| From bippy-1.1.0 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-2022-49837: bpf: Fix memory leaks in __check_func_call |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| bpf: Fix memory leaks in __check_func_call |
| |
| kmemleak reports this issue: |
| |
| unreferenced object 0xffff88817139d000 (size 2048): |
| comm "test_progs", pid 33246, jiffies 4307381979 (age 45851.820s) |
| hex dump (first 32 bytes): |
| 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ |
| 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ |
| backtrace: |
| [<0000000045f075f0>] kmalloc_trace+0x27/0xa0 |
| [<0000000098b7c90a>] __check_func_call+0x316/0x1230 |
| [<00000000b4c3c403>] check_helper_call+0x172e/0x4700 |
| [<00000000aa3875b7>] do_check+0x21d8/0x45e0 |
| [<000000001147357b>] do_check_common+0x767/0xaf0 |
| [<00000000b5a595b4>] bpf_check+0x43e3/0x5bc0 |
| [<0000000011e391b1>] bpf_prog_load+0xf26/0x1940 |
| [<0000000007f765c0>] __sys_bpf+0xd2c/0x3650 |
| [<00000000839815d6>] __x64_sys_bpf+0x75/0xc0 |
| [<00000000946ee250>] do_syscall_64+0x3b/0x90 |
| [<0000000000506b7f>] entry_SYSCALL_64_after_hwframe+0x63/0xcd |
| |
| The root case here is: In function prepare_func_exit(), the callee is |
| not released in the abnormal scenario after "state->curframe--;". To |
| fix, move "state->curframe--;" to the very bottom of the function, |
| right when we free callee and reset frame[] pointer to NULL, as Andrii |
| suggested. |
| |
| In addition, function __check_func_call() has a similar problem. In |
| the abnormal scenario before "state->curframe++;", the callee also |
| should be released by free_func_state(). |
| |
| The Linux kernel CVE team has assigned CVE-2022-49837 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.20 with commit fd978bf7fd312581a7ca454a991f0ffb34c4204b and fixed in 5.15.80 with commit d4944497827a3d14bc5a26dbcfb7433eb5a956c0 |
| Issue introduced in 4.20 with commit fd978bf7fd312581a7ca454a991f0ffb34c4204b and fixed in 6.0.10 with commit 83946d772e756734a900ef99dbe0aeda506adf37 |
| Issue introduced in 4.20 with commit fd978bf7fd312581a7ca454a991f0ffb34c4204b and fixed in 6.1 with commit eb86559a691cea5fa63e57a03ec3dc9c31e97955 |
| |
| 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-2022-49837 |
| 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: |
| kernel/bpf/verifier.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/d4944497827a3d14bc5a26dbcfb7433eb5a956c0 |
| https://git.kernel.org/stable/c/83946d772e756734a900ef99dbe0aeda506adf37 |
| https://git.kernel.org/stable/c/eb86559a691cea5fa63e57a03ec3dc9c31e97955 |
