[kernel] initialize struct memory to zero in ipc compat (CVE-2010-4073)

[Kyle McMartin]

commit 79bb6459c7ef296ddc40393eb4da4bcffd3329d9
Author: Kyle McMartin <kyle at mcmartin.ca>
Date:   Tue Nov 23 10:06:02 2010 -0500

    initialize struct memory to zero in ipc compat (CVE-2010-4073)

 ipc-zero-struct-memory-for-compat-fns.patch |   73 +++++++++++++++++++++++++++
 kernel.spec                                 |    8 +++
 2 files changed, 81 insertions(+), 0 deletions(-)
---
diff --git a/ipc-zero-struct-memory-for-compat-fns.patch b/ipc-zero-struct-memory-for-compat-fns.patch
new file mode 100644
index 0000000..b682c7d
--- /dev/null
+++ b/ipc-zero-struct-memory-for-compat-fns.patch
@@ -0,0 +1,73 @@
+From: Dan Rosenberg <drosenberg at vsecurity.com>
+Date: Wed, 27 Oct 2010 22:34:17 +0000 (-0700)
+Subject: ipc: initialize structure memory to zero for compat functions
+X-Git-Tag: v2.6.37-rc1~85^2~50
+X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=03145beb455cf5c20a761e8451e30b8a74ba58d9
+
+ipc: initialize structure memory to zero for compat functions
+
+This takes care of leaking uninitialized kernel stack memory to
+userspace from non-zeroed fields in structs in compat ipc functions.
+
+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>
+---
+
+diff --git a/ipc/compat.c b/ipc/compat.c
+index 9dc2c7d..845a287 100644
+--- a/ipc/compat.c
++++ b/ipc/compat.c
+@@ -241,6 +241,8 @@ 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))
+@@ -421,6 +423,8 @@ 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:
+@@ -594,6 +598,8 @@ 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)))
diff --git a/kernel.spec b/kernel.spec
index 8b08076..d3188d4 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -730,6 +730,8 @@ Patch12307: tty-restore-tty_ldisc_wait_idle.patch
 
 Patch12308: fix-i8k-inline-asm.patch
 
+Patch12400: ipc-zero-struct-memory-for-compat-fns.patch
+
 %endif
 
 BuildRoot: %{_tmppath}/kernel-%{KVERREL}-root
@@ -1354,6 +1356,9 @@ ApplyPatch tty-restore-tty_ldisc_wait_idle.patch
 
 ApplyPatch fix-i8k-inline-asm.patch
 
+# rhbz#648658 (CVE-2010-4073)
+ApplyPatch ipc-zero-struct-memory-for-compat-fns.patch
+
 # END OF PATCH APPLICATIONS
 
 %endif
@@ -1968,6 +1973,9 @@ fi
 
 %changelog
 * Tue Nov 23 2010 Kyle McMartin <kyle at redhat.com>
+- zero struct memory in ipc compat (CVE-2010-4073) (#648658)
+
+* Tue Nov 23 2010 Kyle McMartin <kyle at redhat.com>
 - fix-i8k-inline-asm.patch: backport gcc miscompilation fix from git
   [22d3243d, 6b4e81db] (rhbz#647677)