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authorJames Morris <james.l.morris@oracle.com>2017-09-28 02:11:28 +0300
committerJames Morris <james.l.morris@oracle.com>2017-09-28 02:11:28 +0300
commit2569e7e1d684e418ba7ffc9d0ad9a5f5247df0a0 (patch)
tree61ed98d4a5c453dca511c548213d364ce75711d0 /security
parent9cd6681cb1169e815c41af0265165dd1b872f228 (diff)
parent428490e38b2e352812e0b765d8bceafab0ec441d (diff)
downloadlinux-2569e7e1d684e418ba7ffc9d0ad9a5f5247df0a0.tar.xz
Merge commit 'keys-fixes-20170927' into fixes-v4.14-rc3
From David Howells: "There are two sets of patches here: (1) A bunch of core keyrings bug fixes from Eric Biggers. (2) Fixing big_key to use safe crypto from Jason A. Donenfeld."
Diffstat (limited to 'security')
-rw-r--r--security/keys/Kconfig4
-rw-r--r--security/keys/big_key.c139
-rw-r--r--security/keys/internal.h2
-rw-r--r--security/keys/key.c6
-rw-r--r--security/keys/keyctl.c13
-rw-r--r--security/keys/keyring.c37
-rw-r--r--security/keys/proc.c8
-rw-r--r--security/keys/process_keys.c6
-rw-r--r--security/keys/request_key_auth.c74
9 files changed, 137 insertions, 152 deletions
diff --git a/security/keys/Kconfig b/security/keys/Kconfig
index a7a23b5541f8..91eafada3164 100644
--- a/security/keys/Kconfig
+++ b/security/keys/Kconfig
@@ -45,10 +45,8 @@ config BIG_KEYS
bool "Large payload keys"
depends on KEYS
depends on TMPFS
- depends on (CRYPTO_ANSI_CPRNG = y || CRYPTO_DRBG = y)
select CRYPTO_AES
- select CRYPTO_ECB
- select CRYPTO_RNG
+ select CRYPTO_GCM
help
This option provides support for holding large keys within the kernel
(for example Kerberos ticket caches). The data may be stored out to
diff --git a/security/keys/big_key.c b/security/keys/big_key.c
index 6acb00f6f22c..e607830b6154 100644
--- a/security/keys/big_key.c
+++ b/security/keys/big_key.c
@@ -1,5 +1,6 @@
/* Large capacity key type
*
+ * Copyright (C) 2017 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
* Copyright (C) 2013 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
@@ -16,10 +17,10 @@
#include <linux/shmem_fs.h>
#include <linux/err.h>
#include <linux/scatterlist.h>
+#include <linux/random.h>
#include <keys/user-type.h>
#include <keys/big_key-type.h>
-#include <crypto/rng.h>
-#include <crypto/skcipher.h>
+#include <crypto/aead.h>
/*
* Layout of key payload words.
@@ -49,7 +50,12 @@ enum big_key_op {
/*
* Key size for big_key data encryption
*/
-#define ENC_KEY_SIZE 16
+#define ENC_KEY_SIZE 32
+
+/*
+ * Authentication tag length
+ */
+#define ENC_AUTHTAG_SIZE 16
/*
* big_key defined keys take an arbitrary string as the description and an
@@ -64,57 +70,62 @@ struct key_type key_type_big_key = {
.destroy = big_key_destroy,
.describe = big_key_describe,
.read = big_key_read,
+ /* no ->update(); don't add it without changing big_key_crypt() nonce */
};
/*
- * Crypto names for big_key data encryption
+ * Crypto names for big_key data authenticated encryption
*/
-static const char big_key_rng_name[] = "stdrng";
-static const char big_key_alg_name[] = "ecb(aes)";
+static const char big_key_alg_name[] = "gcm(aes)";
/*
- * Crypto algorithms for big_key data encryption
+ * Crypto algorithms for big_key data authenticated encryption
*/
-static struct crypto_rng *big_key_rng;
-static struct crypto_skcipher *big_key_skcipher;
+static struct crypto_aead *big_key_aead;
/*
- * Generate random key to encrypt big_key data
+ * Since changing the key affects the entire object, we need a mutex.
