There is one more copy of the code checking appended signarutes.
Merge the common code to module_signature.c
Thanks
Michal
Michal Suchanek (2):
module: Use key_being_used_for for log messages in
verify_appended_signature
module: Move duplicate mod_check_sig users code to mod_parse_sig
arch/powerpc/kexec/elf_64.c | 2 +-
arch/s390/kernel/machine_kexec_file.c | 2 +-
crypto/asymmetric_keys/asymmetric_type.c | 1 +
include/linux/module_signature.h | 1 +
include/linux/verification.h | 3 +-
kernel/module.c | 3 +-
kernel/module_signature.c | 56 +++++++++++++++++++++++-
kernel/module_signing.c | 33 ++++----------
security/integrity/ima/ima_modsig.c | 22 ++--------
9 files changed, 74 insertions(+), 49 deletions(-)
--
2.31.1
Multiple users of mod_check_sig check for the marker, then call
mod_check_sig, extract signature length, and remove the signature.
Put this code in one place together with mod_check_sig.
Signed-off-by: Michal Suchanek <[email protected]>
---
include/linux/module_signature.h | 1 +
kernel/module_signature.c | 56 ++++++++++++++++++++++++++++-
kernel/module_signing.c | 26 +++-----------
security/integrity/ima/ima_modsig.c | 22 ++----------
4 files changed, 63 insertions(+), 42 deletions(-)
diff --git a/include/linux/module_signature.h b/include/linux/module_signature.h
index 7eb4b00381ac..1343879b72b3 100644
--- a/include/linux/module_signature.h
+++ b/include/linux/module_signature.h
@@ -42,5 +42,6 @@ struct module_signature {
int mod_check_sig(const struct module_signature *ms, size_t file_len,
const char *name);
+int mod_parse_sig(const void *data, size_t *len, size_t *sig_len, const char *name);
#endif /* _LINUX_MODULE_SIGNATURE_H */
diff --git a/kernel/module_signature.c b/kernel/module_signature.c
index 00132d12487c..784b40575ee4 100644
--- a/kernel/module_signature.c
+++ b/kernel/module_signature.c
@@ -8,14 +8,36 @@
#include <linux/errno.h>
#include <linux/printk.h>
+#include <linux/string.h>
#include <linux/module_signature.h>
#include <asm/byteorder.h>
+/**
+ * mod_check_sig_marker - check that the given data has signature marker at the end
+ *
+ * @data: Data with appended signature
+ * @len: Length of data. Signature marker length is subtracted on success.
+ */
+static inline int mod_check_sig_marker(const void *data, size_t *len)
+{
+ const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
+
+ if (markerlen > *len)
+ return -ENODATA;
+
+ if (memcmp(data + *len - markerlen, MODULE_SIG_STRING,
+ markerlen))
+ return -ENODATA;
+
+ *len -= markerlen;
+ return 0;
+}
+
/**
* mod_check_sig - check that the given signature is sane
*
* @ms: Signature to check.
- * @file_len: Size of the file to which @ms is appended.
+ * @file_len: Size of the file to which @ms is appended (without the marker).
* @name: What is being checked. Used for error messages.
*/
int mod_check_sig(const struct module_signature *ms, size_t file_len,
@@ -44,3 +66,35 @@ int mod_check_sig(const struct module_signature *ms, size_t file_len,
return 0;
}
+
+/**
+ * mod_parse_sig - check that the given signature is sane and determine signature length
+ *
+ * @data: Data with appended signature.
+ * @len: Length of data. Signature and marker length is subtracted on success.
+ * @sig_len: Length of signature. Filled on success.
+ * @name: What is being checked. Used for error messages.
