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Mon, 31 Aug 2026 06:40:04 -0700 (PDT) From: Coiby Xu X-Google-Original-From: Coiby Xu Date: Mon, 31 Aug 2026 21:36:33 +0800 To: Jinjie Ruan Cc: Sourabh Jain , catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, chenhuacai@kernel.org, kernel@xen0n.name, maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, chleroy@kernel.org, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, akpm@linux-foundation.org, baoquan.he@linux.dev, rppt@kernel.org, pasha.tatashin@soleen.com, pratyush@kernel.org, ruirui.yang@linux.dev, kees@kernel.org, thuth@redhat.com, gshan@redhat.com, jic23@kernel.org, james.morse@arm.com, ardb@kernel.org, leitao@debian.org, yeoreum.yun@arm.com, tangyouling@kylinos.cn, hbathini@linux.ibm.com, adityag@linux.ibm.com, ionut.nechita@windriver.com, liaoyuanhong@vivo.com, seanjc@google.com, fuqiang.wang@easystack.cn, makb@juniper.net, piliu@redhat.com, ebiggers@kernel.org, jbouron@amazon.com, mclapinski@google.com, me@linux.beauty, graf@amazon.com, bgwin@google.com, robh@kernel.org, takahiro.akashi@linaro.org, palmer@rivosinc.com, x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v3 07/17] crash_dump: Fix potential double-free of keys_header Message-ID: References: <20260826092541.3905933-1-ruanjinjie@huawei.com> <20260826092541.3905933-8-ruanjinjie@huawei.com> <87186b8a-f68c-400b-97cf-8ea6129eba69@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Mon, Aug 31, 2026 at 09:24:07AM +0800, Jinjie Ruan wrote: > > >在 2026/8/30 13:59, Sourabh Jain 写道: >> Hello Jinjie, >> >> Coiby is handling this issue in the below patch series: >> https://lore.kernel.org/all/20260828084900.1496839-2-coiby.xu@gmail.com/ >> >> Since the above patch series is all about crash_load_dm_crypt_keys, >> could you >> please consider dropping this patch from your series and reviewing his >> patch >> instead? > >Absolutely, happy to do so — I'll drop this patch and review Coiby's >series instead. Hi Jinjie, Thank you for agreeing to drop your patch and review mine instead! > >> >> Thanks, >> Sourabh Jain >> >> On 26/08/26 14:55, Jinjie Ruan wrote: >>> `keys_header` was freed in `build_keys_header()` without being reset >>> to NULL, and the error path in `crash_load_dm_crypt_keys()` freed it >>> unconditionally even when reused, leading to double-free or >>> use-after-free. >>> >>> Add `free_keys_header()` to centralize freeing and NULL-setting. >>> Use it in `build_keys_header()` and only free in the error path when >>> the header was newly built (`!is_dm_key_reused`). >>> >>> Cc: Andrew Morton >>> Cc: Baoquan He >>> Cc: Mike Rapoport >>> Cc: Pasha Tatashin >>> Cc: Pratyush Yadav >>> Cc: Dave Young >>> Cc: stable@vger.kernel.org >>> Fixes: e3a84be1ec2f ("arm64,ppc64le/kdump: pass dm-crypt keys to kdump >>> kernel") >>> Signed-off-by: Jinjie Ruan >>> --- >>>   kernel/crash_dump_dm_crypt.c | 15 +++++++++++---- >>>   1 file changed, 11 insertions(+), 4 deletions(-) >>> >>> diff --git a/kernel/crash_dump_dm_crypt.c b/kernel/crash_dump_dm_crypt.c >>> index c685497cd470..ed0960ff0987 100644 >>> --- a/kernel/crash_dump_dm_crypt.c >>> +++ b/kernel/crash_dump_dm_crypt.c >>> @@ -363,15 +363,21 @@ static struct configfs_subsystem >>> config_keys_subsys = { >>>       }, >>>   }; >>>   +static void free_keys_header(void) >>> +{ >>> +    if (keys_header) { >>> +        kvfree(keys_header); >>> +        keys_header = NULL; >>> +    } >>> +} >>> + >>>   static int build_keys_header(void) >>>   { >>>       struct config_item *item = NULL; >>>       struct config_key *key; >>>       int i, r; >>>   -    if (keys_header != NULL) >>> -        kvfree(keys_header); >>> - >>> +    free_keys_header(); >>>       keys_header = kzalloc(get_keys_header_size(key_count), GFP_KERNEL); >>>       if (!keys_header) >>>           return -ENOMEM; >>> @@ -441,7 +447,8 @@ int crash_load_dm_crypt_keys(struct kimage *image) >>>       r = kexec_add_buffer(&kbuf); >>>       if (r) { >>>           pr_err("Failed to call kexec_add_buffer, ret=%d\n", r); >>> -        kvfree((void *)kbuf.buffer); >>> +        if (!is_dm_key_reused) >>> +            free_keys_header(); >>>           return r; >>>       } >>>       image->dm_crypt_keys_addr = kbuf.mem; >> > -- Best regards, Coiby