Merge branch 'fix-max-write' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm

torvalds · torvalds · commit fe547d771478 · 2013-02-05T20:50:11.000+11:00
Pull dlm fix from David Teigland:
 "Thanks to Jana who reported the problem and was able to test this fix
  so quickly."

This fixes an incorrect size check that triggered for CONFIG_COMPAT
whether the code was actually doing compat or not.  The incorrect write
size check broke userland (clvmd) when maximum resource name lengths are
used.

* 'fix-max-write' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm:
  dlm: check the write size from user
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
@@ -503,11 +503,11 @@ static ssize_t device_write(struct file *file, const char __user *buf,
 #endif
 		return -EINVAL;
 
-#ifdef CONFIG_COMPAT
-	if (count > sizeof(struct dlm_write_request32) + DLM_RESNAME_MAXLEN)
-#else
+	/*
+	 * can't compare against COMPAT/dlm_write_request32 because
+	 * we don't yet know if is64bit is zero
+	 */
 	if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
-#endif
 		return -EINVAL;
 
 	kbuf = kzalloc(count + 1, GFP_NOFS);