+ */
+int mod_parse_sig(const void *data, size_t *len, size_t *sig_len, const char *name)
+{
+ const struct module_signature *sig;
+ int rc;
+
+ rc = mod_check_sig_marker(data, len);
+ if (rc)
+ return rc;
+
+ if (*len < sizeof(*sig))
+ return -ENODATA;
+
+ sig = (const struct module_signature *)(data + (*len - sizeof(*sig)));
+
+ rc = mod_check_sig(sig, *len, name);
+ if (rc)
+ return rc;
+
+ *sig_len = be32_to_cpu(sig->sig_len);
+ *len -= *sig_len + sizeof(*sig);
+
+ return 0;
+}
diff --git a/kernel/module_signing.c b/kernel/module_signing.c
index cef72a6f6b5d..02bbca90f467 100644
--- a/kernel/module_signing.c
+++ b/kernel/module_signing.c
@@ -25,35 +25,17 @@ int verify_appended_signature(const void *data, size_t *len,
struct key *trusted_keys,
enum key_being_used_for purpose)
{
- const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
struct module_signature ms;
- size_t sig_len, modlen = *len;
+ size_t sig_len;
int ret;
- pr_devel("==>%s %s(,%zu)\n", __func__, key_being_used_for[purpose], modlen);
+ pr_devel("==>%s %s(,%zu)\n", __func__, key_being_used_for[purpose], *len);
- if (markerlen > modlen)
- return -ENODATA;
-
- if (memcmp(data + modlen - markerlen, MODULE_SIG_STRING,
- markerlen))
- return -ENODATA;
- modlen -= markerlen;
-
- if (modlen <= sizeof(ms))
- return -EBADMSG;
-
- memcpy(&ms, data + (modlen - sizeof(ms)), sizeof(ms));
-
- ret = mod_check_sig(&ms, modlen, key_being_used_for[purpose]);
+ ret = mod_parse_sig(data, len, &sig_len, key_being_used_for[purpose]);
if (ret)
return ret;
- sig_len = be32_to_cpu(ms.sig_len);
- modlen -= sig_len + sizeof(ms);
- *len = modlen;
-
- return verify_pkcs7_signature(data, modlen, data + modlen, sig_len,
+ return verify_pkcs7_signature(data, *len, data + *len, sig_len,
trusted_keys,
purpose,
NULL, NULL);
diff --git a/security/integrity/ima/ima_modsig.c b/security/integrity/ima/ima_modsig.c
index fb25723c65bc..46917eb37fd8 100644
--- a/security/integrity/ima/ima_modsig.c
+++ b/security/integrity/ima/ima_modsig.c
@@ -37,33 +37,17 @@ struct modsig {
*
* Return: 0 on success, error code otherwise.
*/
-int ima_read_modsig(enum ima_hooks func, const void *buf, loff_t buf_len,
+int ima_read_modsig(enum ima_hooks func, const void *buf, loff_t len,
struct modsig **modsig)
{
- const size_t marker_len = strlen(MODULE_SIG_STRING);
- const struct module_signature *sig;
struct modsig *hdr;
- size_t sig_len;
- const void *p;
+ size_t sig_len, buf_len = len;
int rc;
- if (buf_len <= marker_len + sizeof(*sig))
- return -ENOENT;
-
- p = buf + buf_len - marker_len;
- if (memcmp(p, MODULE_SIG_STRING, marker_len))
- return -ENOENT;
-
- buf_len -= marker_len;
- sig = (const struct module_signature *)(p - sizeof(*sig));
-
- rc = mod_check_sig(sig, buf_len, func_tokens[func]);
+ rc = mod_parse_sig(buf, &buf_len, &sig_len, func_tokens[func]);
if (rc)
return rc;
- sig_len = be32_to_cpu(sig->sig_len);
- buf_len -= sig_len + sizeof(*sig);
-
/* Allocate sig_len additional bytes to hold the raw PKCS#7 data. */
hdr = kzalloc(sizeof(*hdr) + sig_len, GFP_KERNEL);
if (!hdr)
--
2.31.1
Add value for kexec appended signature and pass in key_being_used_for
enum rather than a string to verify_appended_signature to produce log
messages about the signature.
