screen: backport fix for CVE-2023-24626

(From OE-Core rev: 26242b20d407d5e498083d7e6fa082153be75092)

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 41 insertions, 0 deletions

diff --git a/meta/recipes-extended/screen/screen/signal-permission.patch b/meta/recipes-extended/screen/screen/signal-permission.patch
new file mode 100644
index 0000000000..77dc649090
--- /dev/null
+++ b/meta/recipes-extended/screen/screen/signal-permission.patch
@@ -0,0 +1,40 @@
+From e9ad41bfedb4537a6f0de20f00b27c7739f168f7 Mon Sep 17 00:00:00 2001
+From: Alexander Naumov <alexander_naumov@opensuse.org>
+Date: Mon, 30 Jan 2023 17:22:25 +0200
+Subject: fix: missing signal sending permission check on failed query messages
+
+Signed-off-by: Alexander Naumov <alexander_naumov@opensuse.org>
+
+CVE: CVE-2023-24626
+Upstream-Status: Backport
+Signed-off-by: Ross Burton <ross.burton@arm.com>
+---
+ src/socket.c | 9 +++++++--
+ 1 file changed, 7 insertions(+), 2 deletions(-)
+
+diff --git a/src/socket.c b/src/socket.c
+index 147dc54..54d8cb8 100644
+--- a/socket.c
++++ b/socket.c
+@@ -1285,11 +1285,16 @@ ReceiveMsg()
+           else
+             queryflag = -1;
+ 
+-          Kill(m.m.command.apid,
++          if (CheckPid(m.m.command.apid)) {
++            Msg(0, "Query attempt with bad pid(%d)!", m.m.command.apid);
++          }
++          else {
++            Kill(m.m.command.apid,
+                (queryflag >= 0)
+                    ? SIGCONT
+                    : SIG_BYE); /* Send SIG_BYE if an error happened */
+-          queryflag = -1;
++            queryflag = -1;
++          }
+         }
+         break;
+       case MSG_COMMAND:
+-- 
+cgit v1.1
+
diff --git a/meta/recipes-extended/screen/screen_4.9.0.bb b/meta/recipes-extended/screen/screen_4.9.0.bb
index 77e8000bf3..235cd8c6cf 100644
--- a/meta/recipes-extended/screen/screen_4.9.0.bb
+++ b/meta/recipes-extended/screen/screen_4.9.0.bb
@@ -22,6 +22,7 @@ SRC_URI = "${GNU_MIRROR}/screen/screen-${PV}.tar.gz \
            file://0001-fix-for-multijob-build.patch \
            file://0001-Remove-more-compatibility-stuff.patch \
            file://0001-configure-Add-needed-system-headers-in-checks.patch \
+           file://signal-permission.patch \
            "
 
 SRC_URI[sha256sum] = "f9335281bb4d1538ed078df78a20c2f39d3af9a4e91c57d084271e0289c730f4"