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-rw-r--r--security/keys/Kconfig2
-rw-r--r--security/keys/Makefile3
-rw-r--r--security/keys/compat.c9
-rw-r--r--security/keys/compat_dh.c38
-rw-r--r--security/keys/dh.c220
-rw-r--r--security/keys/gc.c13
-rw-r--r--security/keys/internal.h32
-rw-r--r--security/keys/key.c58
-rw-r--r--security/keys/keyctl.c60
-rw-r--r--security/keys/keyring.c187
-rw-r--r--security/keys/proc.c4
-rw-r--r--security/keys/process_keys.c2
-rw-r--r--security/keys/request_key_auth.c2
13 files changed, 567 insertions, 63 deletions
diff --git a/security/keys/Kconfig b/security/keys/Kconfig
index d942c7c2bc0a..6fd95f76bfae 100644
--- a/security/keys/Kconfig
+++ b/security/keys/Kconfig
@@ -90,6 +90,8 @@ config KEY_DH_OPERATIONS
bool "Diffie-Hellman operations on retained keys"
depends on KEYS
select MPILIB
+ select CRYPTO
+ select CRYPTO_HASH
help
This option provides support for calculating Diffie-Hellman
public keys and shared secrets using values stored as keys
diff --git a/security/keys/Makefile b/security/keys/Makefile
index 1fd4a16e6daf..57dff0c15809 100644
--- a/security/keys/Makefile
+++ b/security/keys/Makefile
@@ -15,7 +15,8 @@ obj-y := \
request_key.o \
request_key_auth.o \
user_defined.o
-obj-$(CONFIG_KEYS_COMPAT) += compat.o
+compat-obj-$(CONFIG_KEY_DH_OPERATIONS) += compat_dh.o
+obj-$(CONFIG_KEYS_COMPAT) += compat.o $(compat-obj-y)
obj-$(CONFIG_PROC_FS) += proc.o
obj-$(CONFIG_SYSCTL) += sysctl.o
obj-$(CONFIG_PERSISTENT_KEYRINGS) += persistent.o
diff --git a/security/keys/compat.c b/security/keys/compat.c
index 36c80bf5b89c..e87c89c0177c 100644
--- a/security/keys/compat.c
+++ b/security/keys/compat.c
@@ -133,8 +133,13 @@ COMPAT_SYSCALL_DEFINE5(keyctl, u32, option,
return keyctl_get_persistent(arg2, arg3);
case KEYCTL_DH_COMPUTE:
- return keyctl_dh_compute(compat_ptr(arg2), compat_ptr(arg3),
- arg4, compat_ptr(arg5));
+ return compat_keyctl_dh_compute(compat_ptr(arg2),
+ compat_ptr(arg3),
+ arg4, compat_ptr(arg5));
+
+ case KEYCTL_RESTRICT_KEYRING:
+ return keyctl_restrict_keyring(arg2, compat_ptr(arg3),
+ compat_ptr(arg4));
default:
return -EOPNOTSUPP;
diff --git a/security/keys/compat_dh.c b/security/keys/compat_dh.c
new file mode 100644
index 000000000000..a6a659b6bcb6
--- /dev/null
+++ b/security/keys/compat_dh.c
@@ -0,0 +1,38 @@
+/* 32-bit compatibility syscall for 64-bit systems for DH operations
+ *
+ * Copyright (C) 2016 Stephan Mueller <smueller@chronox.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/uaccess.h>
+
+#include "internal.h"
+
+/*
+ * Perform the DH computation or DH based key derivation.
+ *
+ * If successful, 0 will be returned.
