| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2023-52767: tls: fix NULL deref on tls_sw_splice_eof() with empty record |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| tls: fix NULL deref on tls_sw_splice_eof() with empty record |
| |
| syzkaller discovered that if tls_sw_splice_eof() is executed as part of |
| sendfile() when the plaintext/ciphertext sk_msg are empty, the send path |
| gets confused because the empty ciphertext buffer does not have enough |
| space for the encryption overhead. This causes tls_push_record() to go on |
| the `split = true` path (which is only supposed to be used when interacting |
| with an attached BPF program), and then get further confused and hit the |
| tls_merge_open_record() path, which then assumes that there must be at |
| least one populated buffer element, leading to a NULL deref. |
| |
| It is possible to have empty plaintext/ciphertext buffers if we previously |
| bailed from tls_sw_sendmsg_locked() via the tls_trim_both_msgs() path. |
| tls_sw_push_pending_record() already handles this case correctly; let's do |
| the same check in tls_sw_splice_eof(). |
| |
| The Linux kernel CVE team has assigned CVE-2023-52767 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.5 with commit df720d288dbb1793e82b6ccbfc670ec871e9def4 and fixed in 6.6.4 with commit 2214e2bb5489145aba944874d0ee1652a0a63dc8 |
| Issue introduced in 6.5 with commit df720d288dbb1793e82b6ccbfc670ec871e9def4 and fixed in 6.7 with commit 53f2cb491b500897a619ff6abd72f565933760f0 |
| |
| 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-2023-52767 |
| 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: |
| net/tls/tls_sw.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/944900fe2736c07288efe2d9394db4d3ca23f2c9 |
| https://git.kernel.org/stable/c/2214e2bb5489145aba944874d0ee1652a0a63dc8 |
| https://git.kernel.org/stable/c/53f2cb491b500897a619ff6abd72f565933760f0 |
