[kernel] zero struct memory in ipc shm (CVE-2010-4072)

[Kyle McMartin]

commit 205e1d9754dc714ba93939501079ea6bedde3371
Author: Kyle McMartin <kyle at mcmartin.ca>
Date:   Tue Nov 23 10:55:43 2010 -0500

    zero struct memory in ipc shm (CVE-2010-4072)

 ipc-shm-fix-information-leak-to-user.patch |   30 ++++++++++++++++++++++++++++
 kernel.spec                                |    5 ++++
 2 files changed, 35 insertions(+), 0 deletions(-)
---
diff --git a/ipc-shm-fix-information-leak-to-user.patch b/ipc-shm-fix-information-leak-to-user.patch
new file mode 100644
index 0000000..b23ad43
--- /dev/null
+++ b/ipc-shm-fix-information-leak-to-user.patch
@@ -0,0 +1,30 @@
+From: Vasiliy Kulikov <segooon at gmail.com>
+Date: Sat, 30 Oct 2010 14:22:49 +0000 (+0400)
+Subject: ipc: shm: fix information leak to userland
+X-Git-Tag: v2.6.37-rc1~24
+X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=3af54c9bd9e6f14f896aac1bb0e8405ae0bc7a44
+
+ipc: shm: fix information leak to userland
+
+The shmid_ds structure is copied to userland with shm_unused{,2,3}
+fields unitialized.  It leads to leaking of contents of kernel stack
+memory.
+
+Signed-off-by: Vasiliy Kulikov <segooon at gmail.com>
+Acked-by: Al Viro <viro at ZenIV.linux.org.uk>
+Cc: stable at kernel.org
+Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
+---
+
+diff --git a/ipc/shm.c b/ipc/shm.c
+index fd658a1..7d3bb22 100644
+--- a/ipc/shm.c
++++ b/ipc/shm.c
+@@ -479,6 +479,7 @@ static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_
+ 	    {
+ 		struct shmid_ds out;
+ 
++		memset(&out, 0, sizeof(out));
+ 		ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
+ 		out.shm_segsz	= in->shm_segsz;
+ 		out.shm_atime	= in->shm_atime;
diff --git a/kernel.spec b/kernel.spec
index d3188d4..2684a58 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -731,6 +731,7 @@ Patch12307: tty-restore-tty_ldisc_wait_idle.patch
 Patch12308: fix-i8k-inline-asm.patch
 
 Patch12400: ipc-zero-struct-memory-for-compat-fns.patch
+Patch12401: ipc-shm-fix-information-leak-to-user.patch
 
 %endif
 
@@ -1359,6 +1360,9 @@ ApplyPatch fix-i8k-inline-asm.patch
 # rhbz#648658 (CVE-2010-4073)
 ApplyPatch ipc-zero-struct-memory-for-compat-fns.patch
 
+# rhbz#648656 (CVE-2010-4072)
+ApplyPatch ipc-shm-fix-information-leak-to-user.patch
+
 # END OF PATCH APPLICATIONS
 
 %endif
@@ -1974,6 +1978,7 @@ fi
 %changelog
 * Tue Nov 23 2010 Kyle McMartin <kyle at redhat.com>
 - zero struct memory in ipc compat (CVE-2010-4073) (#648658)
+- zero struct memory in ipc shm (CVE-2010-4072) (#648656)
 
 * Tue Nov 23 2010 Kyle McMartin <kyle at redhat.com>
 - fix-i8k-inline-asm.patch: backport gcc miscompilation fix from git