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Wed, 6 May 2026 14:18:01 +0000 (GMT) Message-ID: <0e2328f1-a057-45d5-8889-c5c333826b45@linux.ibm.com> Date: Wed, 6 May 2026 19:48:00 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 4/9] crash_dump: Read the number of dm-crypt keys from reserved memory To: Coiby Xu , kexec@lists.infradead.org Cc: Andrew Morton , Baoquan He , Dave Young , Mike Rapoport , Pasha Tatashin , Pratyush Yadav , Coiby Xu , open list References: <20260501234342.2518281-1-coiby.xu@gmail.com> <20260501234342.2518281-5-coiby.xu@gmail.com> Content-Language: en-US From: Sourabh Jain In-Reply-To: <20260501234342.2518281-5-coiby.xu@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNTA2MDEzOSBTYWx0ZWRfX9y0MwTyLjfiV xNyIF4eTe4WHuiJxc60K608meVTSm6aKPwh8mvxeRc9pP9lwGzDTDnL1EObM8kJSkKb+xCU0itY QXAy8Slzjo9+gsAgzFg7F3CHNsmAAQhwJaeh7nssiBUdjd32rPkP+p4OhJ2hUaHqm1t+GR5LldV EP2hYyqQUiO5d8sd5eXqCRLWnQCm0Er0khwJR3P8P9NroKKq/72cPUPWJig1xqaKxVC083UnAct /f/jQoiHcvExbFGv6PXv316JynRySCbSw0LDEgb4sD1T69oL8XA6kR0wnsQmcTgR7XrABN4+/t6 9nDaYfSBoEwxIMCMmMU0fU4ggpePwYsWzYbpgKlNgOFYgX49NJ7k9HTbA0FvFkgnMQDHOeIW74s Z8s/frQLHMNzt2JLpxDKM3DHj/ORycx3t+d40GIf8YqgzmuxFD2NACdWdthBDUn5z0+3fIFbjfa uVmsRoFPGdJuQEVoeuA== X-Proofpoint-ORIG-GUID: jBeBQxKUNSjzFUkYS9XDntMgoZ2jlYD- X-Proofpoint-GUID: Gh7Gu9yIkmJfJgfDLU3OiIIsCkREUkv4 X-Authority-Analysis: v=2.4 cv=W7UIkxWk c=1 sm=1 tr=0 ts=69fb4da0 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=IkcTkHD0fZMA:10 a=NGcC8JguVDcA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=VnNF1IyMAAAA:8 a=pGLkceISAAAA:8 a=4dglYSz4F3maezcncv4A:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-05-05_03,2026-05-06_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 adultscore=0 lowpriorityscore=0 malwarescore=0 suspectscore=0 spamscore=0 clxscore=1015 phishscore=0 bulkscore=0 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2604200000 definitions=main-2605060139 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260506_071831_252330_F0C4CB5E X-CRM114-Status: GOOD ( 21.71 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On 02/05/26 05:13, Coiby Xu wrote: > In case user adds/deletes the keys by mistake, it's safer to read the > number of keys from reserved memory. > > Fixes: 9ebfa8dcaea7 ("crash_dump: reuse saved dm crypt keys for CPU/memory hot-plugging") > Reported-and-Suggested-by: Sourabh Jain > Signed-off-by: Coiby Xu > --- > kernel/crash_dump_dm_crypt.c | 36 +++++++++++++++++++++++------------- > 1 file changed, 23 insertions(+), 13 deletions(-) > > diff --git a/kernel/crash_dump_dm_crypt.c b/kernel/crash_dump_dm_crypt.c > index 6377ee86ec50..a3e460714d23 100644 > --- a/kernel/crash_dump_dm_crypt.c > +++ b/kernel/crash_dump_dm_crypt.c > @@ -88,21 +88,31 @@ static int get_keys_from_kdump_reserved_memory(void) > { > struct keys_header *keys_header_loaded; > size_t keys_header_size; > - > - keys_header_size = get_keys_header_size(key_count); > - keys_header = kzalloc(keys_header_size, GFP_KERNEL); > - if (!keys_header) > - return -ENOMEM; > + int r = 0; > > arch_kexec_unprotect_crashkres(); > keys_header_loaded = kmap_local_page(pfn_to_page( > kexec_crash_image->dm_crypt_keys_addr >> PAGE_SHIFT)); > > + if (keys_header_loaded->total_keys <= 0 || > + keys_header_loaded->total_keys > KEY_NUM_MAX) { > + pr_warn("keys_header saved to reserved memory may be corrupt\n"); > + r = -EINVAL; > + goto kunmap; > + } Yes it is good to do a sanity check before using it. - Sourabh Jain > + > + keys_header_size = get_keys_header_size(keys_header_loaded->total_keys); > + keys_header = kzalloc(keys_header_size, GFP_KERNEL); > + if (!keys_header) { > + r = -ENOMEM; > + goto kunmap; > + } > + > memcpy(keys_header, keys_header_loaded, keys_header_size); > +kunmap: > kunmap_local(keys_header_loaded); > arch_kexec_protect_crashkres(); > - > - return 0; > + return r; > } > > static int restore_dm_crypt_keys_to_thread_keyring(void) > @@ -431,12 +441,12 @@ int crash_load_dm_crypt_keys(struct kimage *image) > > mutex_lock(&config_keys_subsys.su_mutex); > > - if (key_count <= 0) { > - kexec_dprintk("No dm-crypt keys\n"); > - return 0; > - } > - > if (!is_dm_key_reused) { > + if (key_count <= 0) { > + kexec_dprintk("No dm-crypt keys\n"); > + return 0; > + } > + > r = build_keys_header(); > if (r) > goto out; > @@ -447,7 +457,7 @@ int crash_load_dm_crypt_keys(struct kimage *image) > * cleaned up at the end of kexec_file_load syscall > */ > kbuf.buffer = keys_header; > - kbuf.bufsz = get_keys_header_size(key_count); > + kbuf.bufsz = get_keys_header_size(keys_header->total_keys); > > kbuf.memsz = kbuf.bufsz; > kbuf.buf_align = ELF_CORE_HEADER_ALIGN;