Re: git: 98f18cd98824 - main - pam_ksu: Move the realm free to end of function
Date: Mon, 16 Jun 2025 18:46:08 UTC
On Mon, Jun 16, 2025 at 06:42:41PM +0000, Cy Schubert wrote: > The branch main has been updated by cy: > > URL: https://cgit.FreeBSD.org/src/commit/?id=98f18cd98824acdf1045e74615f2db0219019f0b > > commit 98f18cd98824acdf1045e74615f2db0219019f0b > Author: Cy Schubert <cy@FreeBSD.org> > AuthorDate: 2025-06-16 18:40:51 +0000 > Commit: Cy Schubert <cy@FreeBSD.org> > CommitDate: 2025-06-16 18:42:30 +0000 > > pam_ksu: Move the realm free to end of function > > This avoids a use after free. > > Noted by: jhb > --- > lib/libpam/modules/pam_ksu/pam_ksu.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/lib/libpam/modules/pam_ksu/pam_ksu.c b/lib/libpam/modules/pam_ksu/pam_ksu.c > index a6b3f043d3f4..e50c3e387311 100644 > --- a/lib/libpam/modules/pam_ksu/pam_ksu.c > +++ b/lib/libpam/modules/pam_ksu/pam_ksu.c > @@ -85,8 +85,6 @@ krb5_make_principal(krb5_context context, krb5_principal principal, > if ((rc = krb5_get_default_realm(context, &temp_realm))) > return (rc); > realm=temp_realm; > - if (temp_realm) > - free(temp_realm); > } > va_start(ap, realm); > /* > @@ -99,6 +97,8 @@ krb5_make_principal(krb5_context context, krb5_principal principal, > */ > rc = krb5_build_principal_va(context, principal, strlen(realm), realm, ap); > va_end(ap); > + if (temp_realm) > + free(temp_realm); Hey Cy, I think the call to free can be made unconditional as it's safe to call free on a NULL pointer (which turns into a no-op). Thanks, -- Shawn Webb Cofounder / Security Engineer HardenedBSD Signal Username: shawn_webb.74 Tor-ified Signal: +1 303-901-1600 / shawn_webb_opsec.50 https://git.hardenedbsd.org/hardenedbsd/pubkeys/-/raw/master/Shawn_Webb/03A4CBEBB82EA5A67D9F3853FF2E67A277F8E1FA.pub.asc