Patch "KEYS: DH: validate __spare field" has been added to the 4.12-stable tree

Patch "KEYS: DH: validate __spare field" has been added to the 4.12-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    KEYS: DH: validate __spare field

to the 4.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     keys-dh-validate-__spare-field.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 4f9dabfaf8df971f8a3b6aa324f8f817be38d538 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@google.com>
Date: Thu, 13 Jul 2017 13:16:56 +0100
Subject: KEYS: DH: validate __spare field

From: Eric Biggers <ebiggers@google.com>

commit 4f9dabfaf8df971f8a3b6aa324f8f817be38d538 upstream.

Syscalls must validate that their reserved arguments are zero and return
EINVAL otherwise.  Otherwise, it will be impossible to actually use them
for anything in the future because existing programs may be passing
garbage in.  This is standard practice when adding new APIs.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 security/keys/compat_dh.c |    2 ++
 security/keys/dh.c        |    5 +++++
 2 files changed, 7 insertions(+)

--- a/security/keys/compat_dh.c
+++ b/security/keys/compat_dh.c
@@ -33,6 +33,8 @@ long compat_keyctl_dh_compute(struct key
 	kdfcopy.hashname = compat_ptr(compat_kdfcopy.hashname);
 	kdfcopy.otherinfo = compat_ptr(compat_kdfcopy.otherinfo);
 	kdfcopy.otherinfolen = compat_kdfcopy.otherinfolen;
+	memcpy(kdfcopy.__spare, compat_kdfcopy.__spare,
+	       sizeof(kdfcopy.__spare));
 
 	return __keyctl_dh_compute(params, buffer, buflen, &kdfcopy);
 }
--- a/security/keys/dh.c
+++ b/security/keys/dh.c
@@ -266,6 +266,11 @@ long __keyctl_dh_compute(struct keyctl_d
 	if (kdfcopy) {
 		char *hashname;
 
+		if (memchr_inv(kdfcopy->__spare, 0, sizeof(kdfcopy->__spare))) {
+			ret = -EINVAL;
+			goto out1;
+		}
+
 		if (buflen > KEYCTL_KDF_MAX_OUTPUT_LEN ||
 		    kdfcopy->otherinfolen > KEYCTL_KDF_MAX_OI_LEN) {
 			ret = -EMSGSIZE;


Patches currently in stable-queue which might be from ebiggers@google.com are

queue-4.12/parisc-use-compat_sys_keyctl.patch
queue-4.12/keys-dh-validate-__spare-field.patch