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Fri, 28 Aug 2026 01:49:15 -0700 (PDT) From: Coiby Xu To: kexec@lists.infradead.org Cc: Andrew Morton , Sourabh Jain , Baoquan He , Dave Young , Pratyush Yadav , Mike Rapoport , Pasha Tatashin , linux-kernel@vger.kernel.org (open list) Subject: [PATCH v4 3/9] crash_dump: Read the number of dm-crypt keys from reserved memory Date: Fri, 28 Aug 2026 16:48:49 +0800 Message-ID: <20260828084900.1496839-4-coiby.xu@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260828084900.1496839-1-coiby.xu@gmail.com> References: <20260828084900.1496839-1-coiby.xu@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 026c7de4ad85..0b9e09c60745 100644 --- a/kernel/crash_dump_dm_crypt.c +++ b/kernel/crash_dump_dm_crypt.c @@ -89,21 +89,31 @@ 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; + } + + 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) @@ -447,12 +457,12 @@ int crash_load_dm_crypt_keys(struct kimage *image) mutex_lock(&config_keys_subsys.su_mutex); mutex_acquired = true; - 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; @@ -463,7 +473,7 @@ 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; -- 2.55.0