From 13923d0865ca96312197962522e88bc0aedccd74 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 9 Oct 2017 12:37:49 -0700 Subject: [PATCH 01/15] KEYS: encrypted: fix dereference of NULL user_key_payload A key of type "encrypted" references a "master key" which is used to encrypt and decrypt the encrypted key's payload. However, when we accessed the master key's payload, we failed to handle the case where the master key has been revoked, which sets the payload pointer to NULL. Note that request_key() *does* skip revoked keys, but there is still a window where the key can be revoked before we acquire its semaphore. Fix it by checking for a NULL payload, treating it like a key which was already revoked at the time it was requested. This was an issue for master keys of type "user" only. Master keys can also be of type "trusted", but those cannot be revoked. Fixes: 7e70cb497850 ("keys: add new key-type encrypted") Reviewed-by: James Morris Cc: [v2.6.38+] Cc: Mimi Zohar Cc: David Safford Signed-off-by: Eric Biggers Signed-off-by: David Howells --- security/keys/encrypted-keys/encrypted.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c index 69855ba0d3b3..535db141f4da 100644 --- a/security/keys/encrypted-keys/encrypted.c +++ b/security/keys/encrypted-keys/encrypted.c @@ -309,6 +309,13 @@ static struct key *request_user_key(const char *master_desc, const u8 **master_k down_read(&ukey->sem); upayload = user_key_payload_locked(ukey); + if (!upayload) { + /* key was revoked before we acquired its semaphore */ + up_read(&ukey->sem); + key_put(ukey); + ukey = ERR_PTR(-EKEYREVOKED); + goto error; + } *master_key = upayload->data; *master_keylen = upayload->datalen; error: From d124b2c53c7bee6569d2a2d0b18b4a1afde00134 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 9 Oct 2017 12:40:00 -0700 Subject: [PATCH 02/15] FS-Cache: fix dereference of NULL user_key_payload When the file /proc/fs/fscache/objects (available with CONFIG_FSCACHE_OBJECT_LIST=y) is opened, we request a user key with description "fscache:objlist", then access its payload. However, a revoked key has a NULL payload, and we failed to check for this. request_key() *does* skip revoked keys, but there is still a window where the key can be revoked before we access its payload. Fix it by checking for a NULL payload, treating it like a key which was already revoked at the time it was requested. Fixes: 4fbf4291aa15 ("FS-Cache: Allow the current state of all objects to be dumped") Reviewed-by: James Morris Cc: [v2.6.32+] Signed-off-by: Eric Biggers Signed-off-by: David Howells --- fs/fscache/object-list.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/fscache/object-list.c b/fs/fscache/object-list.c index b5ab06fabc60..0438d4cd91ef 100644 --- a/fs/fscache/object-list.c +++ b/fs/fscache/object-list.c @@ -331,6 +331,13 @@ static void fscache_objlist_config(struct fscache_objlist_data *data) rcu_read_lock(); confkey = user_key_payload_rcu(key); + if (!confkey) { + /* key was revoked */ + rcu_read_unlock(); + key_put(key); + goto no_config; + } + buf = confkey->data; for (len = confkey->datalen - 1; len >= 0; len--) { From 192cabd6a296cbc57b3d8c05c4c89d87fc102506 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 9 Oct 2017 12:43:20 -0700 Subject: [PATCH 03/15] lib/digsig: fix dereference of NULL user_key_payload digsig_verify() requests a user key, then accesses its payload. However, a revoked key has a NULL payload, and we failed to check for this. request_key() *does* skip revoked keys, but there is still a window where the key can be revoked before we acquire its semaphore. Fix it by checking for a NULL payload, treating it like a key which was already revoked at the time it was requested. Fixes: 051dbb918c7f ("crypto: digital signature verification support") Reviewed-by: James Morris Cc: [v3.3+] Cc: Dmitry Kasatkin Signed-off-by: Eric Biggers Signed-off-by: David Howells --- lib/digsig.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/lib/digsig.c b/lib/digsig.c index 03d7c63837ae..6ba6fcd92dd1 100644 --- a/lib/digsig.c +++ b/lib/digsig.c @@ -87,6 +87,12 @@ static int digsig_verify_rsa(struct key *key, down_read(&key->sem); ukp = user_key_payload_locked(key); + if (!ukp) { + /* key was revoked before we acquired its semaphore */ + err = -EKEYREVOKED; + goto err1; + } + if (ukp->datalen < sizeof(*pkh)) goto err1; From d60b5b7854c3d135b869f74fb93eaf63cbb1991a Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 9 Oct 2017 12:46:18 -0700 Subject: [PATCH 04/15] fscrypt: fix dereference of NULL user_key_payload When an fscrypt-encrypted file is opened, we request the file's master key from the keyrings service as a logon key, then access its payload. However, a revoked key has a NULL payload, and we failed to check for this. request_key() *does* skip revoked keys, but there is still a window where the key can be revoked before we acquire its semaphore. Fix it by checking for a NULL payload, treating it like a key which was already revoked at the time it was requested. Fixes: 88bd6ccdcdd6 ("ext4 crypto: add encryption key management facilities") Reviewed-by: James Morris Cc: [v4.1+] Signed-off-by: Eric Biggers Signed-off-by: David Howells --- fs/crypto/keyinfo.