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Message-ID: <20211207171112.03850036@rhtmp> In-Reply-To: <0f9bbbc4800d5329485b6bdabbbe1ef3b2169b02.1637862358.git.msuchanek@suse.de> References: <0f9bbbc4800d5329485b6bdabbbe1ef3b2169b02.1637862358.git.msuchanek@suse.de> Organization: Red Hat inc. MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nayna , Mimi Zohar , David Howells , keyrings@vger.kernel.org, Paul Mackerras , Alexander Gordeev , Rob Herring , Herbert Xu , Baoquan He , Christian Borntraeger , James Morris , Lakshmi Ramasubramanian , Christian Borntraeger , "Serge E. Hallyn" , Vasily Gorbik , linux-s390@vger.kernel.org, Heiko Carstens , linux-crypto@vger.kernel.org, Hari Bathini , Daniel Axtens , Dmitry Kasatkin , Frank van der Linden , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Luis Chamberlain , Sven Schnelle , linux-security-module@vger.kernel.org, Jessica Yu , linux-integrity@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, "David S. Miller" , Thiago Jung Bauermann , buendgen@de.ibm.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hi Michal, On Thu, 25 Nov 2021 19:02:42 +0100 Michal Suchanek wrote: > It is stripped by each caller separately. > > Signed-off-by: Michal Suchanek > --- > arch/powerpc/kexec/elf_64.c | 9 --------- > arch/s390/kernel/machine_kexec_file.c | 9 --------- > kernel/module.c | 7 +------ > kernel/module_signing.c | 12 ++++++++++-- kernel/module_signing.c is only compiled with MODULE_SIG enabled but KEXEC_SIG only selects MODULE_SIG_FORMAT. In the unlikely case that KEXEC_SIG is enabled but MODULE_SIG isn't this causes a build breakage. So you need to update KEXEC_SIG to select MODULE_SIG instead of MODULE_SIG_FORMAT for s390 and ppc. Thanks Philipp > 4 files changed, 11 insertions(+), 26 deletions(-) > > diff --git a/arch/powerpc/kexec/elf_64.c b/arch/powerpc/kexec/elf_64.c > index 266cb26d3ca0..63634c95265d 100644 > --- a/arch/powerpc/kexec/elf_64.c > +++ b/arch/powerpc/kexec/elf_64.c > @@ -156,15 +156,6 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, > int elf64_verify_sig(const char *kernel, unsigned long length) > { > size_t kernel_len = length; > - const unsigned long marker_len = sizeof(MODULE_SIG_STRING) - 1; > - > - if (marker_len > kernel_len) > - return -EKEYREJECTED; > - > - if (memcmp(kernel + kernel_len - marker_len, MODULE_SIG_STRING, > - marker_len)) > - return -EKEYREJECTED; > - kernel_len -= marker_len; > > return verify_appended_signature(kernel, &kernel_len, VERIFY_USE_PLATFORM_KEYRING, > "kexec_file"); > diff --git a/arch/s390/kernel/machine_kexec_file.c b/arch/s390/kernel/machine_kexec_file.c > index 432797249db3..c4632c1a1b59 100644 > --- a/arch/s390/kernel/machine_kexec_file.c > +++ b/arch/s390/kernel/machine_kexec_file.c > @@ -27,20 +27,11 @@ const struct kexec_file_ops * const kexec_file_loaders[] = { > int s390_verify_sig(const char *kernel, unsigned long length) > { > size_t kernel_len = length; > - const unsigned long marker_len = sizeof(MODULE_SIG_STRING) - 1; > > /* Skip signature verification when not secure IPLed. */ > if (!ipl_secure_flag) > return 0; > > - if (marker_len > kernel_len) > - return -EKEYREJECTED; > - > - if (memcmp(kernel + kernel_len - marker_len, MODULE_SIG_STRING, > - marker_len)) > - return -EKEYREJECTED; > - kernel_len -= marker_len; > - > return verify_appended_signature(kernel, &kernel_len, VERIFY_USE_PLATFORM_KEYRING, > "kexec_file"); > } > diff --git a/kernel/module.c b/kernel/module.c > index 8481933dfa92..d91ca0f93a40 100644 > --- a/kernel/module.c > +++ b/kernel/module.c > @@ -2882,7 +2882,6 @@ static inline void kmemleak_load_module(const struct module *mod, > static int module_sig_check(struct load_info *info, int flags) > { > int err = -ENODATA; > - const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1; > const char *reason; > const void *mod = info->hdr; > > @@ -2890,11 +2889,7 @@ static int module_sig_check(struct load_info *info, int flags) > * Require flags == 0, as a module with version information > * removed is no longer the module that was signed > */ > - if (flags == 0 && > - info->len > markerlen && > - memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) { > - /* We truncate the module to discard the signature */ > - info->len -= markerlen; > + if (flags == 0) { > err = verify_appended_signature(mod, &info->len, > VERIFY_USE_SECONDARY_KEYRING, "module"); > if (!err) { > diff --git a/kernel/module_signing.c b/kernel/module_signing.c > index f492e410564d..4c28cb55275f 100644 > --- a/kernel/module_signing.c > +++ b/kernel/module_signing.c > @@ -15,8 +15,7 @@ > #include "module-internal.h" > > /** > - * verify_appended_signature - Verify the signature on a module with the > - * signature marker stripped. > + * verify_appended_signature - Verify the signature on a module > * @data: The data to be verified > * @len: Size of @data. > * @trusted_keys: Keyring to use for verification > @@ -25,12 +24,21 @@ > int verify_appended_signature(const void *data, size_t *len, > struct key *trusted_keys, const char *what) > { > + const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1; > struct module_signature ms; > size_t sig_len, modlen = *len; > int ret; > > pr_devel("==>%s(,%zu)\n", __func__, modlen); > > + if (markerlen > modlen) > + return -ENODATA; > + > + if (memcmp(data + modlen - markerlen, MODULE_SIG_STRING, > + markerlen)) > + return -ENODATA; > + modlen -= markerlen; > + > if (modlen <= sizeof(ms)) > return -EBADMSG; >