*/
-static inline int big_key_gen_enckey(u8 *key)
-{
- return crypto_rng_get_bytes(big_key_rng, key, ENC_KEY_SIZE);
-}
+static DEFINE_MUTEX(big_key_aead_lock);
/*
* Encrypt/decrypt big_key data
*/
static int big_key_crypt(enum big_key_op op, u8 *data, size_t datalen, u8 *key)
{
- int ret = -EINVAL;
+ int ret;
struct scatterlist sgio;
- SKCIPHER_REQUEST_ON_STACK(req, big_key_skcipher);
-
- if (crypto_skcipher_setkey(big_key_skcipher, key, ENC_KEY_SIZE)) {
+ struct aead_request *aead_req;
+ /* We always use a zero nonce. The reason we can get away with this is
+ * because we're using a different randomly generated key for every
+ * different encryption. Notably, too, key_type_big_key doesn't define
+ * an .update function, so there's no chance we'll wind up reusing the
+ * key to encrypt updated data. Simply put: one key, one encryption.
+ */
+ u8 zero_nonce[crypto_aead_ivsize(big_key_aead)];
+
+ aead_req = aead_request_alloc(big_key_aead, GFP_KERNEL);
+ if (!aead_req)
+ return -ENOMEM;
+
+ memset(zero_nonce, 0, sizeof(zero_nonce));
+ sg_init_one(&sgio, data, datalen + (op == BIG_KEY_ENC ? ENC_AUTHTAG_SIZE : 0));
+ aead_request_set_crypt(aead_req, &sgio, &sgio, datalen, zero_nonce);
+ aead_request_set_callback(aead_req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
+ aead_request_set_ad(aead_req, 0);
+
+ mutex_lock(&big_key_aead_lock);
+ if (crypto_aead_setkey(big_key_aead, key, ENC_KEY_SIZE)) {
ret = -EAGAIN;
goto error;
}
-
- skcipher_request_set_tfm(req, big_key_skcipher);
- skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
- NULL, NULL);
-
- sg_init_one(&sgio, data, datalen);
- skcipher_request_set_crypt(req, &sgio, &sgio, datalen, NULL);
-
if (op == BIG_KEY_ENC)
- ret = crypto_skcipher_encrypt(req);
+ ret = crypto_aead_encrypt(aead_req);
else
- ret = crypto_skcipher_decrypt(req);
-
- skcipher_request_zero(req);
-
+ ret = crypto_aead_decrypt(aead_req);
error:
+ mutex_unlock(&big_key_aead_lock);
+ aead_request_free(aead_req);
return ret;
}
@@ -146,16 +157,13 @@ int big_key_preparse(struct key_preparsed_payload *prep)
*
* File content is stored encrypted with randomly generated key.
