| From bippy-1.2.0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@kernel.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2025-37893: LoongArch: BPF: Fix off-by-one error in build_prologue() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| LoongArch: BPF: Fix off-by-one error in build_prologue() |
| |
| Vincent reported that running BPF progs with tailcalls on LoongArch |
| causes kernel hard lockup. Debugging the issues shows that the JITed |
| image missing a jirl instruction at the end of the epilogue. |
| |
| There are two passes in JIT compiling, the first pass set the flags and |
| the second pass generates JIT code based on those flags. With BPF progs |
| mixing bpf2bpf and tailcalls, build_prologue() generates N insns in the |
| first pass and then generates N+1 insns in the second pass. This makes |
| epilogue_offset off by one and we will jump to some unexpected insn and |
| cause lockup. Fix this by inserting a nop insn. |
| |
| The Linux kernel CVE team has assigned CVE-2025-37893 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.1 with commit 5dc615520c4dfb358245680f1904bad61116648e and fixed in 6.6.87 with commit b3ffad2f02db4aace6799fe0049508b8925eae45 |
| Issue introduced in 6.1 with commit 5dc615520c4dfb358245680f1904bad61116648e and fixed in 6.12.23 with commit 205a2182c51ffebaef54d643e3745e720cded08b |
| Issue introduced in 6.1 with commit 5dc615520c4dfb358245680f1904bad61116648e and fixed in 6.13.11 with commit c74d95a5679741ef428974ab788f5b0758dc78ae |
| Issue introduced in 6.1 with commit 5dc615520c4dfb358245680f1904bad61116648e and fixed in 6.14.2 with commit 48b904de2408af5f936f0e03f48dfcddeab58aa0 |
| Issue introduced in 6.1 with commit 5dc615520c4dfb358245680f1904bad61116648e and fixed in 6.15 with commit 7e2586991e36663c9bc48c828b83eab180ad30a9 |
| |
| 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-2025-37893 |
| 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: |
| arch/loongarch/net/bpf_jit.c |
| arch/loongarch/net/bpf_jit.h |
| |
| |
| 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/b3ffad2f02db4aace6799fe0049508b8925eae45 |
| https://git.kernel.org/stable/c/205a2182c51ffebaef54d643e3745e720cded08b |
| https://git.kernel.org/stable/c/c74d95a5679741ef428974ab788f5b0758dc78ae |
| https://git.kernel.org/stable/c/48b904de2408af5f936f0e03f48dfcddeab58aa0 |
| https://git.kernel.org/stable/c/7e2586991e36663c9bc48c828b83eab180ad30a9 |
