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authorAl Viro <viro@zeniv.linux.org.uk>2016-10-08 11:06:08 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2016-10-08 11:06:08 -0400
commite55f1d1d13e7f1c364672d667d78fd1f640ab9f9 (patch)
tree406a3c127abb008f2f736c8d2ee03fc3c2926d6b /fs/posix_acl.c
parentf334bcd94b7d3c0fbc34d518a86548f451ab5faf (diff)
parent030b533c4fd4d2ec3402363323de4bb2983c9cee (diff)
Merge remote-tracking branch 'jk/vfs' into work.misc
Diffstat (limited to 'fs/posix_acl.c')
-rw-r--r--fs/posix_acl.c31
1 files changed, 31 insertions, 0 deletions
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 87193924eb91..da3f760a7e88 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -627,6 +627,37 @@ err_release:
}
EXPORT_SYMBOL_GPL(posix_acl_create);
+/**
+ * posix_acl_update_mode - update mode in set_acl
+ *
+ * Update the file mode when setting an ACL: compute the new file permission
+ * bits based on the ACL. In addition, if the ACL is equivalent to the new
+ * file mode, set *acl to NULL to indicate that no ACL should be set.
+ *
+ * As with chmod, clear the setgit bit if the caller is not in the owning group
+ * or capable of CAP_FSETID (see inode_change_ok).
+ *
+ * Called from set_acl inode operations.
+ */
+int posix_acl_update_mode(struct inode *inode, umode_t *mode_p,
+ struct posix_acl **acl)
+{
+ umode_t mode = inode->i_mode;
+ int error;
+
+ error = posix_acl_equiv_mode(*acl, &mode);
+ if (error < 0)
+ return error;
+ if (error == 0)
+ *acl = NULL;
+ if (!in_group_p(inode->i_gid) &&
+ !capable_wrt_inode_uidgid(inode, CAP_FSETID))
+ mode &= ~S_ISGID;
+ *mode_p = mode;
+ return 0;
+}
+EXPORT_SYMBOL(posix_acl_update_mode);
+
/*
* Fix up the uids and gids in posix acl extended attributes in place.
*/