From e522de480891b9d72ba4cd2d4c8decb6909809a9 Mon Sep 17 00:00:00 2001
From: Herb Lewis <herb@samba.org>
Date: Wed, 10 May 2000 00:05:27 +0000
Subject: Using a structure for a tdb key can lead to insideous, hard to find
 bugs. On 64 bit IRIX, structure packing means that a struct { SMB_DEV_T dev
 /* 4 bytes */ SMB_INO_T ino /* 8 bytes */ }

has 4 bytes of padding between the two members. If you
don't null the memory before using it as a tdb key,
you randomly can't find keys depending on what is in
the padding. This caused me immense pain and was hard
to track down.... :-)

Jeremy.
(This used to be commit f2a5ba3f0939f59097f0ef6a25f1cf9b5574f157)
---
 source3/locking/brlock.c  | 41 +++++++++++++++++++++--------------------
 source3/locking/locking.c |  2 ++
 source3/locking/posix.c   |  2 ++
 3 files changed, 25 insertions(+), 20 deletions(-)

(limited to 'source3/locking')

diff --git a/source3/locking/brlock.c b/source3/locking/brlock.c
index 78a9174141..933fc142e9 100644
--- a/source3/locking/brlock.c
+++ b/source3/locking/brlock.c
@@ -63,6 +63,23 @@ struct lock_key {
 
 static TDB_CONTEXT *tdb;
 
+/****************************************************************************
+ Create a locking key - ensuring zero filled for pad purposes.
+****************************************************************************/
+
+static TDB_DATA locking_key(SMB_DEV_T dev, SMB_INO_T inode)
+{
+        static struct lock_key key;
+        TDB_DATA kbuf;
+
+        memset(&key, '\0', sizeof(key));
+        key.device = dev;
+        key.inode = inode;
+        kbuf.dptr = (char *)&key;
+        kbuf.dsize = sizeof(key);
+        return kbuf;
+}
+
 /****************************************************************************
  See if two locking contexts are equal.
 ****************************************************************************/
@@ -163,15 +180,11 @@ BOOL brl_lock(SMB_DEV_T dev, SMB_INO_T ino, int fnum,
 	      br_off start, br_off size, 
 	      enum brl_type lock_type)
 {
-	struct lock_key key;
 	TDB_DATA kbuf, dbuf;
 	int count, i;
 	struct lock_struct lock, *locks;
 
-	key.device = dev;
-	key.inode = ino;
-	kbuf.dptr = (char *)&key;
-	kbuf.dsize = sizeof(key);
+	kbuf = locking_key(dev,ino);
 
 	dbuf.dptr = NULL;
 
@@ -222,16 +235,12 @@ BOOL brl_unlock(SMB_DEV_T dev, SMB_INO_T ino, int fnum,
 		uint16 smbpid, pid_t pid, uint16 tid,
 		br_off start, br_off size)
 {
-	struct lock_key key;
 	TDB_DATA kbuf, dbuf;
 	int count, i;
 	struct lock_struct *locks;
 	struct lock_context context;
 
-	key.device = dev;
-	key.inode = ino;
-	kbuf.dptr = (char *)&key;
-	kbuf.dsize = sizeof(key);
+	kbuf = locking_key(dev,ino);
 
 	dbuf.dptr = NULL;
 
@@ -305,15 +314,11 @@ BOOL brl_locktest(SMB_DEV_T dev, SMB_INO_T ino, int fnum,
 		  br_off start, br_off size, 
 		  enum brl_type lock_type)
 {
-	struct lock_key key;
 	TDB_DATA kbuf, dbuf;
 	int count, i;
 	struct lock_struct lock, *locks;
 
-	key.device = dev;
-	key.inode = ino;
-	kbuf.dptr = (char *)&key;
-	kbuf.dsize = sizeof(key);
+	kbuf = locking_key(dev,ino);
 
 	dbuf.dptr = NULL;
 
@@ -356,15 +361,11 @@ BOOL brl_locktest(SMB_DEV_T dev, SMB_INO_T ino, int fnum,
 
 void brl_close(SMB_DEV_T dev, SMB_INO_T ino, pid_t pid, int tid, int fnum)
 {
-	struct lock_key key;
 	TDB_DATA kbuf, dbuf;
 	int count, i, dcount=0;
 	struct lock_struct *locks;
 
-	key.device = dev;
-	key.inode = ino;
-	kbuf.dptr = (char *)&key;
-	kbuf.dsize = sizeof(key);
+	kbuf = locking_key(dev,ino);
 
 	dbuf.dptr = NULL;
 
diff --git a/source3/locking/locking.c b/source3/locking/locking.c
index 07411e8919..302b5b56c9 100644
--- a/source3/locking/locking.c
+++ b/source3/locking/locking.c
@@ -255,6 +255,8 @@ static TDB_DATA locking_key(SMB_DEV_T dev, SMB_INO_T inode)
 {
 	static struct locking_key key;
 	TDB_DATA kbuf;
+
+	memset(&key, '\0', sizeof(key));
 	key.dev = dev;
 	key.inode = inode;
 	kbuf.dptr = (char *)&key;
diff --git a/source3/locking/posix.c b/source3/locking/posix.c
index 0ab46f9ca4..d1edb1ef57 100644
--- a/source3/locking/posix.c
+++ b/source3/locking/posix.c
@@ -73,6 +73,8 @@ static TDB_DATA locking_key(SMB_DEV_T dev, SMB_INO_T inode)
 {
 	static struct posix_lock_key key;
 	TDB_DATA kbuf;
+
+	memset(&key, '\0', sizeof(key));
 	key.device = dev;
 	key.inode = inode;
 	kbuf.dptr = (char *)&key;
-- 
cgit