*/
- size_t enclen = ALIGN(datalen, crypto_skcipher_blocksize(big_key_skcipher));
+ size_t enclen = datalen + ENC_AUTHTAG_SIZE;
loff_t pos = 0;
- /* prepare aligned data to encrypt */
data = kmalloc(enclen, GFP_KERNEL);
if (!data)
return -ENOMEM;
-
memcpy(data, prep->data, datalen);
- memset(data + datalen, 0x00, enclen - datalen);
/* generate random key */
enckey = kmalloc(ENC_KEY_SIZE, GFP_KERNEL);
@@ -163,13 +171,12 @@ int big_key_preparse(struct key_preparsed_payload *prep)
ret = -ENOMEM;
goto error;
}
-
- ret = big_key_gen_enckey(enckey);
- if (ret)
+ ret = get_random_bytes_wait(enckey, ENC_KEY_SIZE);
+ if (unlikely(ret))
goto err_enckey;
/* encrypt aligned data */
- ret = big_key_crypt(BIG_KEY_ENC, data, enclen, enckey);
+ ret = big_key_crypt(BIG_KEY_ENC, data, datalen, enckey);
if (ret)
goto err_enckey;
@@ -195,7 +202,7 @@ int big_key_preparse(struct key_preparsed_payload *prep)
*path = file->f_path;
path_get(path);
fput(file);
- kfree(data);
+ kzfree(data);
} else {
/* Just store the data in a buffer */
void *data = kmalloc(datalen, GFP_KERNEL);
@@ -211,9 +218,9 @@ int big_key_preparse(struct key_preparsed_payload *prep)
err_fput:
fput(file);
err_enckey:
- kfree(enckey);
+ kzfree(enckey);
error:
- kfree(data);
+ kzfree(data);
return ret;
}
@@ -227,7 +234,7 @@ void big_key_free_preparse(struct key_preparsed_payload *prep)
path_put(path);
}
- kfree(prep->payload.data[big_key_data]);
+ kzfree(prep->payload.data[big_key_data]);
}
/*
@@ -259,7 +266,7 @@ void big_key_destroy(struct key *key)
path->mnt = NULL;
path->dentry = NULL;
}
- kfree(key->payload.data[big_key_data]);
+ kzfree(key->payload.data[big_key_data]);
key->payload.data[big_key_data] = NULL;
}
@@ -295,7 +302,7 @@ long big_key_read(const struct key *key, char __user *buffer, size_t buflen)
struct file *file;
u8 *data;
u8 *enckey = (u8 *)key->payload.data[big_key_data];
- size_t enclen = ALIGN(datalen, crypto_skcipher_blocksize(big_key_skcipher));
+ size_t enclen = datalen + ENC_AUTHTAG_SIZE;
loff_t pos = 0;
data = kmalloc(enclen, GFP_KERNEL);
@@ -328,7 +335,7 @@ long big_key_read(const struct key *key, char __user *buffer, size_t buflen)
err_fput:
fput(file);
error:
- kfree(data);
+ kzfree(data);
} else {
ret = datalen;
if (copy_to_user(buffer, key->payload.data[big_key_data],
@@ -344,47 +351,31 @@ error:
*/
static int __init big_key_init(void)
{
- struct crypto_skcipher *cipher;
- struct crypto_rng *rng;
int ret;
- rng = crypto_alloc_rng(big_key_rng_name, 0, 0);
- if (IS_ERR(rng)) {
- pr_err("Can't alloc rng: %ld\n", PTR_ERR(rng));
- return PTR_ERR(rng);
- }
-
- big_key_rng = rng;
-
- /* seed RNG */
- ret = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
- if (ret) {
- pr_err("Can't reset rng: %d\n", ret);
- goto error_rng;
- }
-
/* init block cipher */
- cipher = crypto_alloc_skcipher(big_key_alg_name, 0, CRYPTO_ALG_ASYNC);
- if (IS_ERR(cipher)) {
- ret = PTR_ERR(cipher);
+ big_key_aead = crypto_alloc_aead(big_key_alg_name, 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(big_key_aead)) {
+ ret = PTR_ERR(big_key_aead);
pr_err("Can't alloc crypto: %d\n", ret);
- goto error_rng;
+ return ret;
+ }
+ ret = crypto_aead_setauthsize(big_key_aead, ENC_AUTHTAG_SIZE);
+ if (ret < 0) {
+ pr_err("Can't set crypto auth tag len: %d\n", ret);
+ goto free_aead;
}
-
- big_key_skcipher = cipher;
ret = register_key_type(&key_type_big_key);
if (ret < 0) {
pr_err("Can't register type: %d\n", ret);
- goto error_cipher;
+ goto free_aead;
}
return 0;
-error_cipher:
- crypto_free_skcipher(big_key_skcipher);
-error_rng:
- crypto_free_rng(big_key_rng);
+free_aead:
+ crypto_free_aead(big_key_aead);
