[Buildroot] [git commit branch/2024.02.x] package/skeleton-init-sysv: Set sticky bit on /dev/shm

[Peter Korsgaard]

commit: https://git.buildroot.net/buildroot/commit/?id=3d1c04c05c27c206e336ad7338d0a882c9c4736d
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2024.02.x

/dev/shm is a world-writable directory, like /tmp, and should also
have the sticky bit set.  Without this, any user can delete and
replace another user's files in /dev/shm.

This bug has been present since /dev/shm was added to the skeleton
/etc/fstab, but appears to have been fixed for systems using systemd
by commit 76fc9275f14e "system: separate sysv and systemd parts of the
skeleton" which went into Buildroot 2017.08.

Signed-off-by: Ben Hutchings <ben.hutchings at mind.be>
Fixes: 22fde22e35f98f7830c2f8955465532328348cd1
Signed-off-by: Yann E. MORIN <yann.morin.1998 at free.fr>
(cherry picked from commit 0b2967e15800421efbdfe3a7a6061cf6bd84134d)
Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
---
 package/skeleton-init-sysv/skeleton/etc/fstab | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package/skeleton-init-sysv/skeleton/etc/fstab b/package/skeleton-init-sysv/skeleton/etc/fstab
index 169054b74f..06c20fe9d5 100644
--- a/package/skeleton-init-sysv/skeleton/etc/fstab
+++ b/package/skeleton-init-sysv/skeleton/etc/fstab
@@ -2,7 +2,7 @@
 /dev/root	/		ext2	rw,noauto	0	1
 proc		/proc		proc	defaults	0	0
 devpts		/dev/pts	devpts	defaults,gid=5,mode=620,ptmxmode=0666	0	0
-tmpfs		/dev/shm	tmpfs	mode=0777	0	0
+tmpfs		/dev/shm	tmpfs	mode=1777	0	0
 tmpfs		/tmp		tmpfs	mode=1777	0	0
 tmpfs		/run		tmpfs	mode=0755,nosuid,nodev	0	0
 sysfs		/sys		sysfs	defaults	0	0