From 83b086a16eb2bf36bf541bc100bc1083fcc2d579 Mon Sep 17 00:00:00 2001
From: Alexander Volkov <a.volkov@rusbitech.ru>
Date: Mon, 18 Feb 2019 15:28:22 +0300
Subject: [PATCH] shm: Always try to set F_SEAL_SHRINK for created SHM files

Sealing is working not only for files created by memfd_create(),
but also on tmpfs files.
---
 Xext/shm.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Xext/shm.c b/Xext/shm.c
index 506fd4df1..5c10ad4ef 100644
--- a/Xext/shm.c
+++ b/Xext/shm.c
@@ -1207,7 +1207,6 @@ shm_tmpfile(void)
 #ifdef HAVE_MEMFD_CREATE
     fd = memfd_create("xorg", MFD_CLOEXEC|MFD_ALLOW_SEALING);
     if (fd != -1) {
-        fcntl(fd, F_ADD_SEALS, F_SEAL_SHRINK);
         DebugF ("Using memfd_create\n");
         return fd;
     }
@@ -1274,6 +1273,9 @@ ProcShmCreateSegment(ClientPtr client)
         close(fd);
         return BadAlloc;
     }
+#if defined(F_ADD_SEALS) && defined(F_SEAL_SHRINK)
+    fcntl(fd, F_ADD_SEALS, F_SEAL_SHRINK);
+#endif
     shmdesc = malloc(sizeof(ShmDescRec));
     if (!shmdesc) {
         close(fd);