md/raid1: Fix stack memory use after return in raid1_reshape

Vulnerability Description

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.

References

• https://git.kernel.org/stable/c/d8a6853d00fbaa810765c8ed2f452a5832273968
• https://git.kernel.org/stable/c/12b00ec99624f8da8c325f2dd6e807df26df0025
• https://git.kernel.org/stable/c/48da050b4f54ed639b66278d0ae6f4107b2c4e2d
• https://git.kernel.org/stable/c/5f35e48b76655e45522df338876dfef88dafcc71
• https://git.kernel.org/stable/c/df5894014a92ff0196dbc212a7764e97366fd2b7
• https://git.kernel.org/stable/c/776e6186dc9ecbdb8a1b706e989166c8a99bbf64
• https://git.kernel.org/stable/c/61fd5e93006cf82ec8ee5c115ab5cf4bbd104bdb
• https://git.kernel.org/stable/c/d67ed2ccd2d1dcfda9292c0ea8697a9d0f2f0d98