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c index 018c588c7ac3..8e704d12a1cf 100644 --- a/fs/crypto/keyinfo.c +++ b/fs/crypto/keyinfo.c @@ -109,6 +109,11 @@ static int validate_user_key(struct fscrypt_info *crypt_info, goto out; } ukp = user_key_payload_locked(keyring_key); + if (!ukp) { + /* key was revoked before we acquired its semaphore */ + res = -EKEYREVOKED; + goto out; + } if (ukp->datalen != sizeof(struct fscrypt_key)) { res = -EINVAL; goto out; From f66665c09ab489a11ca490d6a82df57cfc1bea3e Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 9 Oct 2017 12:51:27 -0700 Subject: [PATCH 05/15] ecryptfs: fix dereference of NULL user_key_payload In eCryptfs, we failed to verify that the authentication token keys are not revoked before dereferencing their payloads, which is problematic because the payload of a revoked key is NULL. request_key() *does* skip revoked keys, but there is still a window where the key can be revoked before we acquire the key semaphore. Fix it by updating ecryptfs_get_key_payload_data() to return -EKEYREVOKED if the key payload is NULL. For completeness we check this for "encrypted" keys as well as "user" keys, although encrypted keys cannot be revoked currently. Alternatively we could use key_validate(), but since we'll also need to fix ecryptfs_get_key_payload_data() to validate the payload length, it seems appropriate to just check the payload pointer. Fixes: 237fead61998 ("[PATCH] ecryptfs: fs/Makefile and fs/Kconfig") Reviewed-by: James Morris Cc: [v2.6.19+] Cc: Michael Halcrow Signed-off-by: Eric Biggers Signed-off-by: David Howells --- fs/ecryptfs/ecryptfs_kernel.h | 24 +++++++++++++++++------- fs/ecryptfs/keystore.c | 9 ++++++++- 2 files changed, 25 insertions(+), 8 deletions(-) diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h index 9c351bf757b2..3fbc0ff79699 100644 --- a/fs/ecryptfs/ecryptfs_kernel.h +++ b/fs/ecryptfs/ecryptfs_kernel.h @@ -84,11 +84,16 @@ struct ecryptfs_page_crypt_context { static inline struct ecryptfs_auth_tok * ecryptfs_get_encrypted_key_payload_data(struct key *key) { - if (key->type == &key_type_encrypted) - return (struct ecryptfs_auth_tok *) - (&((struct encrypted_key_payload *)key->payload.data[0])->payload_data); - else + struct encrypted_key_payload *payload; + + if (key->type != &key_type_encrypted) return NULL; + + payload = key->payload.data[0]; + if (!payload) + return ERR_PTR(-EKEYREVOKED); + + return (struct ecryptfs_auth_tok *)payload->payload_data; } static inline struct key *ecryptfs_get_encrypted_key(char *sig) @@ -114,12 +119,17 @@ static inline struct ecryptfs_auth_tok * ecryptfs_get_key_payload_data(struct key *key) { struct ecryptfs_auth_tok *auth_tok; + struct user_key_payload *ukp; auth_tok = ecryptfs_get_encrypted_key_payload_data(key); - if (!auth_tok) - return (struct ecryptfs_auth_tok *)user_key_payload_locked(key)->data; - else + if (auth_tok) return auth_tok; + + ukp = user_key_payload_locked(key); + if (!ukp) + return ERR_PTR(-EKEYREVOKED); + + return (struct ecryptfs_auth_tok *)ukp->data; } #define ECRYPTFS_MAX_KEYSET_SIZE 1024 diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c index 3cf1546dca82..fa218cd64f74 100644 --- a/fs/ecryptfs/keystore.c +++ b/fs/ecryptfs/keystore.c @@ -459,7 +459,8 @@ out: * @auth_tok_key: key containing the authentication token * @auth_tok: authentication token * - * Returns zero on valid auth tok; -EINVAL otherwise + * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or + * -EKEYREVOKED if the key was revoked before we acquired its semaphore. */ static int ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key, @@ -468,6 +469,12 @@ ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key, int rc = 0; (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key); + if (IS_ERR(*auth_tok)) { + rc = PTR_ERR(*auth_tok); + *auth_tok = NULL; + goto out; + } + if (ecryptfs_verify_version((*auth_tok)->version)) { printk(KERN_ERR "Data structure version mismatch. Userspace " "tools must match eCryptfs kernel module with major " From 3cd18d1981731d5f74b8e437009124ac99905d14 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 4 Oct 2017 12:27:00 +0200 Subject: [PATCH 06/15] security/keys: BIG_KEY requires CONFIG_CRYPTO The recent rework introduced a possible randconfig build failure when CONFIG_CRYPTO configured to only allow modules: security/keys/big_key.o: In function `big_key_crypt': big_key.c:(.text+0x29f): undefined reference to `crypto_aead_setkey' security/keys/big_key.o: In function `big_key_init': big_key.c:(.init.text+0x1a): undefined reference to `crypto_alloc_aead' big_key.c:(.init.text+0x45): undefined reference to `crypto_aead_setauthsize' big_key.c:(.init.text+0x77): undefined reference to `crypto_destroy_tfm' crypto/gcm.o: In function `gcm_hash_crypt_remain_continue': gcm.c:(.text+0x167): undefined reference to `crypto_ahash_finup' crypto/gcm.o: In function `crypto_gcm_exit_tfm': gcm.c:(.text+0x847): undefined reference to `crypto_destroy_tfm' When we 'select CRYPTO' like the other users, we always get a configuration that builds. Fixes: 428490e38b2e ("security/keys: rewrite all of big_key crypto") Signed-off-by: Arnd Bergmann Signed-off-by: David Howells --- security/keys/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/security/keys/Kconfig