[PATCH 1/2] ipc: initialize structure memory to zero for compat functions CVE-2010-4073

[Paolo Pisati]

From: Dan Rosenberg <drosenberg at vsecurity.com>

BugLink: http://bugs.laaunchpad.net/bugs/806366

commit upstream 6faca004a930b8aafd9c4bd58673ca7420aa2006

This takes care of leaking uninitialized kernel stack memory to
userspace from non-zeroed fields in structs in compat ipc functions.

CVE-2010-4073

Signed-off-by: Dan Rosenberg <drosenberg at vsecurity.com>
Cc: Manfred Spraul <manfred at colorfullife.com>
Cc: Arnd Bergmann <arnd at arndb.de>
Cc: <stable at kernel.org>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
Signed-off-by: Steve Conklin <sconklin at canonical.com>
Signed-off-by: Paolo Pisati <paolo.pisati at canonical.com>
---
 ipc/compat.c    |    6 ++++++
 ipc/compat_mq.c |    5 +++++
 2 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/ipc/compat.c b/ipc/compat.c
index ab76fb0..5e3e3a1 100644
--- a/ipc/compat.c
+++ b/ipc/compat.c
@@ -242,6 +242,8 @@ long compat_sys_semctl(int first, int second, int third, void __user *uptr)
 	struct semid64_ds __user *up64;
 	int version = compat_ipc_parse_version(&third);
 
+	memset(&s64, 0, sizeof(s64));
+
 	if (!uptr)
 		return -EINVAL;
 	if (get_user(pad, (u32 __user *) uptr))
@@ -422,6 +424,8 @@ long compat_sys_msgctl(int first, int second, void __user *uptr)
 	int version = compat_ipc_parse_version(&second);
 	void __user *p;
 
+	memset(&m64, 0, sizeof(m64));
+
 	switch (second & (~IPC_64)) {
 	case IPC_INFO:
 	case IPC_RMID:
@@ -595,6 +599,8 @@ long compat_sys_shmctl(int first, int second, void __user *uptr)
 	int err, err2;
 	int version = compat_ipc_parse_version(&second);
 
+	memset(&s64, 0, sizeof(s64));
+
 	switch (second & (~IPC_64)) {
 	case IPC_RMID:
 	case SHM_LOCK:
diff --git a/ipc/compat_mq.c b/ipc/compat_mq.c
index d8d1e9f..380ea4f 100644
--- a/ipc/compat_mq.c
+++ b/ipc/compat_mq.c
@@ -53,6 +53,9 @@ asmlinkage long compat_sys_mq_open(const char __user *u_name,
 	void __user *p = NULL;
 	if (u_attr && oflag & O_CREAT) {
 		struct mq_attr attr;
+
+		memset(&attr, 0, sizeof(attr));
+
 		p = compat_alloc_user_space(sizeof(attr));
 		if (get_compat_mq_attr(&attr, u_attr) ||
 		    copy_to_user(p, &attr, sizeof(attr)))
@@ -127,6 +130,8 @@ asmlinkage long compat_sys_mq_getsetattr(mqd_t mqdes,
 	struct mq_attr __user *p = compat_alloc_user_space(2 * sizeof(*p));
 	long ret;
 
+	memset(&mqstat, 0, sizeof(mqstat));
+
 	if (u_mqstat) {
 		if (get_compat_mq_attr(&mqstat, u_mqstat) ||
 		    copy_to_user(p, &mqstat, sizeof(mqstat)))
-- 
1.7.5.3