CVE-2022-49080 Information

Mar 01, 2025 cve

Description

In the Linux kernel the following vulnerability has been resolved:

mm/mempolicy: fix mpol_new leak in shared_policy_replace

If mpol_new is allocated but not used in restart loop mpol_new will be freed via mpol_put before returning to the caller. But refcnt is not initialized yet so mpol_put could not do the right things and might leak the unused mpol_new. This would happen if mempolicy was updated on the shared shmem file while the sp->lock has been dropped during the memory allocation.

This issue could be triggered easily with the below code snippet if there are many processes doing the below work at the same time:

shmid = shmget((key_t)5566 1024 PAGE_SIZE 0666|IPC_CREAT); shm = shmat(shmid 0 0); loop many times mbind(shm 1024 PAGE_SIZE MPOL_LOCAL mask maxnode 0); mbind(shm + 128 PAGE_SIZE 128 PAGE_SIZE MPOL_DEFAULT mask maxnode 0);

Reference

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