b/security/keys/Kconfig index 91eafada3164..6462e6654ccf 100644 --- a/security/keys/Kconfig +++ b/security/keys/Kconfig @@ -45,6 +45,7 @@ config BIG_KEYS bool "Large payload keys" depends on KEYS depends on TMPFS + select CRYPTO select CRYPTO_AES select CRYPTO_GCM help From 6a6d2a77addce6bc26ccb53df34478b1593f0fbf Mon Sep 17 00:00:00 2001 From: Chun-Yi Lee Date: Wed, 4 Oct 2017 19:18:22 +0800 Subject: [PATCH 07/15] KEYS: Fix the wrong index when checking the existence of second id Fix the wrong index number when checking the existence of second id in function of finding asymmetric key. The id_1 is the second id that the index in array must be 1 but not 0. Fixes: 9eb029893ad5 (KEYS: Generalise x509_request_asymmetric_key()) Cc: David Howells Cc: Herbert Xu Cc: "David S. Miller" Signed-off-by: Chun-Yi Lee Signed-off-by: David Howells --- crypto/asymmetric_keys/asymmetric_type.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c index e4b0ed386bc8..a597f5c5a222 100644 --- a/crypto/asymmetric_keys/asymmetric_type.c +++ b/crypto/asymmetric_keys/asymmetric_type.c @@ -105,7 +105,7 @@ struct key *find_asymmetric_key(struct key *keyring, if (id_0 && id_1) { const struct asymmetric_key_ids *kids = asymmetric_key_ids(key); - if (!kids->id[0]) { + if (!kids->id[1]) { pr_debug("First ID matches, but second is missing\n"); goto reject; } From b3811d36a3e7e7e8ed660bf01151496cf99cf9ed Mon Sep 17 00:00:00 2001 From: Chun-Yi Lee Date: Wed, 4 Oct 2017 16:45:09 +0800 Subject: [PATCH 08/15] KEYS: checking the input id parameters before finding asymmetric key For finding asymmetric key, the input id_0 and id_1 parameters can not be NULL at the same time. This patch adds the BUG_ON checking for id_0 and id_1. Cc: David Howells Cc: Herbert Xu Cc: "David S. Miller" Signed-off-by: Chun-Yi Lee Signed-off-by: David Howells --- crypto/asymmetric_keys/asymmetric_type.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c index a597f5c5a222..39aecad286fe 100644 --- a/crypto/asymmetric_keys/asymmetric_type.c +++ b/crypto/asymmetric_keys/asymmetric_type.c @@ -57,6 +57,8 @@ struct key *find_asymmetric_key(struct key *keyring, char *req, *p; int len; + BUG_ON(!id_0 && !id_1); + if (id_0) { lookup = id_0->data; len = id_0->len; From 363b02dab09b3226f3bd1420dad9c72b79a42a76 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 4 Oct 2017 16:43:25 +0100 Subject: [PATCH 09/15] KEYS: Fix race between updating and finding a negative key Consolidate KEY_FLAG_INSTANTIATED, KEY_FLAG_NEGATIVE and the rejection error into one field such that: (1) The instantiation state can be modified/read atomically. (2) The error can be accessed atomically with the state. (3) The error isn't stored unioned with the payload pointers. This deals with the problem that the state is spread over three different objects (two bits and a separate variable) and reading or updating them atomically isn't practical, given that not only can uninstantiated keys change into instantiated or rejected keys, but rejected keys can also turn into instantiated keys - and someone accessing the key might not be using any locking. The main side effect of this problem is that what was held in the payload may change, depending on the state. For instance, you might observe the key to be in the rejected state. You then read the cached error, but if the key semaphore wasn't locked, the key might've become instantiated between the two reads - and you might now have something in hand that isn't actually an error code. The state is now KEY_IS_UNINSTANTIATED, KEY_IS_POSITIVE or a negative error code if the key is negatively instantiated. The key_is_instantiated() function is replaced with key_is_positive() to avoid confusion as negative keys are also 'instantiated'. Additionally, barriering is included: (1) Order payload-set before state-set during instantiation. (2) Order state-read before payload-read when using the key. Further separate barriering is necessary if RCU is being used to access the payload content after reading the payload pointers. Fixes: 146aa8b1453b ("KEYS: Merge the type-specific data with the payload data") Cc: stable@vger.kernel.org # v4.4+ Reported-by: Eric Biggers Signed-off-by: David Howells Reviewed-by: Eric Biggers --- include/linux/key.h | 47 +++++++++++++++--------- net/dns_resolver/dns_key.c | 2 +- security/keys/big_key.c | 4 +- security/keys/encrypted-keys/encrypted.c | 2 +- security/keys/gc.c | 8 ++-- security/keys/key.c | 31 ++++++++++------ security/keys/keyctl.c | 9 ++--- security/keys/keyring.c | 10 ++--- security/keys/proc.c | 7 +++- security/keys/process_keys.c | 2 +- security/keys/request_key.c | 7 ++-- security/keys/request_key_auth.c | 2 +- security/keys/trusted.c | 2 +- security/keys/user_defined.c | 4 +- 14 files changed, 80 insertions(+), 57 deletions(-) diff --git a/include/linux/key.h b/include/linux/key.h index e315e16b6ff8..8a15cabe928d 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -138,6 +138,11 @@ struct key_restriction { struct key_type *keytype; }; +enum key_state { + KEY_IS_UNINSTANTIATED, + KEY_IS_POSITIVE, /* Positively instantiated */ +}; + /*****************************************************************************/ /* * authentication token / access credential / keyring @@ -169,6 +174,7 @@ struct key { * - may not match RCU dereferenced payload * - payload should contain own length */ + short state; /* Key state (+) or rejection error (-) */ #ifdef KEY_DEBUGGING unsigned magic; @@ -176,18 +182,16 @@ struct key { #endif unsigned long flags; /* status flags (change with bitops) */ -#define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */ -#define KEY_FLAG_DEAD 1 /* set if key type has been deleted */ -#define KEY_FLAG_REVOKED 2 /* set if key had been revoked */ -#define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */ -#define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */ -#define KEY_FLAG_NEGATIVE 5 /* set if key is negative */ -#define KEY_FLAG_ROOT_CAN_CLEAR 6 /* set if key can be cleared by root without permission */ -#define KEY_FLAG_INVALIDATED 7 /* set if key has been invalidated */ -#define KEY_FLAG_BUILTIN 8 /* set if key is built in to the kernel */ -#define KEY_FLAG_ROOT_CAN_INVAL 9 /* set if key can be invalidated by root without permission */ -#define KEY_FLAG_KEEP 10 /* set if key should not be removed */ -#define KEY_FLAG_UID_KEYRING 11 /* set if key is a user or user session keyring */ +#define KEY_FLAG_DEAD 0 /* set if key type has been deleted */ +#define KEY_FLAG_REVOKED 1 /* set if key had been revoked */ +#define KEY_FLAG_IN_QUOTA 2 /* set if key consumes quota */ +#define KEY_FLAG_USER_CONSTRUCT 3 /* set if key is being constructed in userspace */ +#define KEY_FLAG_ROOT_CAN_CLEAR 4 /* set if key can be cleared by root without permission */ +#define KEY_FLAG_INVALIDATED 5 /* set if key has been invalidated */ +#define KEY_FLAG_BUILTIN 6 /* set if key is built in to the kernel */ +#define KEY_FLAG_ROOT_CAN_INVAL 7 /* set if key can be invalidated by root without permission */ +#define KEY_FLAG_KEEP 8 /* set if key should not be removed */ +#define KEY_FLAG_UID_KEYRING 9 /* set if key is a user or user session keyring */ /* the key type and key description string * - the desc is used to match a key against search criteria @@ -213,7 +217,6 @@ struct key { struct list_head name_link; struct assoc_array keys; }; - int reject_error; }; /* This is set on a keyring to restrict the addition of a link to a key @@ -353,17 +356,27 @@ extern void key_set_timeout(struct key *, unsigned); #define KEY_NEED_SETATTR 0x20 /* Require permission to change attributes */ #define KEY_NEED_ALL 0x3f /* All the above permissions */ +static inline short key_read_state(const struct key *key) +{ + /* Barrier versus mark_key_instantiated(). */ + return smp_load_acquire(&key->state); +} + /** - * key_is_instantiated - Determine if a key has been positively instantiated + * key_is_positive - Determine if a key has been positively instantiated * @key: The key to check. * * Return true if the specified key has been positively instantiated, false * otherwise. */ -static inline bool key_is_instantiated(const struct key *key) +static inline bool key_is_positive(const struct key *key) { - return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) && - !test_bit(KEY_FLAG_NEGATIVE, &key->flags); + return key_read_state(key) == KEY_IS_POSITIVE; +} + +static inline bool key_is_negative(const struct key *key) +{ + return key_read_state(key) < 0; } #define dereference_key_rcu(KEY) \ diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c index 8737412c7b27..e1d4d898a007 100644 --- a/net/dns_resolver/dns_key.c +++ b/net/dns_resolver/dns_key.c @@ -224,7 +224,7 @@ static int dns_resolver_match_preparse(struct key_match_data *match_data) static void dns_resolver_describe(const struct key *key, struct seq_file *m) { seq_puts(m, key->description); - if (key_is_instantiated(key)) { + if (key_is_positive(key)) { int err = PTR_ERR(key->payload.data[dns_key_error]); if (err) diff --git a/security/keys/big_key.c b/security/keys/big_key.c index e607830b6154..929e14978c42 100644 --- a/security/keys/big_key.c +++ b/security/keys/big_key.c @@ -247,7 +247,7 @@ void big_key_revoke(struct key *key) /* clear the quota */ key_payload_reserve(key, 0); - if (key_is_instantiated(key) && + if (key_is_positive(key) && (size_t)key->payload.data[big_key_len] > BIG_KEY_FILE_THRESHOLD) vfs_truncate(path, 0); } @@ -279,7 +279,7 @@ void big_key_describe(const struct key *key, struct seq_file *m) seq_puts(m, key->description); - if (key_is_instantiated(key)) + if (key_is_positive(key)) seq_printf(m, ": %zu [%s]", datalen, datalen > BIG_KEY_FILE_THRESHOLD ? "file" : "buff"); diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c index 535db141f4da..d92cbf9687c3 100644 --- a/security/keys/encrypted-keys/encrypted.c +++ b/security/keys/encrypted-keys/encrypted.c @@ -854,7 +854,7 @@ static int encrypted_update(struct key *key, struct key_preparsed_payload *prep) size_t datalen = prep->datalen; int ret = 0; - if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) + if (key_is_negative(key)) return -ENOKEY; if (datalen <= 0 || datalen > 32767 || !prep->data) return -EINVAL; diff --git a/security/keys/gc.c b/security/keys/gc.c index 87cb260e4890..f01d48cb3de1 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -129,15 +129,15 @@ static noinline void key_gc_unused_keys(struct list_head *keys) while (!list_empty(keys)) { struct key *key = list_entry(keys->next, struct