| Message ID | 0f9bbbc4800d5329485b6bdabbbe1ef3b2169b02.1637862358.git.msuchanek@suse.de (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | KEXEC_SIG with appended signature | expand |
Hi Michal, On Thu, 25 Nov 2021 19:02:42 +0100 Michal Suchanek <msuchanek@suse.de> wrote: > It is stripped by each caller separately. > > Signed-off-by: Michal Suchanek <msuchanek@suse.de> > --- > 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; >
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;
It is stripped by each caller separately. Signed-off-by: Michal Suchanek <msuchanek@suse.de> --- arch/powerpc/kexec/elf_64.c | 9 --------- arch/s390/kernel/machine_kexec_file.c | 9 --------- kernel/module.c | 7 +------ kernel/module_signing.c | 12 ++++++++++-- 4 files changed, 11 insertions(+), 26 deletions(-)