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Bug#1029121: marked as done (bullseye-pu: package lxc/4.0.6-2+deb11u2)

Your message dated Sat, 29 Apr 2023 10:54:14 +0100
with message-id <502b8fb37ece620c9723446611a9287974ba5a0c.camel@adam-barratt.org.uk>
and subject line Closing p-u requests for fixes included in 11.7
has caused the Debian Bug report #1029121,
regarding bullseye-pu: package lxc/4.0.6-2+deb11u2
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what this
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-- 
1029121: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1029121
Debian Bug Tracking System
Contact owner@bugs.debian.org with problems
--- Begin Message --- 
Package: release.debian.org
Severity: normal
Tags: bullseye
User: release.debian.org@packages.debian.org
Usertags: pu
X-Debbugs-Cc: pkg-lxc-devel@lists.alioth.debian.org, gibmat@debian.org
Control: affects -1 + src:lxc

[ Reason ]
The version of lxc in bullseye is affected by the low-severity
CVE-2022-47952 which was fixed in the recent release of lxc 5.0.2
(uploaded to unstable yesterday). As the fix was trivial to apply to
the version of lxc in bullseye, I think it would be beneficial to
include it in the next point release.

[ Impact ]
Affected versions of lxc suffer a minor information leak which allows a
local user to infer whether any file exists, even within a protected
directory tree.

[ Tests ]
A manual proof-of-concept test is provided in the upstream commit
fixing this issue.

[ Risks ]
There are no changes to any of the logic of lxc; the error messages
which are returned are modified to be identical in every error case,
preventing the information leak.

[ Checklist ]
  [*] *all* changes are documented in the d/changelog
  [*] I reviewed all changes and I approve them
  [*] attach debdiff against the package in (old)stable
  [*] the issue is verified as fixed in unstable

[ Changes ]
Backport upstream commit 1b0469530d7a38b8f8990e114b52530d1bf7f3b8,
which fixes CVE-2022-47952. (The line numbers in the diff shifted
slightly, otherwise no changes to the patch.)

[ Other info ]
The source debdiff is attached.

diff -Nru lxc-4.0.6/debian/changelog lxc-4.0.6/debian/changelog
--- lxc-4.0.6/debian/changelog	2022-01-13 19:57:39.000000000 +0000
+++ lxc-4.0.6/debian/changelog	2023-01-18 02:53:46.000000000 +0000
@@ -1,3 +1,9 @@
+lxc (1:4.0.6-2+deb11u2) bullseye; urgency=medium
+
+  * Backport fix for CVE-2022-47952
+
+ -- Mathias Gibbens <gibmat@debian.org>  Wed, 18 Jan 2023 02:53:46 +0000
+
 lxc (1:4.0.6-2+deb11u1) bullseye; urgency=medium
 
