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[219.76.18.204]) by smtp.gmail.com with ESMTPSA id 00721157ae682-81e6c201dc7sm39007147b3.41.2026.07.10.01.00.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 10 Jul 2026 01:00:02 -0700 (PDT) From: Coiby Xu X-Google-Original-From: Coiby Xu Date: Fri, 10 Jul 2026 15:59:19 +0800 To: Sourabh Jain Cc: kexec@lists.infradead.org, Andrew Morton , Baoquan He , Dave Young , Mike Rapoport , Pasha Tatashin , Pratyush Yadav , Coiby Xu , open list Subject: Re: [PATCH v2 4/9] crash_dump: Read the number of dm-crypt keys from reserved memory Message-ID: References: <20260501234342.2518281-1-coiby.xu@gmail.com> <20260501234342.2518281-5-coiby.xu@gmail.com> <0e2328f1-a057-45d5-8889-c5c333826b45@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <0e2328f1-a057-45d5-8889-c5c333826b45@linux.ibm.com> On Wed, May 06, 2026 at 07:48:00PM +0530, Sourabh Jain wrote: > > >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 Thanks! Yeah, better safe than sorry! -- Best regards, Coiby