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| author | Elena Reshetova <elena.reshetova@intel.com> | 2017-03-31 15:20:49 +0300 |
|---|---|---|
| committer | James Morris <james.l.morris@oracle.com> | 2017-04-03 10:49:06 +1000 |
| commit | ddb99e118e37f324a4be65a411bb60ae62795cf9 (patch) | |
| tree | 9fecb40084bb937fafa04eaf57d9bc4ae3bcb6a9 | |
| parent | fff292914d3a2f1efd05ca71c2ba72a3c663201e (diff) | |
| download | op-kernel-dev-ddb99e118e37f324a4be65a411bb60ae62795cf9.zip op-kernel-dev-ddb99e118e37f324a4be65a411bb60ae62795cf9.tar.gz | |
security, keys: convert key_user.usage from atomic_t to refcount_t
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
| -rw-r--r-- | security/keys/internal.h | 3 | ||||
| -rw-r--r-- | security/keys/key.c | 6 | ||||
| -rw-r--r-- | security/keys/proc.c | 2 | ||||
| -rw-r--r-- | security/keys/process_keys.c | 2 |
4 files changed, 7 insertions, 6 deletions
diff --git a/security/keys/internal.h b/security/keys/internal.h index a2f4c0a..6bee06a 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -17,6 +17,7 @@ #include <linux/key-type.h> #include <linux/task_work.h> #include <linux/keyctl.h> +#include <linux/refcount.h> struct iovec; @@ -53,7 +54,7 @@ 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; diff --git a/security/keys/key.c b/security/keys/key.c index ff92443..b4958b3 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); diff --git a/security/keys/proc.c b/security/keys/proc.c index 69199f1..bf08d02 100644 --- a/security/keys/proc.c +++ b/security/keys/proc.c @@ -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 b6fdd22..44451af 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), |