+ */
+long compat_keyctl_dh_compute(struct keyctl_dh_params __user *params,
+ char __user *buffer, size_t buflen,
+ struct compat_keyctl_kdf_params __user *kdf)
+{
+ struct keyctl_kdf_params kdfcopy;
+ struct compat_keyctl_kdf_params compat_kdfcopy;
+
+ if (!kdf)
+ return __keyctl_dh_compute(params, buffer, buflen, NULL);
+
+ if (copy_from_user(&compat_kdfcopy, kdf, sizeof(compat_kdfcopy)) != 0)
+ return -EFAULT;
+
+ kdfcopy.hashname = compat_ptr(compat_kdfcopy.hashname);
+ kdfcopy.otherinfo = compat_ptr(compat_kdfcopy.otherinfo);
+ kdfcopy.otherinfolen = compat_kdfcopy.otherinfolen;
+
+ return __keyctl_dh_compute(params, buffer, buflen, &kdfcopy);
+}
diff --git a/security/keys/dh.c b/security/keys/dh.c
index 893af4c45038..e603bd912e4c 100644
--- a/security/keys/dh.c
+++ b/security/keys/dh.c
@@ -11,6 +11,8 @@
#include <linux/mpi.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
+#include <linux/crypto.h>
+#include <crypto/hash.h>
#include <keys/user-type.h>
#include "internal.h"
@@ -77,9 +79,146 @@ error:
return ret;
}
-long keyctl_dh_compute(struct keyctl_dh_params __user *params,
- char __user *buffer, size_t buflen,
- void __user *reserved)
+struct kdf_sdesc {
+ struct shash_desc shash;
+ char ctx[];
+};
+
+static int kdf_alloc(struct kdf_sdesc **sdesc_ret, char *hashname)
+{
+ struct crypto_shash *tfm;
+ struct kdf_sdesc *sdesc;
+ int size;
+
+ /* allocate synchronous hash */
+ tfm = crypto_alloc_shash(hashname, 0, 0);
+ if (IS_ERR(tfm)) {
+ pr_info("could not allocate digest TFM handle %s\n", hashname);
+ return PTR_ERR(tfm);
+ }
+
+ size = sizeof(struct shash_desc) + crypto_shash_descsize(tfm);
+ sdesc = kmalloc(size, GFP_KERNEL);
+ if (!sdesc)
+ return -ENOMEM;
+ sdesc->shash.tfm = tfm;
+ sdesc->shash.flags = 0x0;
+
+ *sdesc_ret = sdesc;
+
+ return 0;
+}
+
+static void kdf_dealloc(struct kdf_sdesc *sdesc)
+{
+ if (!sdesc)
+ return;
+
+ if (sdesc->shash.tfm)
+ crypto_free_shash(sdesc->shash.tfm);
+
+ kzfree(sdesc);
+}
+
+/* convert 32 bit integer into its string representation */
+static inline void crypto_kw_cpu_to_be32(u32 val, u8 *buf)
+{
+ __be32 *a = (__be32 *)buf;
+
+ *a = cpu_to_be32(val);
+}
+
+/*
+ * Implementation of the KDF in counter mode according to SP800-108 section 5.1
+ * as well as SP800-56A section 5.8.1 (Single-step KDF).
+ *
+ * SP800-56A:
+ * The src pointer is defined as Z || other info where Z is the shared secret
+ * from DH and other info is an arbitrary string (see SP800-56A section
+ * 5.8.1.2).
+ */
+static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen,
+ u8 *dst, unsigned int dlen)
+{
+ struct shash_desc *desc = &sdesc->shash;
+ unsigned int h = crypto_shash_digestsize(desc->tfm);
+ int err = 0;
+ u8 *dst_orig = dst;
+ u32 i = 1;
+ u8 iteration[sizeof(u32)];
+
+ while (dlen) {
+ err = crypto_shash_init(desc);
+ if (err)
+ goto err;
+
+ crypto_kw_cpu_to_be32(i, iteration);
+ err = crypto_shash_update(desc, iteration, sizeof(u32));
+ if (err)
+ goto err;
+
+ if (src && slen) {
+ err = crypto_shash_update(desc, src, slen);
+ if (err)
+ goto err;
+ }
+
+ if (dlen < h) {
+ u8 tmpbuffer[h];
+
+ err = crypto_shash_final(desc, tmpbuffer);
+ if (err)
+ goto err;
+ memcpy(dst, tmpbuffer, dlen);
+ memzero_explicit(tmpbuffer, h);
+ return 0;
+ } else {
+ err = crypto_shash_final(desc, dst);
+ if (err)
+ goto err;
+
+ dlen -= h;
+ dst += h;
+ i++;
+ }
+ }
+
+ return 0;
+
+err:
+ memzero_explicit(dst_orig, dlen);
+ return err;
+}
+
+static int keyctl_dh_compute_kdf(struct kdf_sdesc *sdesc,
+ char __user *buffer, size_t buflen,
+ uint8_t *kbuf, size_t kbuflen)
+{
+ uint8_t *outbuf = NULL;
+ int ret;
+
+ outbuf = kmalloc(buflen, GFP_KERNEL);
+ if (!outbuf) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ ret = kdf_ctr(sdesc, kbuf, kbuflen, outbuf, buflen);
+ if (ret)
+ goto err;
+
+ ret = buflen;
+ if (copy_to_user(buffer, outbuf, buflen) != 0)
+ ret = -EFAULT;
+
+err:
+ kzfree(outbuf);
+ return ret;
+}
+
