| 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-2021-47428: powerpc/64s: fix program check interrupt emergency stack path |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| powerpc/64s: fix program check interrupt emergency stack path |
| |
| Emergency stack path was jumping into a 3: label inside the |
| __GEN_COMMON_BODY macro for the normal path after it had finished, |
| rather than jumping over it. By a small miracle this is the correct |
| place to build up a new interrupt frame with the existing stack |
| pointer, so things basically worked okay with an added weird looking |
| 700 trap frame on top (which had the wrong ->nip so it didn't decode |
| bug messages either). |
| |
| Fix this by avoiding using numeric labels when jumping over non-trivial |
| macros. |
| |
| Before: |
| |
| LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV |
| Modules linked in: |
| CPU: 0 PID: 88 Comm: sh Not tainted 5.15.0-rc2-00034-ge057cdade6e5 #2637 |
| NIP: 7265677368657265 LR: c00000000006c0c8 CTR: c0000000000097f0 |
| REGS: c0000000fffb3a50 TRAP: 0700 Not tainted |
| MSR: 9000000000021031 <SF,HV,ME,IR,DR,LE> CR: 00000700 XER: 20040000 |
| CFAR: c0000000000098b0 IRQMASK: 0 |
| GPR00: c00000000006c964 c0000000fffb3cf0 c000000001513800 0000000000000000 |
| GPR04: 0000000048ab0778 0000000042000000 0000000000000000 0000000000001299 |
| GPR08: 000001e447c718ec 0000000022424282 0000000000002710 c00000000006bee8 |
| GPR12: 9000000000009033 c0000000016b0000 00000000000000b0 0000000000000001 |
| GPR16: 0000000000000000 0000000000000002 0000000000000000 0000000000000ff8 |
| GPR20: 0000000000001fff 0000000000000007 0000000000000080 00007fff89d90158 |
| GPR24: 0000000002000000 0000000002000000 0000000000000255 0000000000000300 |
| GPR28: c000000001270000 0000000042000000 0000000048ab0778 c000000080647e80 |
| NIP [7265677368657265] 0x7265677368657265 |
| LR [c00000000006c0c8] ___do_page_fault+0x3f8/0xb10 |
| Call Trace: |
| [c0000000fffb3cf0] [c00000000000bdac] soft_nmi_common+0x13c/0x1d0 (unreliable) |
| --- interrupt: 700 at decrementer_common_virt+0xb8/0x230 |
| NIP: c0000000000098b8 LR: c00000000006c0c8 CTR: c0000000000097f0 |
| REGS: c0000000fffb3d60 TRAP: 0700 Not tainted |
| MSR: 9000000000021031 <SF,HV,ME,IR,DR,LE> CR: 22424282 XER: 20040000 |
| CFAR: c0000000000098b0 IRQMASK: 0 |
| GPR00: c00000000006c964 0000000000002400 c000000001513800 0000000000000000 |
| GPR04: 0000000048ab0778 0000000042000000 0000000000000000 0000000000001299 |
| GPR08: 000001e447c718ec 0000000022424282 0000000000002710 c00000000006bee8 |
| GPR12: 9000000000009033 c0000000016b0000 00000000000000b0 0000000000000001 |
| GPR16: 0000000000000000 0000000000000002 0000000000000000 0000000000000ff8 |
| GPR20: 0000000000001fff 0000000000000007 0000000000000080 00007fff89d90158 |
| GPR24: 0000000002000000 0000000002000000 0000000000000255 0000000000000300 |
| GPR28: c000000001270000 0000000042000000 0000000048ab0778 c000000080647e80 |
| NIP [c0000000000098b8] decrementer_common_virt+0xb8/0x230 |
| LR [c00000000006c0c8] ___do_page_fault+0x3f8/0xb10 |
| --- interrupt: 700 |
| Instruction dump: |
| XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX |
| XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX |
| ---[ end trace 6d28218e0cc3c949 ]--- |
| |
| After: |
| |
| ------------[ cut here ]------------ |
| kernel BUG at arch/powerpc/kernel/exceptions-64s.S:491! |
| Oops: Exception in kernel mode, sig: 5 [#1] |
| LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV |
| Modules linked in: |
| CPU: 0 PID: 88 Comm: login Not tainted 5.15.0-rc2-00034-ge057cdade6e5-dirty #2638 |
| NIP: c0000000000098b8 LR: c00000000006bf04 CTR: c0000000000097f0 |
| REGS: c0000000fffb3d60 TRAP: 0700 Not tainted |
| MSR: 9000000000021031 <SF,HV,ME,IR,DR,LE> CR: 24482227 XER: 00040000 |
| CFAR: c0000000000098b0 IRQMASK: 0 |
| GPR00: c00000000006bf04 0000000000002400 c000000001513800 c000000001271868 |
| GPR04: 00000000100f0d29 0000000042000000 0000000000000007 0000000000000009 |
| GPR08: 00000000100f0d29 0000000024482227 0000000000002710 c000000000181b3c |
| GPR12: 9000000000009033 c0000000016b0000 00000000100f0d29 c000000005b22f00 |
| GPR16: 00000000ffff0000 0000000000000001 0000000000000009 00000000100eed90 |
| GPR20: 00000000100eed90 0000000010000000 000000001000a49c 00000000100f1430 |
| GPR24: c000000001271868 0000000002000000 0000000000000215 0000000000000300 |
| GPR28: c000000001271800 0000000042000000 00000000100f0d29 c000000080647860 |
| NIP [c0000000000098b8] decrementer_common_virt+0xb8/0x230 |
| LR [c00000000006bf04] ___do_page_fault+0x234/0xb10 |
| Call Trace: |
| Instruction dump: |
| 4182000c 39400001 48000008 894d0932 714a0001 39400008 408225fc 718a4000 |
| 7c2a0b78 3821fcf0 41c20008 e82d0910 <0981fcf0> f92101a0 f9610170 f9810178 |
| ---[ end trace a5dbd1f5ea4ccc51 ]--- |
| |
| The Linux kernel CVE team has assigned CVE-2021-47428 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.3 with commit 0a882e28468f48ab3d9a36dde0a5723ea29ed1ed and fixed in 5.10.73 with commit 411b38fe68ba20a8bbe724b0939762c3f16e16ca |
| Issue introduced in 5.3 with commit 0a882e28468f48ab3d9a36dde0a5723ea29ed1ed and fixed in 5.14.12 with commit c835b3d1d6362b4a4ebb192da7e7fd27a0a45d01 |
| Issue introduced in 5.3 with commit 0a882e28468f48ab3d9a36dde0a5723ea29ed1ed and fixed in 5.15 with commit 3e607dc4df180b72a38e75030cb0f94d12808712 |
| |
| 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-2021-47428 |
| 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/powerpc/kernel/exceptions-64s.S |
| |
| |
| 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/411b38fe68ba20a8bbe724b0939762c3f16e16ca |
| https://git.kernel.org/stable/c/c835b3d1d6362b4a4ebb192da7e7fd27a0a45d01 |
| https://git.kernel.org/stable/c/3e607dc4df180b72a38e75030cb0f94d12808712 |