return ret;
}
diff --git a/security/keys/internal.h b/security/keys/internal.h
index 1c02c6547038..503adbae7b0d 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -141,7 +141,7 @@ extern key_ref_t keyring_search_aux(key_ref_t keyring_ref,
extern key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx);
extern key_ref_t search_process_keyrings(struct keyring_search_context *ctx);
-extern struct key *find_keyring_by_name(const char *name, bool skip_perm_check);
+extern struct key *find_keyring_by_name(const char *name, bool uid_keyring);
extern int install_user_keyrings(void);
extern int install_thread_keyring_to_cred(struct cred *);
diff --git a/security/keys/key.c b/security/keys/key.c
index 83da68d98b40..eb914a838840 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -54,10 +54,10 @@ void __key_check(const struct key *key)
struct key_user *key_user_lookup(kuid_t uid)
{
struct key_user *candidate = NULL, *user;
- struct rb_node *parent = NULL;
- struct rb_node **p;
+ struct rb_node *parent, **p;
try_again:
+ parent = NULL;
p = &key_user_tree.rb_node;
spin_lock(&key_user_lock);
@@ -302,6 +302,8 @@ struct key *key_alloc(struct key_type *type, const char *desc,
key->flags |= 1 << KEY_FLAG_IN_QUOTA;
if (flags & KEY_ALLOC_BUILT_IN)
key->flags |= 1 << KEY_FLAG_BUILTIN;
+ if (flags & KEY_ALLOC_UID_KEYRING)
+ key->flags |= 1 << KEY_FLAG_UID_KEYRING;
#ifdef KEY_DEBUGGING
key->magic = KEY_DEBUG_MAGIC;
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index ab0b337c84b4..365ff85d7e27 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -766,12 +766,17 @@ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
key = key_ref_to_ptr(key_ref);
+ if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) {
+ ret = -ENOKEY;
+ goto error2;
+ }
+
/* see if we can read it directly */
ret = key_permission(key_ref, KEY_NEED_READ);
if (ret == 0)
goto can_read_key;
if (ret != -EACCES)
- goto error;
+ goto error2;
/* we can't; see if it's searchable from this process's keyrings
* - we automatically take account of the fact that it may be
@@ -1406,11 +1411,9 @@ long keyctl_assume_authority(key_serial_t id)
}
ret = keyctl_change_reqkey_auth(authkey);
- if (ret < 0)
- goto error;
+ if (ret == 0)
+ ret = authkey->serial;
key_put(authkey);
-
- ret = authkey->serial;
error:
return ret;
}
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index de81793f9920..4fa82a8a9c0e 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -423,7 +423,7 @@ static void keyring_describe(const struct key *keyring, struct seq_file *m)
}
struct keyring_read_iterator_context {
- size_t qty;
+ size_t buflen;
size_t count;
key_serial_t __user *buffer;
};
@@ -435,9 +435,9 @@ static int keyring_read_iterator(const void *object, void *data)
int ret;
kenter("{%s,%d},,{%zu/%zu}",
- key->type->name, key->serial, ctx->count, ctx->qty);
+ key->type->name, key->serial, ctx->count, ctx->buflen);
- if (ctx->count >= ctx->qty)
+ if (ctx->count >= ctx->buflen)
return 1;
ret = put_user(key->serial, ctx->buffer);
@@ -472,16 +472,12 @@ static long keyring_read(const struct key *keyring,
return 0;
/* Calculate how much data we could return */
- ctx.qty = nr_keys * sizeof(key_serial_t);
-
if (!buffer || !buflen)
- return ctx.qty;
-
- if (buflen > ctx.qty)
- ctx.qty = buflen;
+ return nr_keys * sizeof(key_serial_t);
/* Copy the IDs of the subscribed keys into the buffer */
ctx.buffer = (key_serial_t __user *)buffer;
+ ctx.buflen = buflen;
ctx.count = 0;
ret = assoc_array_iterate(&keyring->keys, keyring_read_iterator, &ctx);
if (ret < 0) {
@@ -1101,15 +1097,15 @@ found:
/*
* Find a keyring with the specified name.