+long __keyctl_dh_compute(struct keyctl_dh_params __user *params,
+ char __user *buffer, size_t buflen,
+ struct keyctl_kdf_params *kdfcopy)
{
long ret;
MPI base, private, prime, result;
@@ -88,6 +227,7 @@ long keyctl_dh_compute(struct keyctl_dh_params __user *params,
uint8_t *kbuf;
ssize_t keylen;
size_t resultlen;
+ struct kdf_sdesc *sdesc = NULL;
if (!params || (!buffer && buflen)) {
ret = -EINVAL;
@@ -98,12 +238,34 @@ long keyctl_dh_compute(struct keyctl_dh_params __user *params,
goto out;
}
- if (reserved) {
- ret = -EINVAL;
- goto out;
+ if (kdfcopy) {
+ char *hashname;
+
+ if (buflen > KEYCTL_KDF_MAX_OUTPUT_LEN ||
+ kdfcopy->otherinfolen > KEYCTL_KDF_MAX_OI_LEN) {
+ ret = -EMSGSIZE;
+ goto out;
+ }
+
+ /* get KDF name string */
+ hashname = strndup_user(kdfcopy->hashname, CRYPTO_MAX_ALG_NAME);
+ if (IS_ERR(hashname)) {
+ ret = PTR_ERR(hashname);
+ goto out;
+ }
+
+ /* allocate KDF from the kernel crypto API */
+ ret = kdf_alloc(&sdesc, hashname);
+ kfree(hashname);
+ if (ret)
+ goto out;
}
- keylen = mpi_from_key(pcopy.prime, buflen, &prime);
+ /*
+ * If the caller requests postprocessing with a KDF, allow an
+ * arbitrary output buffer size since the KDF ensures proper truncation.
+ */
+ keylen = mpi_from_key(pcopy.prime, kdfcopy ? SIZE_MAX : buflen, &prime);
if (keylen < 0 || !prime) {
/* buflen == 0 may be used to query the required buffer size,
* which is the prime key length.
@@ -133,12 +295,25 @@ long keyctl_dh_compute(struct keyctl_dh_params __user *params,
goto error3;
}
- kbuf = kmalloc(resultlen, GFP_KERNEL);
+ /* allocate space for DH shared secret and SP800-56A otherinfo */
+ kbuf = kmalloc(kdfcopy ? (resultlen + kdfcopy->otherinfolen) : resultlen,
+ GFP_KERNEL);
if (!kbuf) {
ret = -ENOMEM;
goto error4;
}
+ /*
+ * Concatenate SP800-56A otherinfo past DH shared secret -- the
+ * input to the KDF is (DH shared secret || otherinfo)
+ */
+ if (kdfcopy && kdfcopy->otherinfo &&
+ copy_from_user(kbuf + resultlen, kdfcopy->otherinfo,
+ kdfcopy->otherinfolen) != 0) {
+ ret = -EFAULT;
+ goto error5;
+ }
+
ret = do_dh(result, base, private, prime);
if (ret)
goto error5;
@@ -147,12 +322,17 @@ long keyctl_dh_compute(struct keyctl_dh_params __user *params,
if (ret != 0)
goto error5;
- ret = nbytes;
- if (copy_to_user(buffer, kbuf, nbytes) != 0)
- ret = -EFAULT;
+ if (kdfcopy) {
+ ret = keyctl_dh_compute_kdf(sdesc, buffer, buflen, kbuf,
+ resultlen + kdfcopy->otherinfolen);
+ } else {
+ ret = nbytes;
+ if (copy_to_user(buffer, kbuf, nbytes) != 0)
+ ret = -EFAULT;
+ }
error5:
- kfree(kbuf);
+ kzfree(kbuf);
error4:
mpi_free(result);
error3:
@@ -162,5 +342,21 @@ error2:
error1:
mpi_free(prime);
out:
+ kdf_dealloc(sdesc);
return ret;
}
+
+long keyctl_dh_compute(struct keyctl_dh_params __user *params,
+ char __user *buffer, size_t buflen,
+ struct keyctl_kdf_params __user *kdf)
+{
+ struct keyctl_kdf_params kdfcopy;
+
+ if (!kdf)
+ return __keyctl_dh_compute(params, buffer, buflen, NULL);
+
+ if (copy_from_user(&kdfcopy, kdf, sizeof(kdfcopy)) != 0)
+ return -EFAULT;
+
+ return __keyctl_dh_compute(params, buffer, buflen, &kdfcopy);
+}
diff --git a/security/keys/gc.c b/security/keys/gc.c
index 9cb4fe4478a1..595becc6d0d2 100644
--- a/security/keys/gc.c
+++ b/security/keys/gc.c
@@ -220,7 +220,7 @@ continue_scanning:
key = rb_entry(cursor, struct key, serial_node);
cursor = rb_next(cursor);
- if (atomic_read(&key->usage) == 0)
+ if (refcount_read(&key->usage) == 0)
goto found_unreferenced_key;
if (unlikely(gc_state & KEY_GC_REAPING_DEAD_1)) {
@@ -229,6 +229,9 @@ continue_scanning:
set_bit(KEY_FLAG_DEAD, &key->flags);
key->perm = 0;
goto skip_dead_key;
+ } else if (key->type == &key_type_keyring &&
+ key->restrict_link) {
+ goto found_restricted_keyring;
}
}
@@ -334,6 +337,14 @@ found_unreferenced_key:
gc_state |= KEY_GC_REAP_AGAIN;
goto maybe_resched;
+ /* We found a restricted keyring and need to update the restriction if
+ * it is associated with the dead key type.
