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* [PATCH 1/4] fs/posix_acl: apply umask if superblock disables ACL support
@ 2019-07-03 12:47 Max Kellermann
  2019-07-03 12:47 ` [PATCH 2/4] fs/ext4/acl: apply umask if ACL support is disabled Max Kellermann
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Max Kellermann @ 2019-07-03 12:47 UTC (permalink / raw)
  To: linux-fsdevel, linux-nfs, trond.myklebust, bfields, gregkh,
	tytso, adilger.kernel, hughd, anna.schumaker
  Cc: linux-kernel, Max Kellermann

The function posix_acl_create() applies the umask only if the inode
has no ACL (= NULL) or if ACLs are not supported by the filesystem
driver (= -EOPNOTSUPP).

However, this happens only after after the IS_POSIXACL() check
succeeeded.  If the superblock doesn't enable ACL support, umask will
never be applied.  A filesystem which has no ACL support will of
course not enable SB_POSIXACL, rendering the umask-applying code path
unreachable.

This fixes a bug which causes the umask to be ignored with O_TMPFILE
on tmpfs:

 https://github.com/MusicPlayerDaemon/MPD/issues/558
 https://bugs.gentoo.org/show_bug.cgi?id=686142#c3
 https://bugzilla.kernel.org/show_bug.cgi?id=203625

Signed-off-by: Max Kellermann <max.kellermann@gmail.com>
---
 fs/posix_acl.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 2fd0fde16fe1..815f7b36ef94 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -588,9 +588,14 @@ posix_acl_create(struct inode *dir, umode_t *mode,
 	*acl = NULL;
 	*default_acl = NULL;
 
-	if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
+	if (S_ISLNK(*mode))
 		return 0;
 
+	if (!IS_POSIXACL(dir)) {
+		*mode &= ~current_umask();
+		return 0;
+	}
+
 	p = get_acl(dir, ACL_TYPE_DEFAULT);
 	if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
 		*mode &= ~current_umask();
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2019-07-03 12:48 UTC | newest]

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-- links below jump to the message on this page --
2019-07-03 12:47 [PATCH 1/4] fs/posix_acl: apply umask if superblock disables ACL support Max Kellermann
2019-07-03 12:47 ` [PATCH 2/4] fs/ext4/acl: apply umask if ACL support is disabled Max Kellermann
2019-07-03 12:47 ` [PATCH 3/4] linux/fs.h: fix umask on NFS with CONFIG_FS_POSIX_ACL=n Max Kellermann
2019-07-03 12:47 ` [PATCH 4/4] nfs/super: check NFS_CAP_ACLS instead of the NFS version Max Kellermann

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