This is a note to let you know that I've just added the patch titled
KEYS: reject NULL restriction string when type is specified
to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: keys-reject-null-restriction-string-when-type-is-specified.patch and it can be found in the queue-4.14 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 18026d866801d0c52e5550210563222bd6c7191d Mon Sep 17 00:00:00 2001
From: Eric Biggers ebiggers@google.com Date: Fri, 8 Dec 2017 15:13:29 +0000 Subject: KEYS: reject NULL restriction string when type is specified
From: Eric Biggers ebiggers@google.com
commit 18026d866801d0c52e5550210563222bd6c7191d upstream.
keyctl_restrict_keyring() allows through a NULL restriction when the "type" is non-NULL, which causes a NULL pointer dereference in asymmetric_lookup_restriction() when it calls strcmp() on the restriction string.
But no key types actually use a "NULL restriction" to mean anything, so update keyctl_restrict_keyring() to reject it with EINVAL.
Reported-by: syzbot syzkaller@googlegroups.com Fixes: 97d3aa0f3134 ("KEYS: Add a lookup_restriction function for the asymmetric key type") Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: David Howells dhowells@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- security/keys/keyctl.c | 24 ++++++++++-------------- 1 file changed, 10 insertions(+), 14 deletions(-)
--- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -1588,9 +1588,8 @@ error_keyring: * The caller must have Setattr permission to change keyring restrictions. * * The requested type name may be a NULL pointer to reject all attempts - * to link to the keyring. If _type is non-NULL, _restriction can be - * NULL or a pointer to a string describing the restriction. If _type is - * NULL, _restriction must also be NULL. + * to link to the keyring. In this case, _restriction must also be NULL. + * Otherwise, both _type and _restriction must be non-NULL. * * Returns 0 if successful. */ @@ -1598,7 +1597,6 @@ long keyctl_restrict_keyring(key_serial_ const char __user *_restriction) { key_ref_t key_ref; - bool link_reject = !_type; char type[32]; char *restriction = NULL; long ret; @@ -1607,31 +1605,29 @@ long keyctl_restrict_keyring(key_serial_ if (IS_ERR(key_ref)) return PTR_ERR(key_ref);
+ ret = -EINVAL; if (_type) { + if (!_restriction) + goto error; + ret = key_get_type_from_user(type, _type, sizeof(type)); if (ret < 0) goto error; - } - - if (_restriction) { - if (!_type) { - ret = -EINVAL; - goto error; - }
restriction = strndup_user(_restriction, PAGE_SIZE); if (IS_ERR(restriction)) { ret = PTR_ERR(restriction); goto error; } + } else { + if (_restriction) + goto error; }
- ret = keyring_restrict(key_ref, link_reject ? NULL : type, restriction); + ret = keyring_restrict(key_ref, _type ? type : NULL, restriction); kfree(restriction); - error: key_ref_put(key_ref); - return ret; }
Patches currently in stable-queue which might be from ebiggers@google.com are
queue-4.14/x.509-reject-invalid-bit-string-for-subjectpublickey.patch queue-4.14/asn.1-check-for-error-from-asn1_op_end__act-actions.patch queue-4.14/keys-add-missing-permission-check-for-request_key-destination.patch queue-4.14/asn.1-fix-out-of-bounds-read-when-parsing-indefinite-length-item.patch queue-4.14/keys-reject-null-restriction-string-when-type-is-specified.patch queue-4.14/x.509-fix-comparisons-of-pkey_algo.patch