+ */
+found_restricted_keyring:
+ spin_unlock(&key_serial_lock);
+ keyring_restriction_gc(key, key_gc_dead_keytype);
+ goto maybe_resched;
+
/* We found a keyring and we need to check the payload for links to
* dead or expired keys. We don't flag another reap immediately as we
* have to wait for the old payload to be destroyed by RCU before we
diff --git a/security/keys/internal.h b/security/keys/internal.h
index a2f4c0abb8d8..c0f8682eba69 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -17,6 +17,8 @@
#include <linux/key-type.h>
#include <linux/task_work.h>
#include <linux/keyctl.h>
+#include <linux/refcount.h>
+#include <linux/compat.h>
struct iovec;
@@ -53,7 +55,7 @@ struct key_user {
struct rb_node node;
struct mutex cons_lock; /* construction initiation lock */
spinlock_t lock;
- atomic_t usage; /* for accessing qnkeys & qnbytes */
+ refcount_t usage; /* for accessing qnkeys & qnbytes */
atomic_t nkeys; /* number of keys */
atomic_t nikeys; /* number of instantiated keys */
kuid_t uid;
@@ -167,6 +169,8 @@ extern void key_change_session_keyring(struct callback_head *twork);
extern struct work_struct key_gc_work;
extern unsigned key_gc_delay;
extern void keyring_gc(struct key *keyring, time_t limit);
+extern void keyring_restriction_gc(struct key *keyring,
+ struct key_type *dead_type);
extern void key_schedule_gc(time_t gc_at);
extern void key_schedule_gc_links(void);
extern void key_gc_keytype(struct key_type *ktype);
@@ -249,6 +253,9 @@ struct iov_iter;
extern long keyctl_instantiate_key_common(key_serial_t,
struct iov_iter *,
key_serial_t);
+extern long keyctl_restrict_keyring(key_serial_t id,
+ const char __user *_type,
+ const char __user *_restriction);
#ifdef CONFIG_PERSISTENT_KEYRINGS
extern long keyctl_get_persistent(uid_t, key_serial_t);
extern unsigned persistent_keyring_expiry;
@@ -261,15 +268,34 @@ static inline long keyctl_get_persistent(uid_t uid, key_serial_t destring)
#ifdef CONFIG_KEY_DH_OPERATIONS
extern long keyctl_dh_compute(struct keyctl_dh_params __user *, char __user *,
- size_t, void __user *);
+ size_t, struct keyctl_kdf_params __user *);
+extern long __keyctl_dh_compute(struct keyctl_dh_params __user *, char __user *,
+ size_t, struct keyctl_kdf_params *);
+#ifdef CONFIG_KEYS_COMPAT
+extern long compat_keyctl_dh_compute(struct keyctl_dh_params __user *params,
+ char __user *buffer, size_t buflen,
+ struct compat_keyctl_kdf_params __user *kdf);
+#endif
+#define KEYCTL_KDF_MAX_OUTPUT_LEN 1024 /* max length of KDF output */
+#define KEYCTL_KDF_MAX_OI_LEN 64 /* max length of otherinfo */
#else
static inline long keyctl_dh_compute(struct keyctl_dh_params __user *params,
char __user *buffer, size_t buflen,
- void __user *reserved)
+ struct keyctl_kdf_params __user *kdf)
+{
+ return -EOPNOTSUPP;
+}
+
+#ifdef CONFIG_KEYS_COMPAT
+static inline long compat_keyctl_dh_compute(
+ struct keyctl_dh_params __user *params,
+ char __user *buffer, size_t buflen,
+ struct keyctl_kdf_params __user *kdf)
{
return -EOPNOTSUPP;
}
#endif
+#endif
/*
* Debugging key validation
diff --git a/security/keys/key.c b/security/keys/key.c
index 346fbf201c22..455c04d80bbb 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -93,7 +93,7 @@ try_again:
/* if we get here, then the user record still hadn't appeared on the
* second pass - so we use the candidate record */
- atomic_set(&candidate->usage, 1);
+ refcount_set(&candidate->usage, 1);
atomic_set(&candidate->nkeys, 0);
atomic_set(&candidate->nikeys, 0);
candidate->uid = uid;
@@ -110,7 +110,7 @@ try_again:
/* okay - we found a user record for this UID */
found:
- atomic_inc(&user->usage);
+ refcount_inc(&user->usage);
spin_unlock(&key_user_lock);
kfree(candidate);
out:
@@ -122,7 +122,7 @@ out:
*/
void key_user_put(struct key_user *user)
{
- if (atomic_dec_and_lock(&user->usage, &key_user_lock)) {
+ if (refcount_dec_and_lock(&user->usage, &key_user_lock)) {
rb_erase(&user->node, &key_user_tree);
spin_unlock(&key_user_lock);
@@ -201,12 +201,15 @@ serial_exists:
