Add helper functions for manipulating the transaction stack, and
for validating the transaction stack during binder transactions
and replies.
Signed-off-by: Riley Andrews <riandrews@xxxxxxxxxxx>
---
drivers/android/binder.c | 126 +++++++++++++++++++++++++++++------------------
1 file changed, 79 insertions(+), 47 deletions(-)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 99a3270..ed94121 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -1167,14 +1167,20 @@ static int binder_dec_ref(struct binder_ref *ref, int strong)
return 0;
}
+static void binder_push_transaction(struct binder_thread *thread,
+ struct binder_transaction *t)
+{
+ t->from_parent = thread->transaction_stack;
+ thread->transaction_stack = t;
+}
+
static void binder_pop_transaction(struct binder_thread *target_thread,
struct binder_transaction *t)
{
if (target_thread) {
BUG_ON(target_thread->transaction_stack != t);
BUG_ON(target_thread->transaction_stack->from != target_thread);
- target_thread->transaction_stack =
- target_thread->transaction_stack->from_parent;
+ target_thread->transaction_stack = t->from_parent;
t->from = NULL;
}
t->need_reply = 0;
@@ -1184,6 +1190,24 @@ static void binder_pop_transaction(struct binder_thread *target_thread,
binder_stats_deleted(BINDER_STAT_TRANSACTION);
}
+static void binder_dst_save_transaction(struct binder_thread *thread,
+ struct binder_transaction *t)
+{
+ t->to_parent = thread->transaction_stack;
+ thread->transaction_stack = t;
+}
+
+static struct binder_transaction *
+binder_dst_restore_transaction(struct binder_thread *thread)
+{
+ struct binder_transaction *t = thread->transaction_stack;
+
+ if (!t)
+ return NULL;
+ thread->transaction_stack = t->to_parent;
+ return t;
+}
+
static void binder_send_failed_reply(struct binder_transaction *t,
uint32_t error_code)
{
@@ -1559,6 +1583,47 @@ static int binder_get_tr_target_node(struct binder_thread *thread,
return BR_OK;
}
+static int binder_reply_validate_stack(struct binder_thread *thread)
+{
+ struct binder_proc *proc = thread->proc;
+ struct binder_transaction *in_reply_to = NULL;
+
+ in_reply_to = thread->transaction_stack;
+ if (!in_reply_to) {
+ binder_user_error("%d:%d got reply transaction with no transaction stack\n",
+ proc->pid, thread->pid);
+ return BR_FAILED_REPLY;
+ }
+ if (in_reply_to->to_thread != thread) {
+ binder_user_error("%d:%d got reply transaction with bad transaction stack, transaction %d has target %d:%d\n",
+ proc->pid, thread->pid, in_reply_to->debug_id,
+ in_reply_to->to_proc ?
+ in_reply_to->to_proc->pid : 0,
+ in_reply_to->to_thread ?
+ in_reply_to->to_thread->pid : 0);
+ return BR_FAILED_REPLY;
+ }
+ return BR_OK;
+}
+
+static int binder_tr_validate_stack(struct binder_thread *thread)
+{
+ struct binder_transaction *prior = thread->transaction_stack;
+ struct binder_proc *proc = thread->proc;
+
+ if (prior->to_thread != thread) {
+ binder_user_error("%d:%d got new transaction with bad transaction stack, transaction %d has target %d:%d\n",
+ proc->pid, thread->pid,
+ prior->debug_id,
+ prior->to_proc ?
+ prior->to_proc->pid : 0,
+ prior->to_thread ?
+ prior->to_thread->pid : 0);
+ return BR_FAILED_REPLY;
+ }
+ return BR_OK;
+}
+
static void binder_transaction(struct binder_thread *thread,
struct binder_transaction_data *tr, int reply)
{
@@ -1584,42 +1649,17 @@ static void binder_transaction(struct binder_thread *thread,
e->offsets_size = tr->offsets_size;
if (reply) {
- in_reply_to = thread->transaction_stack;
- if (in_reply_to == NULL) {
- binder_user_error("%d:%d got reply transaction with no transaction stack\n",
- proc->pid, thread->pid);
- return_error = BR_FAILED_REPLY;
- goto err_empty_call_stack;
- }
- binder_set_nice(in_reply_to->saved_priority);
- if (in_reply_to->to_thread != thread) {
- binder_user_error("%d:%d got reply transaction with bad transaction stack, transaction %d has target %d:%d\n",
- proc->pid, thread->pid, in_reply_to->debug_id,
- in_reply_to->to_proc ?
