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pam_namespace: protect_dir(): use O_DIRECTORY to prevent local DoS

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situations. CVE-2024-22365

Resolves: RHEL-21242

Signed-off-by: Iker Pedrosa <ipedrosa@redhat.com>
This commit is contained in:
Iker Pedrosa 2024-02-12 15:43:10 +01:00
parent b108df3047
commit b214c5305b
2 changed files with 66 additions and 1 deletions
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58
pam-1.3.1-namespace-protect-dir.patch Normal file
View File

@ -0,0 +1,58 @@
From 031bb5a5d0d950253b68138b498dc93be69a64cb Mon Sep 17 00:00:00 2001
From: Matthias Gerstner <matthias.gerstner@suse.de>
Date: Wed, 27 Dec 2023 14:01:59 +0100
Subject: [PATCH] pam_namespace: protect_dir(): use O_DIRECTORY to prevent
local DoS situations
Without O_DIRECTORY the path crawling logic is subject to e.g. FIFOs
being placed in user controlled directories, causing the PAM module to
block indefinitely during `openat()`.
Pass O_DIRECTORY to cause the `openat()` to fail if the path does not
refer to a directory.
With this the check whether the final path element is a directory
becomes unnecessary, drop it.
---
modules/pam_namespace/pam_namespace.c | 18 +-----------------
1 file changed, 1 insertion(+), 17 deletions(-)
diff --git a/modules/pam_namespace/pam_namespace.c b/modules/pam_namespace/pam_namespace.c
index 2528cff8..f72d6718 100644
--- a/modules/pam_namespace/pam_namespace.c
+++ b/modules/pam_namespace/pam_namespace.c
@@ -1201,7 +1201,7 @@ static int protect_dir(const char *path, mode_t mode, int do_mkdir,
int dfd = AT_FDCWD;
int dfd_next;
int save_errno;
- int flags = O_RDONLY;
+ int flags = O_RDONLY | O_DIRECTORY;
int rv = -1;
struct stat st;
@@ -1255,22 +1255,6 @@ static int protect_dir(const char *path, mode_t mode, int do_mkdir,
rv = openat(dfd, dir, flags);
}
- if (rv != -1) {
- if (fstat(rv, &st) != 0) {
- save_errno = errno;
- close(rv);
- rv = -1;
- errno = save_errno;
- goto error;
- }
- if (!S_ISDIR(st.st_mode)) {
- close(rv);
- errno = ENOTDIR;
- rv = -1;
- goto error;
- }
- }
-
if (flags & O_NOFOLLOW) {
/* we are inside user-owned dir - protect */
if (protect_mount(rv, p, idata) == -1) {
--
2.43.0

9
pam.spec
View File

@ -3,7 +3,7 @@
Summary: An extensible library which provides authentication for applications
Name: pam
Version: 1.3.1
Release: 32%{?dist}
Release: 33%{?dist}
# The library is BSD licensed with option to relicense as GPLv2+
# - this option is redundant as the BSD license allows that anyway.
# pam_timestamp, pam_loginuid, and pam_console modules are GPLv2+.
@ -108,6 +108,8 @@ Patch67: pam-1.3.1-unix-default-rounds.patch
Patch68: pam-1.3.1-faillock-create-tallydir.patch
# https://github.com/linux-pam/linux-pam/commit/23393bef92c1e768eda329813d7af55481c6ca9f
Patch69: pam-1.3.1-access-handle-hostnames.patch
# https://github.com/linux-pam/linux-pam/commit/031bb5a5d0d950253b68138b498dc93be69a64cb
Patch70: pam-1.3.1-namespace-protect-dir.patch
%define _pamlibdir %{_libdir}
%define _moduledir %{_libdir}/security
@ -225,6 +227,7 @@ cp %{SOURCE18} .
%patch67 -p1 -b .unix-default-rounds
%patch68 -p1 -b .faillock-create-tallydir
%patch69 -p1 -b .access-handle-hostnames
%patch70 -p1 -b .namespace-protect-dir
autoreconf -i
@ -478,6 +481,10 @@ done
%doc doc/specs/rfc86.0.txt
%changelog
* Mon Feb 12 2024 Iker Pedrosa <ipedrosa@redhat.com> - 1.3.1-33
- pam_namespace: protect_dir(): use O_DIRECTORY to prevent local DoS
situations. CVE-2024-22365. Resolves: RHEL-21242
* Fri Jan 26 2024 Iker Pedrosa <ipedrosa@redhat.com> - 1.3.1-32
- pam_access: handle hostnames in access.conf. Resolves: RHEL-3374