* @cred: The credentials specifying UID namespace.
* @perm: The permissions mask of the new key.
* @flags: Flags specifying quota properties.
- * @restrict_link: Optional link restriction method for new keyrings.
+ * @restrict_link: Optional link restriction for new keyrings.
*
* Allocate a key of the specified type with the attributes given. The key is
* returned in an uninstantiated state and the caller needs to instantiate the
* key before returning.
*
+ * The restrict_link structure (if not NULL) will be freed when the
+ * keyring is destroyed, so it must be dynamically allocated.
+ *
* The user's key count quota is updated to reflect the creation of the key and
* the user's key data quota has the default for the key type reserved. The
* instantiation function should amend this as necessary. If insufficient
@@ -225,9 +228,7 @@ serial_exists:
struct key *key_alloc(struct key_type *type, const char *desc,
kuid_t uid, kgid_t gid, const struct cred *cred,
key_perm_t perm, unsigned long flags,
- int (*restrict_link)(struct key *,
- const struct key_type *,
- const union key_payload *))
+ struct key_restriction *restrict_link)
{
struct key_user *user = NULL;
struct key *key;
@@ -285,7 +286,7 @@ struct key *key_alloc(struct key_type *type, const char *desc,
if (!key->index_key.description)
goto no_memory_3;
- atomic_set(&key->usage, 1);
+ refcount_set(&key->usage, 1);
init_rwsem(&key->sem);
lockdep_set_class(&key->sem, &type->lock_class);
key->index_key.type = type;
@@ -499,19 +500,23 @@ int key_instantiate_and_link(struct key *key,
}
if (keyring) {
- if (keyring->restrict_link) {
- ret = keyring->restrict_link(keyring, key->type,
- &prep.payload);
- if (ret < 0)
- goto error;
- }
ret = __key_link_begin(keyring, &key->index_key, &edit);
if (ret < 0)
goto error;
+
+ if (keyring->restrict_link && keyring->restrict_link->check) {
+ struct key_restriction *keyres = keyring->restrict_link;
+
+ ret = keyres->check(keyring, key->type, &prep.payload,
+ keyres->key);
+ if (ret < 0)
+ goto error_link_end;
+ }
}
ret = __key_instantiate_and_link(key, &prep, keyring, authkey, &edit);
+error_link_end:
if (keyring)
__key_link_end(keyring, &key->index_key, edit);
@@ -621,7 +626,7 @@ void key_put(struct key *key)
if (key) {
key_check(key);
- if (atomic_dec_and_test(&key->usage))
+ if (refcount_dec_and_test(&key->usage))
schedule_work(&key_gc_work);
}
}
@@ -656,7 +661,7 @@ not_found:
found:
/* pretend it doesn't exist if it is awaiting deletion */
- if (atomic_read(&key->usage) == 0)
+ if (refcount_read(&key->usage) == 0)
goto not_found;
/* this races with key_put(), but that doesn't matter since key_put()
@@ -806,9 +811,7 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
struct key *keyring, *key = NULL;
key_ref_t key_ref;
int ret;
- int (*restrict_link)(struct key *,
- const struct key_type *,
- const union key_payload *) = NULL;
+ struct key_restriction *restrict_link = NULL;
/* look up the key type to see if it's one of the registered kernel
* types */
@@ -854,20 +857,21 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
}
index_key.desc_len = strlen(index_key.description);
- if (restrict_link) {
- ret = restrict_link(keyring, index_key.type, &prep.payload);
- if (ret < 0) {
- key_ref = ERR_PTR(ret);
- goto error_free_prep;
- }
- }
-
ret = __key_link_begin(keyring, &index_key, &edit);
if (ret < 0) {
key_ref = ERR_PTR(ret);
goto error_free_prep;
}
+ if (restrict_link && restrict_link->check) {
+ ret = restrict_link->check(keyring, index_key.type,
+ &prep.payload, restrict_link->key);
+ if (ret < 0) {
+ key_ref = ERR_PTR(ret);
+ goto error_link_end;
+ }
+ }
+
/* if we're going to allocate a new key, we're going to have
* to modify the keyring */
ret = key_permission(keyring_ref, KEY_NEED_WRITE);
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 4ad3212adebe..82a9e1851108 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -1585,6 +1585,59 @@ error_keyring:
}
/*
+ * Apply a restriction to a given 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.