key, graveyard_link); + short state = key->state; + list_del(&key->graveyard_link); kdebug("- %u", key->serial); key_check(key); /* Throw away the key data if the key is instantiated */ - if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags) && - !test_bit(KEY_FLAG_NEGATIVE, &key->flags) && - key->type->destroy) + if (state == KEY_IS_POSITIVE && key->type->destroy) key->type->destroy(key); security_key_free(key); @@ -151,7 +151,7 @@ static noinline void key_gc_unused_keys(struct list_head *keys) } atomic_dec(&key->user->nkeys); - if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) + if (state != KEY_IS_UNINSTANTIATED) atomic_dec(&key->user->nikeys); key_user_put(key->user); diff --git a/security/keys/key.c b/security/keys/key.c index eb914a838840..9385e7cc710f 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -401,6 +401,18 @@ int key_payload_reserve(struct key *key, size_t datalen) } EXPORT_SYMBOL(key_payload_reserve); +/* + * Change the key state to being instantiated. + */ +static void mark_key_instantiated(struct key *key, int reject_error) +{ + /* Commit the payload before setting the state; barrier versus + * key_read_state(). + */ + smp_store_release(&key->state, + (reject_error < 0) ? reject_error : KEY_IS_POSITIVE); +} + /* * Instantiate a key and link it into the target keyring atomically. Must be * called with the target keyring's semaphore writelocked. The target key's @@ -424,14 +436,14 @@ static int __key_instantiate_and_link(struct key *key, mutex_lock(&key_construction_mutex); /* can't instantiate twice */ - if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { + if (key->state == KEY_IS_UNINSTANTIATED) { /* instantiate the key */ ret = key->type->instantiate(key, prep); if (ret == 0) { /* mark the key as being instantiated */ atomic_inc(&key->user->nikeys); - set_bit(KEY_FLAG_INSTANTIATED, &key->flags); + mark_key_instantiated(key, 0); if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) awaken = 1; @@ -577,13 +589,10 @@ int key_reject_and_link(struct key *key, mutex_lock(&key_construction_mutex); /* can't instantiate twice */ - if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { + if (key->state == KEY_IS_UNINSTANTIATED) { /* mark the key as being negatively instantiated */ atomic_inc(&key->user->nikeys); - key->reject_error = -error; - smp_wmb(); - set_bit(KEY_FLAG_NEGATIVE, &key->flags); - set_bit(KEY_FLAG_INSTANTIATED, &key->flags); + mark_key_instantiated(key, -error); now = current_kernel_time(); key->expiry = now.tv_sec + timeout; key_schedule_gc(key->expiry + key_gc_delay); @@ -752,8 +761,8 @@ static inline key_ref_t __key_update(key_ref_t key_ref, ret = key->type->update(key, prep); if (ret == 0) - /* updating a negative key instantiates it */ - clear_bit(KEY_FLAG_NEGATIVE, &key->flags); + /* Updating a negative key positively instantiates it */ + mark_key_instantiated(key, 0); up_write(&key->sem); @@ -986,8 +995,8 @@ int key_update(key_ref_t key_ref, const void *payload, size_t plen) ret = key->type->update(key, &prep); if (ret == 0) - /* updating a negative key instantiates it */ - clear_bit(KEY_FLAG_NEGATIVE, &key->flags); + /* Updating a negative key positively instantiates it */ + mark_key_instantiated(key, 0); up_write(&key->sem); diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c index 365ff85d7e27..76d22f726ae4 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -766,10 +766,9 @@ 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; - } + ret = key_read_state(key); + if (ret < 0) + goto error2; /* Negatively instantiated */ /* see if we can read it directly */ ret = key_permission(key_ref, KEY_NEED_READ); @@ -901,7 +900,7 @@ long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group) atomic_dec(&key->user->nkeys); atomic_inc(&newowner->nkeys); - if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { + if (key->state != KEY_IS_UNINSTANTIATED) { atomic_dec(&key->user->nikeys); atomic_inc(&newowner->nikeys); } diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 4fa82a8a9c0e..06173b091a74 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -414,7 +414,7 @@ static void keyring_describe(const struct key *keyring, struct seq_file *m) else seq_puts(m, "[anon]"); - if (key_is_instantiated(keyring)) { + if (key_is_positive(keyring)) { if (keyring->keys.nr_leaves_on_tree != 0) seq_printf(m, ": %lu", keyring->keys.nr_leaves_on_tree); else @@ -553,7 +553,8 @@ static int keyring_search_iterator(const void *object, void *iterator_data) { struct keyring_search_context *ctx = iterator_data; const struct key *key = keyring_ptr_to_key(object); - unsigned long kflags = key->flags; + unsigned long kflags = READ_ONCE(key->flags); + short state = READ_ONCE(key->state); kenter("{%d}", key->serial); @@ -597,9 +598,8 @@ static int keyring_search_iterator(const void *object, void *iterator_data) if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { /* we set a different error code if we pass a negative key */ - if (kflags & (1 << KEY_FLAG_NEGATIVE)) { - smp_rmb(); - ctx->result = ERR_PTR(key->reject_error); + if (state < 0) { + ctx->result = ERR_PTR(state); kleave(" = %d [neg]", ctx->skipped_ret); goto skipped; } diff --git a/security/keys/proc.c b/security/keys/proc.c index de834309d100..4089ce1f7757 100644 --- a/security/keys/proc.c +++ b/security/keys/proc.c @@ -182,6 +182,7 @@ static int proc_keys_show(struct seq_file *m, void *v) unsigned long timo; key_ref_t key_ref, skey_ref; char xbuf[16]; + short state; int rc; struct keyring_search_context ctx = { @@ -236,17 +237,19 @@ static int proc_keys_show(struct seq_file *m, void *v) sprintf(xbuf, "%luw", timo / (60*60*24*7)); } + state = key_read_state(key); + #define showflag(KEY, LETTER, FLAG) \ (test_bit(FLAG, &(KEY)->flags) ? LETTER : '-') seq_printf(m, "%08x %c%c%c%c%c%c%c %5d %4s %08x %5d %5d %-9.9s ", key->serial, - showflag(key, 'I', KEY_FLAG_INSTANTIATED), + state != KEY_IS_UNINSTANTIATED ? 