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authorLinus Torvalds <torvalds@linux-foundation.org>2017-10-15 07:50:38 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2017-10-15 07:50:38 -0400
commitae7df8f985f1b0445366ae6f6324cd08a218526e (patch)
tree7531517ec51cab79594fea13157f9a1a77d67d57 /drivers/android
parent7a263b16c5a258b2f3fe5b58a7c461cc9d34e99a (diff)
parent512cf465ee01eb23936a9e6ed0b6414eccb00853 (diff)
Merge tag 'char-misc-4.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc driver fixes from Greg KH: "Here are 4 patches to resolve some char/misc driver issues found these past weeks. One of them is a mei bugfix and another is a new mei device id. There is also a hyper-v fix for a reported issue, and a binder issue fix for a problem reported by a few people. All of these have been in my tree for a while, I don't know if linux-next is really testing much this month. But 0-day is happy with them :)" * tag 'char-misc-4.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: binder: fix use-after-free in binder_transaction() Drivers: hv: vmbus: Fix bugs in rescind handling mei: me: add gemini lake devices id mei: always use domain runtime pm callbacks.
Diffstat (limited to 'drivers/android')
-rw-r--r--drivers/android/binder.c93
1 files changed, 66 insertions, 27 deletions
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index ab34239a76ee..0621a95b8597 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2582,6 +2582,48 @@ static bool binder_proc_transaction(struct binder_transaction *t,
return true;
}
+/**
+ * binder_get_node_refs_for_txn() - Get required refs on node for txn
+ * @node: struct binder_node for which to get refs
+ * @proc: returns @node->proc if valid
+ * @error: if no @proc then returns BR_DEAD_REPLY
+ *
+ * User-space normally keeps the node alive when creating a transaction
+ * since it has a reference to the target. The local strong ref keeps it
+ * alive if the sending process dies before the target process processes
+ * the transaction. If the source process is malicious or has a reference
+ * counting bug, relying on the local strong ref can fail.
+ *
+ * Since user-space can cause the local strong ref to go away, we also take
+ * a tmpref on the node to ensure it survives while we are constructing
+ * the transaction. We also need a tmpref on the proc while we are
+ * constructing the transaction, so we take that here as well.
+ *
+ * Return: The target_node with refs taken or NULL if no @node->proc is NULL.
+ * Also sets @proc if valid. If the @node->proc is NULL indicating that the
+ * target proc has died, @error is set to BR_DEAD_REPLY
+ */
+static struct binder_node *binder_get_node_refs_for_txn(
+ struct binder_node *node,
+ struct binder_proc **procp,
+ uint32_t *error)
+{
+ struct binder_node *target_node = NULL;
+
+ binder_node_inner_lock(node);
+ if (node->proc) {
+ target_node = node;
+ binder_inc_node_nilocked(node, 1, 0, NULL);
+ binder_inc_node_tmpref_ilocked(node);
+ node->proc->tmp_ref++;
+ *procp = node->proc;
+ } else
+ *error = BR_DEAD_REPLY;
+ binder_node_inner_unlock(node);
+
+ return target_node;
+}
+
static void binder_transaction(struct binder_proc *proc,
struct binder_thread *thread,
struct binder_transaction_data *tr, int reply,
@@ -2685,43 +2727,35 @@ static void binder_transaction(struct binder_proc *proc,
ref = binder_get_ref_olocked(proc, tr->target.handle,
true);
if (ref) {
- binder_inc_node(ref->node, 1, 0, NULL);
- target_node = ref->node;
- }
- binder_proc_unlock(proc);
- if (target_node == NULL) {
+ target_node = binder_get_node_refs_for_txn(
+ ref->node, &target_proc,
+ &return_error);
+ } else {
binder_user_error("%d:%d got transaction to invalid handle\n",
- proc->pid, thread->pid);
+ proc->pid, thread->pid);
return_error = BR_FAILED_REPLY;
- return_error_param = -EINVAL;
- return_error_line = __LINE__;
- goto err_invalid_target_handle;
}
+ binder_proc_unlock(proc);
} else {
mutex_lock(&context->context_mgr_node_lock);
target_node = context->binder_context_mgr_node;
- if (target_node == NULL) {
+ if (target_node)
+ target_node = binder_get_node_refs_for_txn(
+ target_node, &target_proc,
+ &return_error);
+ else
return_error = BR_DEAD_REPLY;
- mutex_unlock(&context->context_mgr_node_lock);
- return_error_line = __LINE__;
- goto err_no_context_mgr_node;
- }
- binder_inc_node(target_node, 1, 0, NULL);
mutex_unlock(&context->context_mgr_node_lock);
}
- e->to_node = target_node->debug_id;
- binder_node_lock(target_node);
- target_proc = target_node->proc;
- if (target_proc == NULL) {
- binder_node_unlock(target_node);
- return_error = BR_DEAD_REPLY;
+ if (!target_node) {
+ /*
+ * return_error is set above
+ */
+ return_error_param = -EINVAL;
return_error_line = __LINE__;
goto err_dead_binder;
}
- binder_inner_proc_lock(target_proc);
- target_proc->tmp_ref++;
- binder_inner_proc_unlock(target_proc);
- binder_node_unlock(target_node);
+ e->to_node = target_node->debug_id;
if (security_binder_transaction(proc->tsk,
target_proc->tsk) < 0) {
return_error = BR_FAILED_REPLY;
@@ -3071,6 +3105,8 @@ static void binder_transaction(struct binder_proc *proc,
if (target_thread)
binder_thread_dec_tmpref(target_thread);
binder_proc_dec_tmpref(target_proc);
+ if (target_node)
+ binder_dec_node_tmpref(target_node);
/*
* write barrier to synchronize with initialization
* of log entry
@@ -3090,6 +3126,8 @@ err_bad_parent:
err_copy_data_failed:
trace_binder_transaction_failed_buffer_release(t->buffer);
binder_transaction_buffer_release(target_proc, t->buffer, offp);
+ if (target_node)
+ binder_dec_node_tmpref(target_node);
target_node = NULL;
t->buffer->transaction = NULL;
binder_alloc_free_buf(&target_proc->alloc, t->buffer);
@@ -3104,13 +3142,14 @@ err_bad_call_stack:
err_empty_call_stack:
err_dead_binder:
err_invalid_target_handle:
-err_no_context_mgr_node:
if (target_thread)
binder_thread_dec_tmpref(target_thread);
if (target_proc)
binder_proc_dec_tmpref(target_proc);
- if (target_node)
+ if (target_node) {
binder_dec_node(target_node, 1, 0);
+ binder_dec_node_tmpref(target_node);
+ }
binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
"%d:%d transaction failed %d/%d, size %lld-%lld line %d\n",

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