+ *
+ * Returns 0 if successful.
+ */
+long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
+ const char __user *_restriction)
+{
+ key_ref_t key_ref;
+ bool link_reject = !_type;
+ char type[32];
+ char *restriction = NULL;
+ long ret;
+
+ key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
+ if (IS_ERR(key_ref))
+ return PTR_ERR(key_ref);
+
+ if (_type) {
+ 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;
+ }
+ }
+
+ ret = keyring_restrict(key_ref, link_reject ? NULL : type, restriction);
+ kfree(restriction);
+
+error:
+ key_ref_put(key_ref);
+
+ return ret;
+}
+
+/*
* The key control system call
*/
SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
@@ -1693,7 +1746,12 @@ SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
case KEYCTL_DH_COMPUTE:
return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
(char __user *) arg3, (size_t) arg4,
- (void __user *) arg5);
+ (struct keyctl_kdf_params __user *) arg5);
+
+ case KEYCTL_RESTRICT_KEYRING:
+ return keyctl_restrict_keyring((key_serial_t) arg2,
+ (const char __user *) arg3,
+ (const char __user *) arg4);
default:
return -EOPNOTSUPP;
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index c91e4e0cea08..4d1678e4586f 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -394,6 +394,13 @@ static void keyring_destroy(struct key *keyring)
write_unlock(&keyring_name_lock);
}
+ if (keyring->restrict_link) {
+ struct key_restriction *keyres = keyring->restrict_link;
+
+ key_put(keyres->key);
+ kfree(keyres);
+ }
+
assoc_array_destroy(&keyring->keys, &keyring_assoc_array_ops);
}
@@ -492,9 +499,7 @@ static long keyring_read(const struct key *keyring,
struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid,
const struct cred *cred, key_perm_t perm,
unsigned long flags,
- int (*restrict_link)(struct key *,
- const struct key_type *,
- const union key_payload *),
+ struct key_restriction *restrict_link,
struct key *dest)
{
struct key *keyring;
@@ -519,17 +524,19 @@ EXPORT_SYMBOL(keyring_alloc);
* @keyring: The keyring being added to.
* @type: The type of key being added.
* @payload: The payload of the key intended to be added.
+ * @data: Additional data for evaluating restriction.
*
* Reject the addition of any links to a keyring. It can be overridden by
* passing KEY_ALLOC_BYPASS_RESTRICTION to key_instantiate_and_link() when
* adding a key to a keyring.
*
- * This is meant to be passed as the restrict_link parameter to
- * keyring_alloc().
+ * This is meant to be stored in a key_restriction structure which is passed
+ * in the restrict_link parameter to keyring_alloc().
*/
int restrict_link_reject(struct key *keyring,
const struct key_type *type,
- const union key_payload *payload)
+ const union key_payload *payload,
+ struct key *restriction_key)
{
return -EPERM;
}
@@ -940,6 +947,111 @@ key_ref_t keyring_search(key_ref_t keyring,
}
EXPORT_SYMBOL(keyring_search);
+static struct key_restriction *keyring_restriction_alloc(
+ key_restrict_link_func_t check)
+{
+ struct key_restriction *keyres =
+ kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
+
+ if (!keyres)
+ return ERR_PTR(-ENOMEM);
+
+ keyres->check = check;
+
+ return keyres;
+}
+
+/*
+ * Semaphore to serialise restriction setup to prevent reference count
+ * cycles through restriction key pointers.
