Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
md/raid1: Fix stack memory use after return in raid1_reshape
In the raid1_reshape function, newpool is allocated on the stack and assigned to conf->r1bio_pool. This results in conf->r1bio_pool.wait.head pointing to a stack address. Accessing this address later can lead to a kernel panic.
Example access path:
raid1_reshape() { // newpool is on the stack mempool_t newpool, oldpool; // initialize newpool.wait.head to stack address mempool_init(&newpool, …); conf->r1bio_pool = newpool; }
raid1_read_request() or raid1_write_request() { alloc_r1bio() { mempool_alloc() { // if pool->alloc fails remove_element() { –pool->curr_nr; } } } }
mempool_free() { if (pool->curr_nr < pool->min_nr) { // pool->wait.head is a stack address // wake_up() will try to access this invalid address // which leads to a kernel panic return; wake_up(&pool->wait); } }
Fix: reinit conf->r1bio_pool.wait after assigning newpool.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , Oracle Linux 7 ELS , TuxCare 9.6 ESU , Ubuntu 20.04 ELS
- Affected packages:
- linux @ 5.4.0 (+7 more)
In the Linux kernel, the following vulnerability has been resolved:
md/raid1: Fix stack memory use after return in raid1_reshape
In the raid1_reshape function, newpool is allocated on the stack and assigned to conf->r1bio_pool. This results in conf->r1bio_pool.wait.head pointing to a stack address. Accessing this address later can lead to a kernel panic.
Example access path:
raid1_reshape() { // newpool is on the stack mempool_t newpool, oldpool; // initialize newpool.wait.head to stack address mempool_init(&newpool, …); conf->r1bio_pool = newpool; }
raid1_read_request() or raid1_write_request() { alloc_r1bio() { mempool_alloc() { // if pool->alloc fails remove_element() { –pool->curr_nr; } } } }
mempool_free() { if (pool->curr_nr < pool->min_nr) { // pool->wait.head is a stack address // wake_up() will try to access this invalid address // which leads to a kernel panic return; wake_up(&pool->wait); } }
Fix: reinit conf->r1bio_pool.wait after assigning newpool.