- in_reply_to->to_proc->pid : 0,
- in_reply_to->to_thread ?
- in_reply_to->to_thread->pid : 0);
- return_error = BR_FAILED_REPLY;
- in_reply_to = NULL;
+ return_error = binder_reply_validate_stack(thread);
+ if (return_error != BR_OK)
goto err_bad_call_stack;
- }
- thread->transaction_stack = in_reply_to->to_parent;
+ in_reply_to = binder_dst_restore_transaction(thread);
+ binder_set_nice(in_reply_to->saved_priority);
target_thread = in_reply_to->from;
- if (target_thread == NULL) {
+ if (!target_thread) {
return_error = BR_DEAD_REPLY;
goto err_dead_binder;
}
- if (target_thread->transaction_stack != in_reply_to) {
- binder_user_error("%d:%d got reply transaction with bad target transaction stack %d, expected %d\n",
- proc->pid, thread->pid,
- target_thread->transaction_stack ?
- target_thread->transaction_stack->debug_id : 0,
- in_reply_to->debug_id);
- return_error = BR_FAILED_REPLY;
- in_reply_to = NULL;
- target_thread = NULL;
- goto err_dead_binder;
- }
+ BUG_ON(target_thread->transaction_stack != in_reply_to);
target_proc = target_thread->proc;
} else {
return_error = binder_get_tr_target_node(thread, tr,
@@ -1640,16 +1680,11 @@ static void binder_transaction(struct binder_thread *thread,
if (!(tr->flags & TF_ONE_WAY) && thread->transaction_stack) {
struct binder_transaction *tmp;
- tmp = thread->transaction_stack;
- if (tmp->to_thread != thread) {
- binder_user_error("%d:%d got new transaction with bad transaction stack, transaction %d has target %d:%d\n",
- proc->pid, thread->pid, tmp->debug_id,
- tmp->to_proc ? tmp->to_proc->pid : 0,
- tmp->to_thread ?
- tmp->to_thread->pid : 0);
- return_error = BR_FAILED_REPLY;
+ return_error = binder_tr_validate_stack(thread);
+ if (return_error != BR_OK)
goto err_bad_call_stack;
- }
+
+ tmp = thread->transaction_stack;
while (tmp) {
if (tmp->from && tmp->from->proc == target_proc)
target_thread = tmp->from;
@@ -1755,8 +1790,7 @@ static void binder_transaction(struct binder_thread *thread,
} else if (!(t->flags & TF_ONE_WAY)) {
BUG_ON(t->buffer->async_transaction != 0);
t->need_reply = 1;
- t->from_parent = thread->transaction_stack;
- thread->transaction_stack = t;
+ binder_push_transaction(thread, t);
} else {
BUG_ON(target_node == NULL);
BUG_ON(t->buffer->async_transaction != 1);
@@ -1786,7 +1820,6 @@ err_alloc_tcomplete_failed:
binder_stats_deleted(BINDER_STAT_TRANSACTION);
err_alloc_t_failed:
err_bad_call_stack:
-err_empty_call_stack:
err_dead_binder:
err_invalid_target_handle:
binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
@@ -2579,9 +2612,8 @@ retry:
list_del(&t->work.entry);
t->buffer->allow_user_free = 1;
if (cmd == BR_TRANSACTION && !(t->flags & TF_ONE_WAY)) {
- t->to_parent = thread->transaction_stack;
t->to_thread = thread;
- thread->transaction_stack = t;
+ binder_dst_save_transaction(thread, t);
} else {
t->buffer->transaction = NULL;
kfree(t);
--
2.2.0.rc0.207.ga3a616c
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