+ */
+static DECLARE_RWSEM(keyring_serialise_restrict_sem);
+
+/*
+ * Check for restriction cycles that would prevent keyring garbage collection.
+ * keyring_serialise_restrict_sem must be held.
+ */
+static bool keyring_detect_restriction_cycle(const struct key *dest_keyring,
+ struct key_restriction *keyres)
+{
+ while (keyres && keyres->key &&
+ keyres->key->type == &key_type_keyring) {
+ if (keyres->key == dest_keyring)
+ return true;
+
+ keyres = keyres->key->restrict_link;
+ }
+
+ return false;
+}
+
+/**
+ * keyring_restrict - Look up and apply a restriction to a keyring
+ *
+ * @keyring: The keyring to be restricted
+ * @restriction: The restriction options to apply to the keyring
+ */
+int keyring_restrict(key_ref_t keyring_ref, const char *type,
+ const char *restriction)
+{
+ struct key *keyring;
+ struct key_type *restrict_type = NULL;
+ struct key_restriction *restrict_link;
+ int ret = 0;
+
+ keyring = key_ref_to_ptr(keyring_ref);
+ key_check(keyring);
+
+ if (keyring->type != &key_type_keyring)
+ return -ENOTDIR;
+
+ if (!type) {
+ restrict_link = keyring_restriction_alloc(restrict_link_reject);
+ } else {
+ restrict_type = key_type_lookup(type);
+
+ if (IS_ERR(restrict_type))
+ return PTR_ERR(restrict_type);
+
+ if (!restrict_type->lookup_restriction) {
+ ret = -ENOENT;
+ goto error;
+ }
+
+ restrict_link = restrict_type->lookup_restriction(restriction);
+ }
+
+ if (IS_ERR(restrict_link)) {
+ ret = PTR_ERR(restrict_link);
+ goto error;
+ }
+
+ down_write(&keyring->sem);
+ down_write(&keyring_serialise_restrict_sem);
+
+ if (keyring->restrict_link)
+ ret = -EEXIST;
+ else if (keyring_detect_restriction_cycle(keyring, restrict_link))
+ ret = -EDEADLK;
+ else
+ keyring->restrict_link = restrict_link;
+
+ up_write(&keyring_serialise_restrict_sem);
+ up_write(&keyring->sem);
+
+ if (ret < 0) {
+ key_put(restrict_link->key);
+ kfree(restrict_link);
+ }
+
+error:
+ if (restrict_type)
+ key_type_put(restrict_type);
+
+ return ret;
+}
+EXPORT_SYMBOL(keyring_restrict);
+
/*
* Search the given keyring for a key that might be updated.
*
@@ -1033,7 +1145,7 @@ struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
/* we've got a match but we might end up racing with
* key_cleanup() if the keyring is currently 'dead'
* (ie. it has a zero usage count) */
- if (!atomic_inc_not_zero(&keyring->usage))
+ if (!refcount_inc_not_zero(&keyring->usage))
continue;
keyring->last_used_at = current_kernel_time().tv_sec;
goto out;
@@ -1220,9 +1332,10 @@ void __key_link_end(struct key *keyring,
*/
static int __key_link_check_restriction(struct key *keyring, struct key *key)
{
- if (!keyring->restrict_link)
+ if (!keyring->restrict_link || !keyring->restrict_link->check)
return 0;
- return keyring->restrict_link(keyring, key->type, &key->payload);
+ return keyring->restrict_link->check(keyring, key->type, &key->payload,
+ keyring->restrict_link->key);
}
/**
@@ -1250,14 +1363,14 @@ int key_link(struct key *keyring, struct key *key)
struct assoc_array_edit *edit;
int ret;
- kenter("{%d,%d}", keyring->serial, atomic_read(&keyring->usage));
+ kenter("{%d,%d}", keyring->serial, refcount_read(&keyring->usage));
key_check(keyring);
key_check(key);
ret = __key_link_begin(keyring, &key->index_key, &edit);
if (ret == 0) {
- kdebug("begun {%d,%d}", keyring->serial, atomic_read(&keyring->usage));
+ kdebug("begun {%d,%d}", keyring->serial, refcount_read(&keyring->usage));
ret = __key_link_check_restriction(keyring, key);
if (ret == 0)
ret = __key_link_check_live_key(keyring, key);
@@ -1266,7 +1379,7 @@ int key_link(struct key *keyring, struct key *key)
__key_link_end(keyring, &key->index_key, edit);
}
- kleave(" = %d {%d,%d}", ret, keyring->serial, atomic_read(&keyring->usage));
+ kleave(" = %d {%d,%d}", ret, keyring->serial, refcount_read(&keyring->usage));
return ret;
}
EXPORT_SYMBOL(key_link);
@@ -1426,3 +1539,53 @@ do_gc:
up_write(&keyring->sem);
kleave(" [gc]");
}
+
+/*
+ * Garbage collect restriction pointers from a keyring.
