon, 30 Sep 2019 12:57:34 -0700
Message-ID: <CA+jjjYSomVyXPoRkioRj3yhS6xRZ+Ejv9xpm8_ALdJLuD3o=Nw@mail.gmail.com>
Reply-To: musl@lists.openwall.com
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226";
	logging-data="237345"; mail-complaints-to="usenet@blaine.gmane.org"
To: musl <musl@lists.openwall.com>
Original-X-From: musl-return-14772-gllmg-musl=m.gmane.org@lists.openwall.com Mon Sep 30 21:57:50 2019
Return-path: <musl-return-14772-gllmg-musl=m.gmane.org@lists.openwall.com>
Envelope-to: gllmg-musl@m.gmane.org
Original-Received: from mother.openwall.net ([195.42.179.200])
	by blaine.gmane.org with smtp (Exim 4.89)
	(envelope-from <musl-return-14772-gllmg-musl=m.gmane.org@lists.openwall.com>)
	id 1iF1nq-000zcr-3W
	for gllmg-musl@m.gmane.org; Mon, 30 Sep 2019 21:57:50 +0200
Original-Received: (qmail 9800 invoked by uid 550); 30 Sep 2019 19:57:47 -0000
Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm
Precedence: bulk
List-Post: <mailto:musl@lists.openwall.com>
List-Help: <mailto:musl-help@lists.openwall.com>
List-Unsubscribe: <mailto:musl-unsubscribe@lists.openwall.com>
List-Subscribe: <mailto:musl-subscribe@lists.openwall.com>
List-ID: <musl.lists.openwall.com>
Original-Received: (qmail 9768 invoked from network); 30 Sep 2019 19:57:46 -0000
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=gmail.com; s=20161025;
        h=mime-version:from:date:message-id:subject:to;
        bh=PQZufclII4Hv6f135CoL3xk13yP7nqieYfqSERyqBaY=;
        b=qpj4k12Mv0FupUBoyYRDcDE4OscJar8W+q6kSACLl/UZDV8AgqD64lR8cS6hZBZWp+
         AnhavPV7k+mm2iI0gSElfKr89GGQ4SKgdJ2J21sbvGxfzP78DF1MGlkTgQsC9vYmTh0c
         ULy8lDf48WRR/EYMOCJr8U7u5aoFDJKZkqgP7cwMoGlok8rh5refSdFSoUYncgzAtYIw
         Hrw9+1zGzvV2kuVeyOv73KBRDpXPsFoPpziMFroqMt4DH0gbF1fNaOGBTt11twgZf2qk
         bpRhbL8IzluYWKceiKPDsDN2BSMxAnbvRfhVKKajLCCCWRXZH2uQW/FAbnKbnyD51tWX
         Ak7w==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=1e100.net; s=20161025;
        h=x-gm-message-state:mime-version:from:date:message-id:subject:to;
        bh=PQZufclII4Hv6f135CoL3xk13yP7nqieYfqSERyqBaY=;
        b=j/CZWAMcyGI1G1zKm6krp8URUm3gyJySJoWwLa2HeLC+cYgeM7NgqicbeaIbiCtSSX
         YcvUFOBs+ijXkiqW9HSjSCoIKgfaYwvkCiKn6W6Xa3KgUk8NIwqIV5cb2Di761ZSEzHi
         jRoRZQ8+MvlstDREM2RjXafm0kr3d8oilyrJfxj42MGY3O3+b6sB6/6TxFdsFzWt6Y20
         wieQkXKKUUYxKsZVE8Xdq84D9VA1j96m3q3aIlxFuqZWAgRpDQ26tSRbcM6X02cWtUP/
         OfMonSMHU1U/V4wXWrfoM7QFTTg6F+1n1ANt09JhjWm/0WmuYLGWiMGMlR6Db2Ty3PLv
         uZpQ==
X-Gm-Message-State: APjAAAVugZr3UsJhUZd3/RAa29Js6p5giJteEHqwxMPKlG3kLDvwVK1B
	MWAs8KMYYeR+uRBOVotymuprXApIIbSEE1RR9dLxwg==
X-Google-Smtp-Source: APXvYqzjYQUUfrdJecjSTwjR02/YxnVlOcG/r3swsBpj+rXCHEmYOTl5wAfzVJLKmuJfPGZgnNPMFVgF8hDUJhFWTsM=
X-Received: by 2002:a05:6102:516:: with SMTP id l22mr10408249vsa.168.1569873454530;
 Mon, 30 Sep 2019 12:57:34 -0700 (PDT)
Xref: news.gmane.org gmane.linux.lib.musl.general:14756
Archived-At: <http://permalink.gmane.org/gmane.linux.lib.musl.general/14756>

>It's simpler than that. The (retired) specification for vfork did not
>allow anything but _exit or execve in the child after vfork, so the
>issue doesn't arise and it works perfectly fine with threads as long
>as you follow the requirement.

I'm reading the man page for vfork and it says what it actually does, that
is overlay the child process on the memory of the calling process.

posix_spawn can't be used in the originating location, and fork() is
hogging too much memory.