   * lxc-download: Switch GPG server.
diff -Nru lxc-4.0.6/debian/patches/fix-CVE-2022-47952.patch lxc-4.0.6/debian/patches/fix-CVE-2022-47952.patch
--- lxc-4.0.6/debian/patches/fix-CVE-2022-47952.patch	1970-01-01 00:00:00.000000000 +0000
+++ lxc-4.0.6/debian/patches/fix-CVE-2022-47952.patch	2023-01-18 02:53:23.000000000 +0000
@@ -0,0 +1,69 @@
+From 1b0469530d7a38b8f8990e114b52530d1bf7f3b8 Mon Sep 17 00:00:00 2001
+From: Maher Azzouzi <maherazz04@gmail.com>
+Date: Sun, 25 Dec 2022 13:50:25 +0100
+Subject: [PATCH] Patching an incoming CVE (CVE-2022-47952)
+
+lxc-user-nic in lxc through 5.0.1 is installed setuid root, and may
+allow local users to infer whether any file exists, even within a
+protected directory tree, because "Failed to open" often indicates
+that a file does not exist, whereas "does not refer to a network
+namespace path" often indicates that a file exists. NOTE: this is
+different from CVE-2018-6556 because the CVE-2018-6556 fix design was
+based on the premise that "we will report back to the user that the
+open() failed but the user has no way of knowing why it failed";
+however, in many realistic cases, there are no plausible reasons for
+failing except that the file does not exist.
+
+PoC:
+> % ls /l
+> ls: cannot open directory '/l': Permission denied
+> % /usr/lib/x86_64-linux-gnu/lxc/lxc-user-nic delete lol lol /l/h/tt h h
+> cmd/lxc_user_nic.c: 1096: main: Failed to open "/l/h/tt" <----- file does not exist.
+> % /usr/lib/x86_64-linux-gnu/lxc/lxc-user-nic delete lol lol /l/h/t h h
+> cmd/lxc_user_nic.c: 1101: main: Path "/l/h/t" does not refer to a network namespace path <---- file exist!
+
+Signed-off-by: MaherAzzouzi <maherazz04@gmail.com>
+Acked-by: Serge Hallyn <serge@hallyn.com>
+---
+ src/lxc/cmd/lxc_user_nic.c | 15 ++++++---------
+ 1 file changed, 6 insertions(+), 9 deletions(-)
+
+diff --git a/src/lxc/cmd/lxc_user_nic.c b/src/lxc/cmd/lxc_user_nic.c
+index a91e2259d5..69bc6f17d1 100644
+--- a/src/lxc/cmd/lxc_user_nic.c
++++ b/src/lxc/cmd/lxc_user_nic.c
+@@ -1088,20 +1088,17 @@ int main(int argc, char *argv[])
+ 	} else if (request == LXC_USERNIC_DELETE) {
+ 		char opath[LXC_PROC_PID_FD_LEN];
+ 
+-		/* Open the path with O_PATH which will not trigger an actual
+-		 * open(). Don't report an errno to the caller to not leak
+-		 * information whether the path exists or not.
+-		 * When stracing setuid is stripped so this is not a concern
+-		 * either.
+-		 */
++		// Keep in mind CVE-2022-47952: It's crucial not to leak any
++		// information whether open() succeeded of failed.
++
+ 		netns_fd = open(args.pid, O_PATH | O_CLOEXEC);
+ 		if (netns_fd < 0) {
+-			usernic_error("Failed to open \"%s\"\n", args.pid);
++			usernic_error("Failed while opening netns file for \"%s\"\n", args.pid);
+ 			_exit(EXIT_FAILURE);
+ 		}
+ 
+ 		if (!fhas_fs_type(netns_fd, NSFS_MAGIC)) {
+-			usernic_error("Path \"%s\" does not refer to a network namespace path\n", args.pid);
++			usernic_error("Failed while opening netns file for \"%s\"\n", args.pid);
+ 			close(netns_fd);
+ 			_exit(EXIT_FAILURE);
+ 		}
+@@ -1115,7 +1112,7 @@ int main(int argc, char *argv[])
+ 		/* Now get an fd that we can use in setns() calls. */
+ 		ret = open(opath, O_RDONLY | O_CLOEXEC);
+ 		if (ret < 0) {
+-			CMD_SYSERROR("Failed to open \"%s\"\n", args.pid);
++			CMD_SYSERROR("Failed while opening netns file for \"%s\"\n", args.pid);
+ 			close(netns_fd);
+ 			_exit(EXIT_FAILURE);
+ 		}
diff -Nru lxc-4.0.6/debian/patches/series lxc-4.0.6/debian/patches/series
--- lxc-4.0.6/debian/patches/series	2022-01-13 19:57:39.000000000 +0000
+++ lxc-4.0.6/debian/patches/series	2023-01-18 02:52:02.000000000 +0000
@@ -3,3 +3,4 @@
 0006-lxc.pc.in-removes-DLOG_LIBS-which-is-not-expanded-up.patch
 0007-conf-fix-containers-retaining-CAP_NET_ADMIN.patch
 0005-lxc-download-Switch-GPG-server.patch
+fix-CVE-2022-47952.patch

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--- End Message ---
--- Begin Message --- 
Package: release.debian.org
Version: 11.7

Hi,

Each of the updates referred to in these requests was included in this
morning's 11.7 point release.

Regards,

Adam

--- End Message ---
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