+ *
+ * Keyring restrictions are associated with a key type, and must be cleaned
+ * up if the key type is unregistered. The restriction is altered to always
+ * reject additional keys so a keyring cannot be opened up by unregistering
+ * a key type.
+ *
+ * Not called with any keyring locks held. The keyring's key struct will not
+ * be deallocated under us as only our caller may deallocate it.
+ *
+ * The caller is required to hold key_types_sem and dead_type->sem. This is
+ * fulfilled by key_gc_keytype() holding the locks on behalf of
+ * key_garbage_collector(), which it invokes on a workqueue.
+ */
+void keyring_restriction_gc(struct key *keyring, struct key_type *dead_type)
+{
+ struct key_restriction *keyres;
+
+ kenter("%x{%s}", keyring->serial, keyring->description ?: "");
+
+ /*
+ * keyring->restrict_link is only assigned at key allocation time
+ * or with the key type locked, so the only values that could be
+ * concurrently assigned to keyring->restrict_link are for key
+ * types other than dead_type. Given this, it's ok to check
+ * the key type before acquiring keyring->sem.
+ */
+ if (!dead_type || !keyring->restrict_link ||
+ keyring->restrict_link->keytype != dead_type) {
+ kleave(" [no restriction gc]");
+ return;
+ }
+
+ /* Lock the keyring to ensure that a link is not in progress */
+ down_write(&keyring->sem);
+
+ keyres = keyring->restrict_link;
+
+ keyres->check = restrict_link_reject;
+
+ key_put(keyres->key);
+ keyres->key = NULL;
+ keyres->keytype = NULL;
+
+ up_write(&keyring->sem);
+
+ kleave(" [restriction gc]");
+}
diff --git a/security/keys/proc.c b/security/keys/proc.c
index b9f531c9e4fa..bf08d02b6646 100644
--- a/security/keys/proc.c
+++ b/security/keys/proc.c
@@ -252,7 +252,7 @@ static int proc_keys_show(struct seq_file *m, void *v)
showflag(key, 'U', KEY_FLAG_USER_CONSTRUCT),
showflag(key, 'N', KEY_FLAG_NEGATIVE),
showflag(key, 'i', KEY_FLAG_INVALIDATED),
- atomic_read(&key->usage),
+ refcount_read(&key->usage),
xbuf,
key->perm,
from_kuid_munged(seq_user_ns(m), key->uid),
@@ -340,7 +340,7 @@ static int proc_key_users_show(struct seq_file *m, void *v)
seq_printf(m, "%5u: %5d %d/%d %d/%d %d/%d\n",
from_kuid_munged(seq_user_ns(m), user->uid),
- atomic_read(&user->usage),
+ refcount_read(&user->usage),
atomic_read(&user->nkeys),
atomic_read(&user->nikeys),
user->qnkeys,
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 9139b18fc863..2217dfec7996 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -30,7 +30,7 @@ static DEFINE_MUTEX(key_user_keyring_mutex);
/* The root user's tracking struct */
struct key_user root_key_user = {
- .usage = ATOMIC_INIT(3),
+ .usage = REFCOUNT_INIT(3),
.cons_lock = __MUTEX_INITIALIZER(root_key_user.cons_lock),
.lock = __SPIN_LOCK_UNLOCKED(root_key_user.lock),
.nkeys = ATOMIC_INIT(2),
diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c
index 6bbe2f535f08..0f062156dfb2 100644
--- a/security/keys/request_key_auth.c
+++ b/security/keys/request_key_auth.c
@@ -213,7 +213,7 @@ struct key *request_key_auth_new(struct key *target, const void *callout_info,
if (ret < 0)
goto error_inst;
- kleave(" = {%d,%d}", authkey->serial, atomic_read(&authkey->usage));
+ kleave(" = {%d,%d}", authkey->serial, refcount_read(&authkey->usage));
return authkey;
auth_key_revoked:
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-14 10:34:52 +0000