fs: move should_remove_suid()

commit e243e3f94c804ecca9a8241b5babe28f35258ef4 upstream.

Move the helper from inode.c to attr.c. This keeps the the core of the
set{g,u}id stripping logic in one place when we add follow-up changes.
It is the better place anyway, since should_remove_suid() returns
ATTR_KILL_S{G,U}ID flags.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Tested-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/attr.c b/fs/attr.c
index 686840aa91c8bfd32572c40707c69a05174ee47d..f045431bab1adc74a560d3c432602c2bcea341c5 100644 (file)
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -20,6 +20,35 @@
 
 #include "internal.h"
 
+/*
+ * The logic we want is
+ *
+ *     if suid or (sgid and xgrp)
+ *             remove privs
+ */
+int should_remove_suid(struct dentry *dentry)
+{
+       umode_t mode = d_inode(dentry)->i_mode;
+       int kill = 0;
+
+       /* suid always must be killed */
+       if (unlikely(mode & S_ISUID))
+               kill = ATTR_KILL_SUID;
+
+       /*
+        * sgid without any exec bits is just a mandatory locking mark; leave
+        * it alone.  If some exec bits are set, it's a real sgid; kill it.
+        */
+       if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
+               kill |= ATTR_KILL_SGID;
+
+       if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode)))
+               return kill;
+
+       return 0;
+}
+EXPORT_SYMBOL(should_remove_suid);
+
 /**
  * chown_ok - verify permissions to chown inode
  * @mnt_userns:        user namespace of the mount @inode was found from

diff --git a/fs/inode.c b/fs/inode.c
index a71fb82279bb1be3fab9a84d4cc6f805b84166d8..3811269259e116a08b8b9c7b663af5217aaeefbb 100644 (file)
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1864,35 +1864,6 @@ skip_update:
 }
 EXPORT_SYMBOL(touch_atime);
 
-/*
- * The logic we want is
- *
- *     if suid or (sgid and xgrp)
- *             remove privs
- */
-int should_remove_suid(struct dentry *dentry)
-{
-       umode_t mode = d_inode(dentry)->i_mode;
-       int kill = 0;
-
-       /* suid always must be killed */
-       if (unlikely(mode & S_ISUID))
-               kill = ATTR_KILL_SUID;
-
-       /*
-        * sgid without any exec bits is just a mandatory locking mark; leave
-        * it alone.  If some exec bits are set, it's a real sgid; kill it.
-        */
-       if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
-               kill |= ATTR_KILL_SGID;
-
-       if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode)))
-               return kill;
-
-       return 0;
-}
-EXPORT_SYMBOL(should_remove_suid);
-
 /*
  * Return mask of changes for notify_change() that need to be done as a
  * response to write or truncate. Return 0 if nothing has to be changed.