lxc: backport patch to fix CVE-2022-47952langdale

Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

2 files changed, 77 insertions, 0 deletions

diff --git a/recipes-containers/lxc/files/0001-Patching-an-incoming-CVE-CVE-2022-47952.patch b/recipes-containers/lxc/files/0001-Patching-an-incoming-CVE-CVE-2022-47952.patch
new file mode 100644
index 00000000..d5a02f40
--- /dev/null
+++ b/recipes-containers/lxc/files/0001-Patching-an-incoming-CVE-CVE-2022-47952.patch
@@ -0,0 +1,76 @@
+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!
+
+Upstream-Status: Backport from https://github.com/lxc/lxc/commit/1b0469530d7a38b8f8990e114b52530d1bf7f3b8
+CVE: CVE-2022-47952
+
+Signed-off-by: MaherAzzouzi <maherazz04@gmail.com>
+Acked-by: Serge Hallyn <serge@hallyn.com>
+Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.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 a91e2259d..69bc6f17d 100644
+--- a/src/lxc/cmd/lxc_user_nic.c
++++ b/src/lxc/cmd/lxc_user_nic.c
+@@ -1085,20 +1085,17 @@ 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);
+                }
+@@ -1112,7 +1109,7 @@ 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);
+                }
+-- 
+2.34.1
+
diff --git a/recipes-containers/lxc/lxc_git.bb b/recipes-containers/lxc/lxc_git.bb
index 9cabe054..a99d7ee7 100644
--- a/recipes-containers/lxc/lxc_git.bb
+++ b/recipes-containers/lxc/lxc_git.bb
@@ -47,6 +47,7 @@ SRC_URI = "git://github.com/lxc/lxc.git;branch=master;protocol=https \
         file://0001-use-sd_bus_call_method_async-to-replace-the-asyncv-o.patch \
         file://dnsmasq.conf \
         file://lxc-net \
+        file://0001-Patching-an-incoming-CVE-CVE-2022-47952.patch \
         "
 
 SRCREV = "133aa416ca2a5996090ec0e697e253646364d274"