*
- * All named keyrings in the current user namespace are searched, provided they
- * grant Search permission directly to the caller (unless this check is
- * skipped). Keyrings whose usage points have reached zero or who have been
- * revoked are skipped.
+ * Only keyrings that have nonzero refcount, are not revoked, and are owned by a
+ * user in the current user namespace are considered. If @uid_keyring is %true,
+ * the keyring additionally must have been allocated as a user or user session
+ * keyring; otherwise, it must grant Search permission directly to the caller.
*
* Returns a pointer to the keyring with the keyring's refcount having being
* incremented on success. -ENOKEY is returned if a key could not be found.
*/
-struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
+struct key *find_keyring_by_name(const char *name, bool uid_keyring)
{
struct key *keyring;
int bucket;
@@ -1137,10 +1133,15 @@ struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
if (strcmp(keyring->description, name) != 0)
continue;
- if (!skip_perm_check &&
- key_permission(make_key_ref(keyring, 0),
- KEY_NEED_SEARCH) < 0)
- continue;
+ if (uid_keyring) {
+ if (!test_bit(KEY_FLAG_UID_KEYRING,
+ &keyring->flags))
+ continue;
+ } else {
+ if (key_permission(make_key_ref(keyring, 0),
+ KEY_NEED_SEARCH) < 0)
+ continue;
+ }
/* we've got a match but we might end up racing with
* key_cleanup() if the keyring is currently 'dead'
diff --git a/security/keys/proc.c b/security/keys/proc.c
index bf08d02b6646..de834309d100 100644
--- a/security/keys/proc.c
+++ b/security/keys/proc.c
@@ -187,7 +187,7 @@ static int proc_keys_show(struct seq_file *m, void *v)
struct keyring_search_context ctx = {
.index_key.type = key->type,
.index_key.description = key->description,
- .cred = current_cred(),
+ .cred = m->file->f_cred,
.match_data.cmp = lookup_user_key_possessed,
.match_data.raw_data = key,
.match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
@@ -207,11 +207,7 @@ static int proc_keys_show(struct seq_file *m, void *v)
}
}
- /* check whether the current task is allowed to view the key (assuming
- * non-possession)
- * - the caller holds a spinlock, and thus the RCU read lock, making our
- * access to __current_cred() safe
- */
+ /* check whether the current task is allowed to view the key */
rc = key_task_permission(key_ref, ctx.cred, KEY_NEED_VIEW);
if (rc < 0)
return 0;
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 86bced9fdbdf..293d3598153b 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -77,7 +77,8 @@ int install_user_keyrings(void)
if (IS_ERR(uid_keyring)) {
uid_keyring = keyring_alloc(buf, user->uid, INVALID_GID,
cred, user_keyring_perm,
- KEY_ALLOC_IN_QUOTA,
+ KEY_ALLOC_UID_KEYRING |
+ KEY_ALLOC_IN_QUOTA,
NULL, NULL);
if (IS_ERR(uid_keyring)) {
ret = PTR_ERR(uid_keyring);
@@ -94,7 +95,8 @@ int install_user_keyrings(void)
session_keyring =
keyring_alloc(buf, user->uid, INVALID_GID,
cred, user_keyring_perm,
- KEY_ALLOC_IN_QUOTA,
+ KEY_ALLOC_UID_KEYRING |
+ KEY_ALLOC_IN_QUOTA,
NULL, NULL);
if (IS_ERR(session_keyring)) {
ret = PTR_ERR(session_keyring);
diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c
index afe9d22ab361..6ebf1af8fce9 100644
--- a/security/keys/request_key_auth.c
+++ b/security/keys/request_key_auth.c
@@ -120,6 +120,18 @@ static void request_key_auth_revoke(struct key *key)
}
}
+static void free_request_key_auth(struct request_key_auth *rka)
+{
+ if (!rka)
+ return;
+ key_put(rka->target_key);
+ key_put(rka->dest_keyring);
+ if (rka->cred)
+ put_cred(rka->cred);
+ kfree(rka->callout_info);
+ kfree(rka);
+}
+
/*
* Destroy an instantiation authorisation token key.