'I' : '-', showflag(key, 'R', KEY_FLAG_REVOKED), showflag(key, 'D', KEY_FLAG_DEAD), showflag(key, 'Q', KEY_FLAG_IN_QUOTA), showflag(key, 'U', KEY_FLAG_USER_CONSTRUCT), - showflag(key, 'N', KEY_FLAG_NEGATIVE), + state < 0 ? 'N' : '-', showflag(key, 'i', KEY_FLAG_INVALIDATED), refcount_read(&key->usage), xbuf, diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c index 293d3598153b..740affd65ee9 100644 --- a/security/keys/process_keys.c +++ b/security/keys/process_keys.c @@ -730,7 +730,7 @@ try_again: ret = -EIO; if (!(lflags & KEY_LOOKUP_PARTIAL) && - !test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) + key_read_state(key) == KEY_IS_UNINSTANTIATED) goto invalid_key; /* check the permissions */ diff --git a/security/keys/request_key.c b/security/keys/request_key.c index 63e63a42db3c..e8036cd0ad54 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -595,10 +595,9 @@ int wait_for_key_construction(struct key *key, bool intr) intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE); if (ret) return -ERESTARTSYS; - if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) { - smp_rmb(); - return key->reject_error; - } + ret = key_read_state(key); + if (ret < 0) + return ret; return key_validate(key); } EXPORT_SYMBOL(wait_for_key_construction); diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c index 6ebf1af8fce9..424e1d90412e 100644 --- a/security/keys/request_key_auth.c +++ b/security/keys/request_key_auth.c @@ -73,7 +73,7 @@ static void request_key_auth_describe(const struct key *key, seq_puts(m, "key:"); seq_puts(m, key->description); - if (key_is_instantiated(key)) + if (key_is_positive(key)) seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len); } diff --git a/security/keys/trusted.c b/security/keys/trusted.c index ddfaebf60fc8..bd85315cbfeb 100644 --- a/security/keys/trusted.c +++ b/security/keys/trusted.c @@ -1066,7 +1066,7 @@ static int trusted_update(struct key *key, struct key_preparsed_payload *prep) char *datablob; int ret = 0; - if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) + if (key_is_negative(key)) return -ENOKEY; p = key->payload.data[0]; if (!p->migratable) diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c index 3d8c68eba516..9f558bedba23 100644 --- a/security/keys/user_defined.c +++ b/security/keys/user_defined.c @@ -114,7 +114,7 @@ int user_update(struct key *key, struct key_preparsed_payload *prep) /* attach the new data, displacing the old */ key->expiry = prep->expiry; - if (!test_bit(KEY_FLAG_NEGATIVE, &key->flags)) + if (key_is_positive(key)) zap = dereference_key_locked(key); rcu_assign_keypointer(key, prep->payload.data[0]); prep->payload.data[0] = NULL; @@ -162,7 +162,7 @@ EXPORT_SYMBOL_GPL(user_destroy); void user_describe(const struct key *key, struct seq_file *m) { seq_puts(m, key->description); - if (key_is_instantiated(key)) + if (key_is_positive(key)) seq_printf(m, ": %u", key->datalen); } From 60ff5b2f547af3828aebafd54daded44cfb0807a Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 12 Oct 2017 16:00:41 +0100 Subject: [PATCH 10/15] KEYS: don't let add_key() update an uninstantiated key Currently, when passed a key that already exists, add_key() will call the key's ->update() method if such exists. But this is heavily broken in the case where the key is uninstantiated because it doesn't call __key_instantiate_and_link(). Consequently, it doesn't do most of the things that are supposed to happen when the key is instantiated, such as setting the instantiation state, clearing KEY_FLAG_USER_CONSTRUCT and awakening tasks waiting on it, and incrementing key->user->nikeys. It also never takes key_construction_mutex, which means that ->instantiate() can run concurrently with ->update() on the same key. In the case of the "user" and "logon" key types this causes a memory leak, at best. Maybe even worse, the ->update() methods of the "encrypted" and "trusted" key types actually just dereference a NULL pointer when passed an uninstantiated key. Change key_create_or_update() to wait interruptibly for the key to finish construction before continuing. This patch only affects *uninstantiated* keys. For now we still allow a negatively instantiated key to be updated (thereby positively instantiating it), although that's broken too (the next patch fixes it) and I'm not sure that anyone actually uses that functionality either. Here is a simple reproducer for the bug using the "encrypted" key type (requires CONFIG_ENCRYPTED_KEYS=y), though as noted above the bug pertained to more than just the "encrypted" key type: #include #include #include