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staging: vchiq: Fix list_for_each exit tests 

After a list_for_each_entry() loop, the list iterator is always non-NULL
so these conditions don't work.  If the "waiter" is not found then this
results in an out of bounds access.

I have fixed it by introducing a new "found" variable.  In one case, I
used an else statement for readability.

Fixes: 46e4b9ec4f ("staging: vchiq_arm: use list_for_each_entry when accessing bulk_waiter_list")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20201006134748.GA2076872@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Dan Carpenter 2020-10-06 16:47:48 +03:00 committed by Greg Kroah-Hartman
parent 6c75a92a00
commit 8750de90ac
1 changed files with 7 additions and 5 deletions
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12
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
View File

@ -432,6 +432,7 @@ vchiq_blocking_bulk_transfer(unsigned int handle, void *data,
struct vchiq_service *service;
enum vchiq_status status;
struct bulk_waiter_node *waiter = NULL;
bool found = false;
service = find_service_by_handle(handle);
if (!service)
@ -445,12 +446,13 @@ vchiq_blocking_bulk_transfer(unsigned int handle, void *data,
list_for_each_entry(waiter, &instance->bulk_waiter_list, list) {
if (waiter->pid == current->pid) {
list_del(&waiter->list);
found = true;
break;
}
}
mutex_unlock(&instance->bulk_waiter_list_mutex);
if (waiter) {
if (found) {
struct vchiq_bulk *bulk = waiter->bulk_waiter.bulk;
if (bulk) {
@ -467,9 +469,7 @@ vchiq_blocking_bulk_transfer(unsigned int handle, void *data,
spin_unlock(&bulk_waiter_spinlock);
}
}
}
if (!waiter) {
} else {
waiter = kzalloc(sizeof(struct bulk_waiter_node), GFP_KERNEL);
if (!waiter) {
vchiq_log_error(vchiq_core_log_level,
@ -952,6 +952,7 @@ static int vchiq_irq_queue_bulk_tx_rx(struct vchiq_instance *instance,
{
struct vchiq_service *service;
struct bulk_waiter_node *waiter = NULL;
bool found = false;
void *userdata = NULL;
int status = 0;
int ret;
@ -975,11 +976,12 @@ static int vchiq_irq_queue_bulk_tx_rx(struct vchiq_instance *instance,
list) {
if (waiter->pid == current->pid) {
list_del(&waiter->list);
found = true;
break;
}
}
mutex_unlock(&instance->bulk_waiter_list_mutex);
if (!waiter) {
if (!found) {
vchiq_log_error(vchiq_arm_log_level,
"no bulk_waiter found for pid %d",
current->pid);