[PATCH] uml: make daemon transport behave properly

Avoid uninitialized data in the daemon_data structure.  I used this transport
before doing proper setup before-hand, and I got some very nice SLAB
corruption due to freeing crap pointers.  So just make sure to clear
everything when appropriate.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 10 insertions, 0 deletions

diff --git a/arch/um/drivers/daemon_kern.c b/arch/um/drivers/daemon_kern.c
index 30d285b266af..507e3cbac9d3 100644
--- a/arch/um/drivers/daemon_kern.c
+++ b/arch/um/drivers/daemon_kern.c
@@ -31,6 +31,10 @@ void daemon_init(struct net_device *dev, void *data)
         dpri->fd = -1;
         dpri->control = -1;
         dpri->dev = dev;
+        /* We will free this pointer. If it contains crap we're burned. */
+        dpri->ctl_addr = NULL;
+        dpri->data_addr = NULL;
+        dpri->local_addr = NULL;
 
         printk("daemon backend (uml_switch version %d) - %s:%s", 
                SWITCH_VERSION, dpri->sock_type, dpri->ctl_sock);
diff --git a/arch/um/drivers/daemon_user.c b/arch/um/drivers/daemon_user.c
index 1bb085b2824d..c944265955e2 100644
--- a/arch/um/drivers/daemon_user.c
+++ b/arch/um/drivers/daemon_user.c
@@ -158,10 +158,16 @@ static void daemon_remove(void *data)
         struct daemon_data *pri = data;
 
         os_close_file(pri->fd);
+        pri->fd = -1;
         os_close_file(pri->control);
+        pri->control = -1;
+
         kfree(pri->data_addr);
+        pri->data_addr = NULL;
         kfree(pri->ctl_addr);
+        pri->ctl_addr = NULL;
         kfree(pri->local_addr);
+        pri->local_addr = NULL;
 }
 
 int daemon_user_write(int fd, void *buf, int len, struct daemon_data *pri)