int main(void) { int ringid = keyctl_join_session_keyring(NULL); if (fork()) { for (;;) { const char payload[] = "update user:foo 32"; usleep(rand() % 10000); add_key("encrypted", "desc", payload, sizeof(payload), ringid); keyctl_clear(ringid); } } else { for (;;) request_key("encrypted", "desc", "callout_info", ringid); } } It causes: BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 IP: encrypted_update+0xb0/0x170 PGD 7a178067 P4D 7a178067 PUD 77269067 PMD 0 PREEMPT SMP CPU: 0 PID: 340 Comm: reproduce Tainted: G D 4.14.0-rc1-00025-g428490e38b2e #796 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff8a467a39a340 task.stack: ffffb15c40770000 RIP: 0010:encrypted_update+0xb0/0x170 RSP: 0018:ffffb15c40773de8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8a467a275b00 RCX: 0000000000000000 RDX: 0000000000000005 RSI: ffff8a467a275b14 RDI: ffffffffb742f303 RBP: ffffb15c40773e20 R08: 0000000000000000 R09: ffff8a467a275b17 R10: 0000000000000020 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffff8a4677057180 R15: ffff8a467a275b0f FS: 00007f5d7fb08700(0000) GS:ffff8a467f200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000018 CR3: 0000000077262005 CR4: 00000000001606f0 Call Trace: key_create_or_update+0x2bc/0x460 SyS_add_key+0x10c/0x1d0 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x7f5d7f211259 RSP: 002b:00007ffed03904c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000f8 RAX: ffffffffffffffda RBX: 000000003b2a7955 RCX: 00007f5d7f211259 RDX: 00000000004009e4 RSI: 00000000004009ff RDI: 0000000000400a04 RBP: 0000000068db8bad R08: 000000003b2a7955 R09: 0000000000000004 R10: 000000000000001a R11: 0000000000000246 R12: 0000000000400868 R13: 00007ffed03905d0 R14: 0000000000000000 R15: 0000000000000000 Code: 77 28 e8 64 34 1f 00 45 31 c0 31 c9 48 8d 55 c8 48 89 df 48 8d 75 d0 e8 ff f9 ff ff 85 c0 41 89 c4 0f 88 84 00 00 00 4c 8b 7d c8 <49> 8b 75 18 4c 89 ff e8 24 f8 ff ff 85 c0 41 89 c4 78 6d 49 8b RIP: encrypted_update+0xb0/0x170 RSP: ffffb15c40773de8 CR2: 0000000000000018 Cc: # v2.6.12+ Reported-by: Eric Biggers Signed-off-by: David Howells cc: Eric Biggers --- security/keys/key.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/security/keys/key.c b/security/keys/key.c index 9385e7cc710f..83bf4b4afd49 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -945,6 +945,16 @@ error: */ __key_link_end(keyring, &index_key, edit); + key = key_ref_to_ptr(key_ref); + if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) { + ret = wait_for_key_construction(key, true); + if (ret < 0) { + key_ref_put(key_ref); + key_ref = ERR_PTR(ret); + goto error_free_prep; + } + } + key_ref = __key_update(key_ref, &prep); goto error_free_prep; } From 1823d475a5eeaa0f52789b1b7e2d31a592ae92ea Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 27 Sep 2017 12:50:44 -0700 Subject: [PATCH 11/15] KEYS: load key flags and expiry time atomically in key_validate() In key_validate(), load the flags and expiry time once atomically, since these can change concurrently if key_validate() is called without the key semaphore held. And we don't want to get inconsistent results if a variable is referenced multiple times. For example, key->expiry was referenced in both 'if (key->expiry)' and in 'if (now.tv_sec >= key->expiry)', making it theoretically possible to see a spurious EKEYEXPIRED while the expiration time was being removed, i.e. set to 0. Signed-off-by: Eric Biggers Signed-off-by: David Howells --- security/keys/permission.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/security/keys/permission.c b/security/keys/permission.c index 732cc0beffdf..a72b4dd70c8a 100644 --- a/security/keys/permission.c +++ b/security/keys/permission.c @@ -88,7 +88,8 @@ EXPORT_SYMBOL(key_task_permission); */ int key_validate(const struct key *key) { - unsigned long flags = key->flags; + unsigned long flags = READ_ONCE(key->flags); + time_t expiry = READ_ONCE(key->expiry); if (flags & (1 << KEY_FLAG_INVALIDATED)) return -ENOKEY; @@ -99,9 +100,9 @@ int key_validate(const struct key *key) return -EKEYREVOKED; /* check it hasn't expired */ - if (key->expiry) { + if (expiry) { struct timespec now = current_kernel_time(); - if (now.tv_sec >= key->expiry) + if (now.tv_sec >= expiry) return -EKEYEXPIRED; } From 9d6c8711b6a751a694bcfaf49fb557b82092ee46 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 27 Sep 2017 12:50:45 -0700 Subject: [PATCH 12/15] KEYS: Load key expiry time atomically in keyring_search_iterator() Similar to the case for key_validate(), we should load the key ->expiry once atomically in keyring_search_iterator(), since it can be changed concurrently with the flags whenever the key semaphore isn't held. Signed-off-by: Eric Biggers Signed-off-by: David Howells --- security/keys/keyring.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 06173b091a74..a7e51f793867 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -566,6 +566,8 @@ static int keyring_search_iterator(const void *object, void *iterator_data) /* skip invalidated, revoked and expired keys */ if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { + time_t expiry = READ_ONCE(key->expiry); + if (kflags & ((1 << KEY_FLAG_INVALIDATED) | (1 << KEY_FLAG_REVOKED))) { ctx->result = ERR_PTR(-EKEYREVOKED); @@ -573,7 +575,7 @@ static int keyring_search_iterator(const void *object, void *iterator_data) goto skipped; } - if (key->expiry && ctx->now.tv_sec >= key->expiry) { + if (expiry && ctx->now.tv_sec >= expiry) { if (!