From nobody Mon Jun 16 17:34:36 2025 X-Original-To: dev-commits-src-all@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 4bLcZS2t3kz5yBF9; Mon, 16 Jun 2025 17:34:40 +0000 (UTC) (envelope-from cy.schubert@cschubert.com) Received: from omta003.cacentral1.a.cloudfilter.net (omta001.cacentral1.a.cloudfilter.net [3.97.99.32]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "Client", Issuer "CA" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4bLcZR5vxtz3dNw; Mon, 16 Jun 2025 17:34:39 +0000 (UTC) (envelope-from cy.schubert@cschubert.com) Authentication-Results: mx1.freebsd.org; none Received: from shw-obgw-4002a.ext.cloudfilter.net ([10.228.9.250]) by cmsmtp with ESMTPS id R5XOunkB39JM2RDjCuRpZe; Mon, 16 Jun 2025 17:34:38 +0000 Received: from spqr.komquats.com ([70.66.136.217]) by cmsmtp with ESMTPSA id RDjBu0WItl5eGRDjCuZ4JW; Mon, 16 Jun 2025 17:34:38 +0000 X-Auth-User: cschuber X-Authority-Analysis: v=2.4 cv=EO6l0EZC c=1 sm=1 tr=0 ts=685055ae a=h7br+8Ma+Xn9xscxy5znUg==:117 a=h7br+8Ma+Xn9xscxy5znUg==:17 a=kj9zAlcOel0A:10 a=6IFa9wvqVegA:10 a=6I5d2MoRAAAA:8 a=EkcXrb_YAAAA:8 a=VxmjJ2MpAAAA:8 a=YxBL1-UpAAAA:8 a=Ew9AnIkR3oUrOk5kWkAA:9 a=CjuIK1q_8ugA:10 a=LK5xJRSDVpKd5WXXoEvA:22 a=7gXAzLPJhVmCkEl4_tsf:22 a=Ia-lj3WSrqcvXOmTRaiG:22 Received: from slippy.cwsent.com (slippy [10.1.1.91]) by spqr.komquats.com (Postfix) with ESMTP id 72C10357; Mon, 16 Jun 2025 10:34:36 -0700 (PDT) Received: by slippy.cwsent.com (Postfix, from userid 1000) id 68EA7AE; Mon, 16 Jun 2025 10:34:36 -0700 (PDT) X-Mailer: exmh version 2.9.0 11/07/2018 with nmh-1.8+dev Reply-to: Cy Schubert From: Cy Schubert X-os: FreeBSD X-Sender: cy@cwsent.com X-URL: http://www.cschubert.com/ To: John Baldwin cc: Cy Schubert , src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: Re: git: bafe0e7edaee - main - pam_ksu: Proactively address MIT KRB5 build failure In-reply-to: <36939c6e-1c9f-4e55-bd42-e759e6a37a2e@FreeBSD.org> References: <202506160251.55G2plI3062868@gitrepo.freebsd.org> <36939c6e-1c9f-4e55-bd42-e759e6a37a2e@FreeBSD.org> Comments: In-reply-to John Baldwin message dated "Mon, 16 Jun 2025 12:31:54 -0400." List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-all@freebsd.org Sender: owner-dev-commits-src-all@FreeBSD.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Mon, 16 Jun 2025 10:34:36 -0700 Message-Id: <20250616173436.68EA7AE@slippy.cwsent.com> X-CMAE-Envelope: MS4xfMIqqD7VrcJzaCUF4lcL2M/M7fWXa4+GjJHlf30NpyE6LqMKK+yNcFseOY1uhKTI3yBFeI7cQ2uWyBwGjQW7e8AoTo6rqp2OAbjtwzCl6IPUmCJmYo85 R+XRTW4VwXrsWrEeSlaD56Q7L0uAXw1QxRxrOJ3mAwFF3JU/kUPrCD8SlT6019Q6TxaKgSAkCnwitAbYX6xvikM2bsYR4qR0XOz1NvI5KfKSICnEMYxl9sl6 EZsWk3kNBuoy5hvvM+vnqgtruJwr3UfYrCbURAggjVy4H9W95Sh3t9hivh52PlucKLNZmhzTu1RGB9rEdAuDVM143Vfg7Y8FbHzJWcbTMKrw0PX4rCMsXBP3 c+rEmwOL X-Rspamd-Queue-Id: 4bLcZR5vxtz3dNw X-Spamd-Bar: ---- X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN_FAIL(0.00)[32.99.97.3.asn.rspamd.com:server fail] In message <36939c6e-1c9f-4e55-bd42-e759e6a37a2e@FreeBSD.org>, John Baldwin wri tes: > On 6/15/25 22:51, Cy Schubert wrote: > > The branch main has been updated by cy: > > > > URL: https://cgit.FreeBSD.org/src/commit/?id=bafe0e7edaee75f3fcfe6bf6c3e7b1 > e816361365 > > > > commit bafe0e7edaee75f3fcfe6bf6c3e7b1e816361365 > > Author: Cy Schubert > > AuthorDate: 2025-06-05 17:09:57 +0000 > > Commit: Cy Schubert > > CommitDate: 2025-06-16 02:49:35 +0000 > > > > pam_ksu: Proactively address MIT KRB5 build failure > > > > MIT KRB5 does not provide a krb5_make_principal() function. We need to > > provide this ourselves for now. We provide the function for now while > > MIT and Heimdal are both in the tree. When Heimdal is removed we can > > inline the calls to krb5_get_default_realm() and > > krb5_build_principal_va(). krb5_build_principal_va() is > > deprecated in MIT KRB5. Its replacement, krb5_build_principal_alloc_va > () > > will be used instead at that time. > > > > Sponsored by: The FreeBSD Foundation > > Differential revision: https://reviews.freebsd.org/D50808 > > I still don't understand how this can work instead of instantly segfaulting > as I said in the review. > > > diff --git a/lib/libpam/modules/pam_ksu/pam_ksu.c b/lib/libpam/modules/pam_ > ksu/pam_ksu.c > > index 47362c835c12..a6b3f043d3f4 100644 > > --- a/lib/libpam/modules/pam_ksu/pam_ksu.c > > +++ b/lib/libpam/modules/pam_ksu/pam_ksu.c > > @@ -48,6 +48,61 @@ static long get_su_principal(krb5_context, const ch > ar *, const char *, > > static int auth_krb5(pam_handle_t *, krb5_context, const char *, > > krb5_principal); > > > > +#ifdef MK_MITKRB5 > > +/* For MIT KRB5 only. */ > > + > > +/* > > + * XXX This entire module will need to be rewritten when heimdal > > + * XXX compatidibility is no longer needed. > > + */ > > +#define KRB5_DEFAULT_CCFILE_ROOT "/tmp/krb5cc_" > > +#define KRB5_DEFAULT_CCROOT "FILE:" KRB5_DEFAULT_CCFILE_ROOT > > + > > +/* > > + * XXX We will replace krb5_build_principal_va() with > > + * XXX krb5_build_principal_alloc_va() when Heimdal is finally > > + * XXX removed. > > + */ > > +krb5_error_code KRB5_CALLCONV > > +krb5_build_principal_va(krb5_context context, > > + krb5_principal princ, > > + unsigned int rlen, > > + const char *realm, > > + va_list ap); > > +typedef char *heim_general_string; > > +typedef heim_general_string Realm; > > +typedef Realm krb5_realm; > > +typedef const char *krb5_const_realm; > > + > > +static krb5_error_code > > +krb5_make_principal(krb5_context context, krb5_principal principal, > > + krb5_const_realm realm, ...) > > +{ > > + krb5_error_code rc; > > + va_list ap; > > + if (realm == NULL) { > > + krb5_realm temp_realm = NULL; > > + if ((rc = krb5_get_default_realm(context, &temp_realm))) > > + return (rc); > > + realm=temp_realm; > > + if (temp_realm) > > + free(temp_realm); > > + } > > + va_start(ap, realm); > > + /* > > + * XXX Ideally we should be using krb5_build_principal_alloc_va() > > + * XXX here because krb5_build_principal_va() is deprecated. But, > > + * XXX this would require changes elsewhere in the calling code > > + * XXX to call krb5_free_principal() elsewhere to free the > > + * XXX principal. We can do that after Heimdal is removed from > > + * XXX our tree. > > + */ > > + rc = krb5_build_principal_va(context, principal, strlen(realm), realm, > ap); > > + va_end(ap); > > + return (rc); > > +} > > +#endif > > + > > PAM_EXTERN int > > pam_sm_authenticate(pam_handle_t *pamh, int flags __unused, > > int argc __unused, const char *argv[] __unused) > > @@ -217,7 +272,13 @@ get_su_principal(krb5_context context, const char *tar > get_user, const char *curr > > if (rv != 0) > > return (errno); > > if (default_principal == NULL) { > > +#ifdef MK_MITKRB5 > > + /* For MIT KRB5. */ > > + rv = krb5_make_principal(context, default_principal, NULL, curr > ent_user, NULL); > > +#else > > + /* For Heimdal. */ > > rv = krb5_make_principal(context, &default_principal, NULL, cur > rent_user, NULL); > > +#endif > > At this point default_principal is always NULL, so you pass in a NULL pointer > to > krb5_build_princpal_va. That will surely crash. In Heimdal the principal argument is defined as krb5_principal *principal Whereas in MIT the principal argument is krb5_principal princ In Heimdal krb5_principal is a structure. In MIT it is a pointer to the same structure. build_principal() is defined as a struct in Heimdal and a pointer to a struct in MIT. Therefore the function prototypes are different. > > Also, you then pass that NULL pointer to the following code which would also > surely crash: > > /* Now that we have some principal, if the target account is > * `root', then transform it into a `root' instance, e.g. > * `user@REA.LM' -> `user/root@REA.LM'. > */ > rv = krb5_unparse_name(context, default_principal, &principal_name); > krb5_free_principal(context, default_principal); > > This is why I said your comment seems wrong. The Heimdal version is clearly > allocating > a principal, so the MIT version should also be doing that, and you should alr > eady be > using krb5_build_prinpcial_alloc_va() _now_. Your comment claims that the ca > lling code > isn't using krb5_free_principal(), but the calling code quoted above in get_s > u_principal() > does call krb5_free_principal(). > > Have you tested this at runtime? Yes. It is running here. slippy$ which ksu /usr/bin/ksu slippy$ /usr/bin/ksu Authenticated cy@CWSENT.COM Account root: authorization for cy@CWSENT.COM successful Changing uid to root (0) slippy$ id uid=0(root) gid=0(wheel) groups=0(wheel),5(operator),920(vboxusers) slippy$ -- Cheers, Cy Schubert FreeBSD UNIX: Web: https://FreeBSD.org NTP: Web: https://nwtime.org e**(i*pi)+1=0