UBUNTU-CVE-2021-3491
The io_uring subsystem in the Linux kernel allowed the MAX_RW_COUNT limit to be bypassed in the PROVIDE_BUFFERS operation, which led to negative values being usedin mem_rw when reading /proc/<PID>/mem. This could be used to create a heap overflow leading to arbitrary code execution in the kernel. It was addressed via commit d1f82808877b ("io_uring: truncate lengths larger than MAX_RW_COUNT on provide buffers") (v5.13-rc1) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced in ddf0322db79c ("io_uring: add IORING_OP_PROVIDE_BUFFERS") (v5.7-rc1).
02 / AFFECTED SOFTWARE
Affected packages
23 explicit affected versions
6 explicit affected versions
10 explicit affected versions
44 explicit affected versions
16 explicit affected versions
4 explicit affected versions
38 explicit affected versions
13 explicit affected versions
12 explicit affected versions
43 explicit affected versions
10 explicit affected versions
7 explicit affected versions
9 explicit affected versions
17 explicit affected versions
11 explicit affected versions
6 explicit affected versions
7 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
The io_uring subsystem in the Linux kernel allowed the MAX_RW_COUNT limit to be bypassed in the PROVIDE_BUFFERS operation, which led to negative values being usedin mem_rw when reading /proc/<PID>/mem. This could be used to create a heap overflow leading to arbitrary code execution in the kernel. It was addressed via commit d1f82808877b ("io_uring: truncate lengths larger than MAX_RW_COUNT on provide buffers") (v5.13-rc1) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced in ddf0322db79c ("io_uring: add IORING_OP_PROVIDE_BUFFERS") (v5.7-rc1).
05 / REFERENCES
Further evidence
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d1f82808877bb10d3deee7cf3374a4eb3fb582db
- https://ubuntu.com/security/CVE-2021-3491
- https://ubuntu.com/security/notices/USN-4948-1
- https://ubuntu.com/security/notices/USN-4949-1
- https://ubuntu.com/security/notices/USN-4950-1
- https://www.cve.org/CVERecord?id=CVE-2021-3491
- https://www.openwall.com/lists/oss-security/2021/05/11/13