(ctx->flags & KEYRING_SEARCH_SKIP_EXPIRED)) ctx->result = ERR_PTR(-EKEYEXPIRED); kleave(" = %d [expire]", ctx->skipped_ret); From ab5c69f01313c80df948e4f768efe616258f85f4 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 27 Sep 2017 12:50:46 -0700 Subject: [PATCH 13/15] KEYS: load key flags and expiry time atomically in proc_keys_show() In proc_keys_show(), the key semaphore is not held, so the key ->flags and ->expiry can be changed concurrently. We therefore should read them atomically just once. Signed-off-by: Eric Biggers Signed-off-by: David Howells --- security/keys/proc.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) diff --git a/security/keys/proc.c b/security/keys/proc.c index 4089ce1f7757..6d1fcbba1e09 100644 --- a/security/keys/proc.c +++ b/security/keys/proc.c @@ -179,7 +179,9 @@ static int proc_keys_show(struct seq_file *m, void *v) struct rb_node *_p = v; struct key *key = rb_entry(_p, struct key, serial_node); struct timespec now; + time_t expiry; unsigned long timo; + unsigned long flags; key_ref_t key_ref, skey_ref; char xbuf[16]; short state; @@ -218,12 +220,13 @@ static int proc_keys_show(struct seq_file *m, void *v) rcu_read_lock(); /* come up with a suitable timeout value */ - if (key->expiry == 0) { + expiry = READ_ONCE(key->expiry); + if (expiry == 0) { memcpy(xbuf, "perm", 5); - } else if (now.tv_sec >= key->expiry) { + } else if (now.tv_sec >= expiry) { memcpy(xbuf, "expd", 5); } else { - timo = key->expiry - now.tv_sec; + timo = expiry - now.tv_sec; if (timo < 60) sprintf(xbuf, "%lus", timo); @@ -239,18 +242,19 @@ static int proc_keys_show(struct seq_file *m, void *v) state = key_read_state(key); -#define showflag(KEY, LETTER, FLAG) \ - (test_bit(FLAG, &(KEY)->flags) ? LETTER : '-') +#define showflag(FLAGS, LETTER, FLAG) \ + ((FLAGS & (1 << FLAG)) ? LETTER : '-') + flags = READ_ONCE(key->flags); seq_printf(m, "%08x %c%c%c%c%c%c%c %5d %4s %08x %5d %5d %-9.9s ", key->serial, state != KEY_IS_UNINSTANTIATED ? 'I' : '-', - showflag(key, 'R', KEY_FLAG_REVOKED), - showflag(key, 'D', KEY_FLAG_DEAD), - showflag(key, 'Q', KEY_FLAG_IN_QUOTA), - showflag(key, 'U', KEY_FLAG_USER_CONSTRUCT), + showflag(flags, 'R', KEY_FLAG_REVOKED), + showflag(flags, 'D', KEY_FLAG_DEAD), + showflag(flags, 'Q', KEY_FLAG_IN_QUOTA), + showflag(flags, 'U', KEY_FLAG_USER_CONSTRUCT), state < 0 ? 'N' : '-', - showflag(key, 'i', KEY_FLAG_INVALIDATED), + showflag(flags, 'i', KEY_FLAG_INVALIDATED), refcount_read(&key->usage), xbuf, key->perm, From 68a1fdbbf8bd3378325e45c19e167a165f9ffc3a Mon Sep 17 00:00:00 2001 From: Eric Sesterhenn Date: Sun, 8 Oct 2017 20:02:32 +0200 Subject: [PATCH 14/15] pkcs7: Prevent NULL pointer dereference, since sinfo is not always set. The ASN.1 parser does not necessarily set the sinfo field, this patch prevents a NULL pointer dereference on broken input. Fixes: 99db44350672 ("PKCS#7: Appropriately restrict authenticated attributes and content type") Signed-off-by: Eric Sesterhenn Signed-off-by: David Howells cc: stable@vger.kernel.org # 4.3+ --- crypto/asymmetric_keys/pkcs7_parser.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/crypto/asymmetric_keys/pkcs7_parser.c b/crypto/asymmetric_keys/pkcs7_parser.c index af4cd8649117..d140d8bb2c96 100644 --- a/crypto/asymmetric_keys/pkcs7_parser.c +++ b/crypto/asymmetric_keys/pkcs7_parser.c @@ -88,6 +88,9 @@ static int pkcs7_check_authattrs(struct pkcs7_message *msg) bool want = false; sinfo = msg->signed_infos; + if (!sinfo) + goto inconsistent; + if (sinfo->authattrs) { want = true; msg->have_authattrs = true; From 76ba89c76f2c74e208d93a9e7c698e39eeb3b85c Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Mon, 4 Sep 2017 18:50:05 +0100 Subject: [PATCH 15/15] commoncap: move assignment of fs_ns to avoid null pointer dereference The pointer fs_ns is assigned from inode->i_ib->s_user_ns before a null pointer check on inode, hence if inode is actually null we will get a null pointer dereference on this assignment. Fix this by only dereferencing inode after the null pointer check on inode. Detected by CoverityScan CID#1455328 ("Dereference before null check") Fixes: 8db6c34f1dbc ("Introduce v3 namespaced file capabilities") Signed-off-by: Colin Ian King Cc: stable@vger.kernel.org Acked-by: Serge Hallyn Signed-off-by: James Morris --- security/commoncap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/security/commoncap.c b/security/commoncap.c index c25e0d27537f..fc46f5b85251 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -585,13 +585,14 @@ int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data struct vfs_ns_cap_data data, *nscaps = &data; struct vfs_cap_data *caps = (struct vfs_cap_data *) &data; kuid_t rootkuid; - struct user_namespace *fs_ns = inode->i_sb->s_user_ns; + struct user_namespace *fs_ns; memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data)); if (!inode) return -ENODATA; + fs_ns = inode->i_sb->s_user_ns; size = __vfs_getxattr((struct dentry *)dentry, inode, XATTR_NAME_CAPS, &data, XATTR_CAPS_SZ); if (size == -ENODATA || size == -EOPNOTSUPP)