From: Michal Suchanek <msuchanek@suse.de>
To: keyrings@vger.kernel.org
Cc: Nayna <nayna@linux.vnet.ibm.com>,
Mimi Zohar <zohar@linux.ibm.com>,
David Howells <dhowells@redhat.com>,
Paul Mackerras <paulus@samba.org>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Rob Herring <robh@kernel.org>,
Herbert Xu <herbert@gondor.apana.org.au>,
Baoquan He <bhe@redhat.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
James Morris <jmorris@namei.org>,
Lakshmi Ramasubramanian <nramas@linux.microsoft.com>,
Michal Suchanek <msuchanek@suse.de>,
"Serge E. Hallyn" <serge@hallyn.com>,
Vasily Gorbik <gor@linux.ibm.com>,
linux-s390@vger.kernel.org, Heiko Carstens <hca@linux.ibm.com>,
linux-crypto@vger.kernel.org,
Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
Hari Bathini <hbathini@linux.ibm.com>,
Daniel Axtens <dja@axtens.net>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Philipp Rudo <prudo@redhat.com>,
Frank van der Linden <fllinden@amazon.com>,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
Luis Chamberlain <mcgrof@kernel.org>,
Sven Schnelle <svens@linux.ibm.com>,
linux-security-module@vger.kernel.org,
Jessica Yu <jeyu@kernel.org>,
linux-integrity@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
"David S. Miller" <davem@davemloft.net>,
Thiago Jung Bauermann <bauerman@linux.ibm.com>,
buendgen@de.ibm.com
Subject: [PATCH v2 4/6] module: strip the signature marker in the verification function.
Date: Thu, 25 Nov 2021 19:02:42 +0100 [thread overview]
Message-ID: <0f9bbbc4800d5329485b6bdabbbe1ef3b2169b02.1637862358.git.msuchanek@suse.de> (raw)
In-Reply-To: <cover.1637862358.git.msuchanek@suse.de>
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(-)
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;
--
2.31.1
next prev parent reply other threads:[~2021-11-25 18:06 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-25 18:02 [PATCH v2 0/6] KEXEC_SIG with appended signature Michal Suchanek
2021-11-25 18:02 ` [PATCH v2 1/6] s390/kexec_file: Don't opencode appended signature check Michal Suchanek
2021-11-25 18:02 ` [PATCH v2 2/6] powerpc/kexec_file: Add KEXEC_SIG support Michal Suchanek
2021-12-09 1:51 ` Nayna
2021-12-09 9:21 ` Michal Suchánek
2021-12-09 21:53 ` Nayna
2021-12-11 23:37 ` Nayna
2021-12-13 0:46 ` Nayna
2021-12-13 18:18 ` Michal Suchánek
2021-11-25 18:02 ` [PATCH v2 3/6] kexec_file: Don't opencode appended signature verification Michal Suchanek
2021-11-25 18:02 ` Michal Suchanek [this message]
2021-12-07 16:11 ` [PATCH v2 4/6] module: strip the signature marker in the verification function Philipp Rudo
2021-11-25 18:02 ` [PATCH v2 5/6] module: Use key_being_used_for for log messages in verify_appended_signature Michal Suchanek
2021-11-25 18:02 ` [PATCH v2 6/6] module: Move duplicate mod_check_sig users code to mod_parse_sig Michal Suchanek
2021-12-07 16:10 ` Philipp Rudo
2021-12-13 18:06 ` Michal Suchánek
2021-11-30 15:28 ` [PATCH v2 0/6] KEXEC_SIG with appended signature Heiko Carstens
2021-12-01 2:37 ` Baoquan He
2021-12-01 11:48 ` Michal Suchánek
2021-12-07 16:10 ` Philipp Rudo
2021-12-07 17:32 ` Michal Suchánek
2021-12-08 9:54 ` Philipp Rudo
2021-12-09 1:50 ` Nayna
2021-12-09 14:57 ` Michal Suchánek
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