Signed-off-by: Michal Suchanek <[email protected]>
---
arch/powerpc/kexec/elf_64.c | 2 +-
arch/s390/kernel/machine_kexec_file.c | 2 +-
crypto/asymmetric_keys/asymmetric_type.c | 1 +
include/linux/verification.h | 3 ++-
kernel/module.c | 3 ++-
kernel/module_signing.c | 11 ++++++-----
6 files changed, 13 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/kexec/elf_64.c b/arch/powerpc/kexec/elf_64.c
index e8dff6b23ac5..3aa5269f6e0f 100644
--- a/arch/powerpc/kexec/elf_64.c
+++ b/arch/powerpc/kexec/elf_64.c
@@ -158,7 +158,7 @@ int elf64_verify_sig(const char *kernel, unsigned long length)
size_t kernel_len = length;
return verify_appended_signature(kernel, &kernel_len, VERIFY_USE_PLATFORM_KEYRING,
- "kexec_file");
+ VERIFYING_KEXEC_APPENDED_SIGNATURE);
}
#endif /* CONFIG_KEXEC_SIG */
diff --git a/arch/s390/kernel/machine_kexec_file.c b/arch/s390/kernel/machine_kexec_file.c
index 82260bb61060..37fcbb149368 100644
--- a/arch/s390/kernel/machine_kexec_file.c
+++ b/arch/s390/kernel/machine_kexec_file.c
@@ -32,7 +32,7 @@ int s390_verify_sig(const char *kernel, unsigned long length)
return 0;
return verify_appended_signature(kernel, &kernel_len, VERIFY_USE_PLATFORM_KEYRING,
- "kexec_file");
+ VERIFYING_KEXEC_APPENDED_SIGNATURE);
}
#endif /* CONFIG_KEXEC_SIG */
diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c
index ad8af3d70ac0..6fd20eec3882 100644
--- a/crypto/asymmetric_keys/asymmetric_type.c
+++ b/crypto/asymmetric_keys/asymmetric_type.c
@@ -25,6 +25,7 @@ const char *const key_being_used_for[NR__KEY_BEING_USED_FOR] = {
[VERIFYING_KEXEC_PE_SIGNATURE] = "kexec PE sig",
[VERIFYING_KEY_SIGNATURE] = "key sig",
[VERIFYING_KEY_SELF_SIGNATURE] = "key self sig",
+ [VERIFYING_KEXEC_APPENDED_SIGNATURE] = "kexec appended sig",
[VERIFYING_UNSPECIFIED_SIGNATURE] = "unspec sig",
};
EXPORT_SYMBOL_GPL(key_being_used_for);
diff --git a/include/linux/verification.h b/include/linux/verification.h
index c1cf0582012a..23748feb9e03 100644
--- a/include/linux/verification.h
+++ b/include/linux/verification.h
@@ -26,6 +26,7 @@ enum key_being_used_for {
VERIFYING_KEXEC_PE_SIGNATURE,
VERIFYING_KEY_SIGNATURE,
VERIFYING_KEY_SELF_SIGNATURE,
+ VERIFYING_KEXEC_APPENDED_SIGNATURE,
VERIFYING_UNSPECIFIED_SIGNATURE,
NR__KEY_BEING_USED_FOR
};
@@ -61,7 +62,7 @@ extern int verify_pefile_signature(const void *pebuf, unsigned pelen,
#endif
int verify_appended_signature(const void *data, size_t *len, struct key *trusted_keys,
- const char *what);
+ enum key_being_used_for purpose);
#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
#endif /* _LINUX_VERIFY_PEFILE_H */
diff --git a/kernel/module.c b/kernel/module.c
index 1c421b0442e3..5f1cf989e1cf 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2891,7 +2891,8 @@ static int module_sig_check(struct load_info *info, int flags)
*/
if (flags == 0) {
err = verify_appended_signature(mod, &info->len,
- VERIFY_USE_SECONDARY_KEYRING, "module");
+ VERIFY_USE_SECONDARY_KEYRING,
+ VERIFYING_MODULE_SIGNATURE);
if (!err) {
info->sig_ok = true;
return 0;
diff --git a/kernel/module_signing.c b/kernel/module_signing.c
index 4c28cb55275f..cef72a6f6b5d 100644
--- a/kernel/module_signing.c
+++ b/kernel/module_signing.c
@@ -19,17 +19,18 @@
* @data: The data to be verified
* @len: Size of @data.
* @trusted_keys: Keyring to use for verification
- * @what: Informational string for log messages
+ * @purpose: The use to which the key is being put
*/
int verify_appended_signature(const void *data, size_t *len,
- struct key *trusted_keys, const char *what)
+ struct key *trusted_keys,
+ enum key_being_used_for purpose)
{
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);
+ pr_devel("==>%s %s(,%zu)\n", __func__, key_being_used_for[purpose], modlen);
if (markerlen > modlen)
return -ENODATA;
@@ -44,7 +45,7 @@ int verify_appended_signature(const void *data, size_t *len,
memcpy(&ms, data + (modlen - sizeof(ms)), sizeof(ms));
- ret = mod_check_sig(&ms, modlen, what);
+ ret = mod_check_sig(&ms, modlen, key_being_used_for[purpose]);
if (ret)
return ret;
@@ -54,6 +55,6 @@ int verify_appended_signature(const void *data, size_t *len,
return verify_pkcs7_signature(data, modlen, data + modlen, sig_len,
trusted_keys,
- VERIFYING_MODULE_SIGNATURE,
+ purpose,
NULL, NULL);
}
--
2.31.1