From nobody Wed Nov 3 10:18:49 2021 X-Original-To: bugs@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 77F161846926 for ; Wed, 3 Nov 2021 10:18:49 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4HkjRF2vDKz4clS for ; Wed, 3 Nov 2021 10:18:49 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 43BAC16E2D for ; Wed, 3 Nov 2021 10:18:49 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.5]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id 1A3AInoE094796 for ; Wed, 3 Nov 2021 10:18:49 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 1A3AInYq094795 for bugs@FreeBSD.org; Wed, 3 Nov 2021 10:18:49 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 259625] fexecve interacts incorrectly with interpreters Date: Wed, 03 Nov 2021 10:18:49 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 13.0-RELEASE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: sir@cmpwn.com X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated List-Id: Bug reports List-Archive: https://lists.freebsd.org/archives/freebsd-bugs List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-bugs@freebsd.org MIME-Version: 1.0 X-ThisMailContainsUnwantedMimeParts: N https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D259625 Bug ID: 259625 Summary: fexecve interacts incorrectly with interpreters Product: Base System Version: 13.0-RELEASE Hardware: amd64 OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: sir@cmpwn.com This problem seems to be reproducible in FreeBSD 13. Given the following test program: #include #include extern char **environ; int main(void) { int fd =3D open("./test.sh", O_RDONLY); char *argv[] =3D { "./test.sh", NULL }; fexecve(fd, argv, environ); } And the following ./test.sh: #!/bin/sh echo hi The result is: /bin/sh: cannot open /dev/fd/3: No such file or directory Mounting fdescfs on /dev/fd changes the error: /bin/sh: cannot open /dev/fd/3: Permission denied The results do not change with O_EXEC instead of (or in addition to) O_RDON= LY. Possibly related: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D169651 It seems like this may have worked at some point, as some effort seems to h= ave gone into making this use-case work. The fdescfs requirement is documented = in the CAVEATS section of the execve(2) man page, but it does not seem to work even with fdescfs. I think it would also be wise for FreeBSD to enable fdes= cfs by default in order to allow programs to reliably depend on the functionali= ty of fexecve. --=20 You are receiving this mail because: You are the assignee for the bug.=