From bippy-c9c4e1df01b2 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman To: Reply-to: , Subject: CVE-2024-36016: tty: n_gsm: fix possible out-of-bounds in gsm0_receive() Description =========== In the Linux kernel, the following vulnerability has been resolved: tty: n_gsm: fix possible out-of-bounds in gsm0_receive() Assuming the following: - side A configures the n_gsm in basic option mode - side B sends the header of a basic option mode frame with data length 1 - side A switches to advanced option mode - side B sends 2 data bytes which exceeds gsm->len Reason: gsm->len is not used in advanced option mode. - side A switches to basic option mode - side B keeps sending until gsm0_receive() writes past gsm->buf Reason: Neither gsm->state nor gsm->len have been reset after reconfiguration. Fix this by changing gsm->count to gsm->len comparison from equal to less than. Also add upper limit checks against the constant MAX_MRU in gsm0_receive() and gsm1_receive() to harden against memory corruption of gsm->len and gsm->mru. All other checks remain as we still need to limit the data according to the user configuration and actual payload size. The Linux kernel CVE team has assigned CVE-2024-36016 to this issue. Affected and fixed versions =========================== Issue introduced in 2.6.35 with commit e1eaea46bb40 and fixed in 4.19.316 with commit 9513d4148950 Issue introduced in 2.6.35 with commit e1eaea46bb40 and fixed in 5.4.278 with commit b229bc6c6ea9 Issue introduced in 2.6.35 with commit e1eaea46bb40 and fixed in 5.10.219 with commit 0fb736c9931e Issue introduced in 2.6.35 with commit e1eaea46bb40 and fixed in 5.15.161 with commit 4c267110fc11 Issue introduced in 2.6.35 with commit e1eaea46bb40 and fixed in 6.1.93 with commit 46f52c89a7e7 Issue introduced in 2.6.35 with commit e1eaea46bb40 and fixed in 6.6.33 with commit 774d83b008ec Issue introduced in 2.6.35 with commit e1eaea46bb40 and fixed in 6.8.12 with commit f126ce7305fe Issue introduced in 2.6.35 with commit e1eaea46bb40 and fixed in 6.9.3 with commit b890d45aaf02 Issue introduced in 2.6.35 with commit e1eaea46bb40 and fixed in 6.10 with commit 47388e807f85 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2024-36016 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: drivers/tty/n_gsm.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/9513d4148950b05bc99fa7314dc883cc0e1605e5 https://git.kernel.org/stable/c/b229bc6c6ea9fe459fc3fa94fd0a27a2f32aca56 https://git.kernel.org/stable/c/0fb736c9931e02dbc7d9a75044c8e1c039e50f04 https://git.kernel.org/stable/c/4c267110fc110390704cc065edb9817fdd10ff54 https://git.kernel.org/stable/c/46f52c89a7e7d2691b97a9728e4591d071ca8abc https://git.kernel.org/stable/c/774d83b008eccb1c48c14dc5486e7aa255731350 https://git.kernel.org/stable/c/f126ce7305fe88f49cdabc6db4168b9318898ea3 https://git.kernel.org/stable/c/b890d45aaf02b564e6cae2d2a590f9649330857d https://git.kernel.org/stable/c/47388e807f85948eefc403a8a5fdc5b406a65d5a