CVE-2021-29155
An issue was discovered in the Linux kernel through 5.11.x. kernel/bpf/verifier.c performs undesirable out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory. Specifically, for sequences of pointer arithmetic operations, the pointer modification performed by the first operation is not correctly accounted for when restricting subsequent operations.
02 / AFFECTED SOFTWARE
Affected packages
1 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
An issue was discovered in the Linux kernel through 5.11.x. kernel/bpf/verifier.c performs undesirable out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory. Specifically, for sequences of pointer arithmetic operations, the pointer modification performed by the first operation is not correctly accounted for when restricting subsequent operations.
In several functions of verifier.c, there is a possible way to disclose kernel memory due to side channel information disclosure. This could lead to local information disclosure with System execution privileges needed. User interaction is not needed for exploitation.
05 / REFERENCES
Further evidence
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=073815b756c51ba9d8384d924c5d1c03ca3d1ae4
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=24c109bb1537c12c02aeed2d51a347b4d6a9b76e
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6f55b2f2a1178856c19bbce2f71449926e731914
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=7fedb63a8307dda0ec3b8969a3b233a1dd7ea8e0
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=9601148392520e2e134936e76788fc2a6371e7be
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=a6aaece00a57fa6f22575364b3903dfbccf5345d
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b658bbb844e28f1862867f37e8ca11a8e2aa94a3
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=f528819334881fd622fdadeddb3f7edaed8b7c9b
- https://lists.debian.org/debian-lts-announce/2021/06/msg00019.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CUX2CA63453G34C6KYVBLJXJXEARZI2X/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PAEQ3H6HKNO6KUCGRZVYSFSAGEUX23JL/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XZASHZVCOFJ4VU2I3BN5W5EPHWJQ7QWX/
- https://www.kernel.org
- https://www.openwall.com/lists/oss-security/2021/04/18/4
- https://android.googlesource.com/kernel/common/+/073815b756c51ba9d8384d924c5d1c03ca3d1ae4
- https://android.googlesource.com/kernel/common/+/24c109bb1537c12c02aeed2d51a347b4d6a9b76e
- https://android.googlesource.com/kernel/common/+/6f55b2f2a1178856c19bbce2f71449926e731914
- https://android.googlesource.com/kernel/common/+/7fedb63a8307dda0ec3b8969a3b233a1dd7ea8e0
- https://android.googlesource.com/kernel/common/+/9601148392520e2e134936e76788fc2a6371e7be
- https://android.googlesource.com/kernel/common/+/a6aaece00a57fa6f22575364b3903dfbccf5345d
- https://android.googlesource.com/kernel/common/+/b658bbb844e28f1862867f37e8ca11a8e2aa94a3
- https://android.googlesource.com/kernel/common/+/f528819334881fd622fdadeddb3f7edaed8b7c9b
- https://source.android.com/security/bulletin/2021-10-01