*/
@@ -129,15 +141,7 @@ static void request_key_auth_destroy(struct key *key)
kenter("{%d}", key->serial);
- if (rka->cred) {
- put_cred(rka->cred);
- rka->cred = NULL;
- }
-
- key_put(rka->target_key);
- key_put(rka->dest_keyring);
- kfree(rka->callout_info);
- kfree(rka);
+ free_request_key_auth(rka);
}
/*
@@ -151,22 +155,18 @@ struct key *request_key_auth_new(struct key *target, const void *callout_info,
const struct cred *cred = current->cred;
struct key *authkey = NULL;
char desc[20];
- int ret;
+ int ret = -ENOMEM;
kenter("%d,", target->serial);
/* allocate a auth record */
- rka = kmalloc(sizeof(*rka), GFP_KERNEL);
- if (!rka) {
- kleave(" = -ENOMEM");
- return ERR_PTR(-ENOMEM);
- }
- rka->callout_info = kmalloc(callout_len, GFP_KERNEL);
- if (!rka->callout_info) {
- kleave(" = -ENOMEM");
- kfree(rka);
- return ERR_PTR(-ENOMEM);
- }
+ rka = kzalloc(sizeof(*rka), GFP_KERNEL);
+ if (!rka)
+ goto error;
+ rka->callout_info = kmemdup(callout_info, callout_len, GFP_KERNEL);
+ if (!rka->callout_info)
+ goto error_free_rka;
+ rka->callout_len = callout_len;
/* see if the calling process is already servicing the key request of
* another process */
@@ -176,8 +176,12 @@ struct key *request_key_auth_new(struct key *target, const void *callout_info,
/* if the auth key has been revoked, then the key we're
* servicing is already instantiated */
- if (test_bit(KEY_FLAG_REVOKED, &cred->request_key_auth->flags))
- goto auth_key_revoked;
+ if (test_bit(KEY_FLAG_REVOKED,
+ &cred->request_key_auth->flags)) {
+ up_read(&cred->request_key_auth->sem);
+ ret = -EKEYREVOKED;
+ goto error_free_rka;
+ }
irka = cred->request_key_auth->payload.data[0];
rka->cred = get_cred(irka->cred);
@@ -193,8 +197,6 @@ struct key *request_key_auth_new(struct key *target, const void *callout_info,
rka->target_key = key_get(target);
rka->dest_keyring = key_get(dest_keyring);
- memcpy(rka->callout_info, callout_info, callout_len);
- rka->callout_len = callout_len;
/* allocate the auth key */
sprintf(desc, "%x", target->serial);
@@ -205,32 +207,22 @@ struct key *request_key_auth_new(struct key *target, const void *callout_info,
KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA, NULL);
if (IS_ERR(authkey)) {
ret = PTR_ERR(authkey);
- goto error_alloc;
+ goto error_free_rka;
}
/* construct the auth key */
ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL);
if (ret < 0)
- goto error_inst;
+ goto error_put_authkey;
kleave(" = {%d,%d}", authkey->serial, refcount_read(&authkey->usage));
return authkey;
-auth_key_revoked:
- up_read(&cred->request_key_auth->sem);
- kfree(rka->callout_info);
- kfree(rka);
- kleave("= -EKEYREVOKED");
- return ERR_PTR(-EKEYREVOKED);
-
-error_inst:
- key_revoke(authkey);
+error_put_authkey:
key_put(authkey);
-error_alloc:
- key_put(rka->target_key);
- key_put(rka->dest_keyring);
- kfree(rka->callout_info);
- kfree(rka);
+error_free_rka:
+ free_request_key_auth(rka);
+error:
kleave("= %d", ret);
return ERR_PTR(ret);
}