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

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 <[email protected]> know about it.

From: Eric Biggers <[email protected]>
Date: Thu, 13 Jul 2017 13:16:56 +0100
Subject: KEYS: DH: validate __spare field

From: Eric Biggers <[email protected]>

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.

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

@@ -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);
 }

@@ -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 [email protected] are

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