The upcoming CONFIG_MODULE_HASHES will introduce a signature type.
This needs to be handled by callers differently than PKCS7 signatures.
Report the signature type to the caller and let them verify it.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
include/linux/module_signature.h | 2 +-
kernel/module/main.c | 9 +++++++--
kernel/module_signature.c | 14 ++++----------
security/integrity/ima/ima_modsig.c | 8 +++++++-
4 files changed, 19 insertions(+), 14 deletions(-)
diff --git a/include/linux/module_signature.h b/include/linux/module_signature.h
index 186a55effa30..a45ce3b24403 100644
--- a/include/linux/module_signature.h
+++ b/include/linux/module_signature.h
@@ -41,6 +41,6 @@ struct module_signature {
};
int mod_split_sig(const void *buf, size_t *buf_len, bool mangled,
- size_t *sig_len, const u8 **sig, const char *name);
+ enum pkey_id_type *sig_type, size_t *sig_len, const u8 **sig, const char *name);
#endif /* _LINUX_MODULE_SIGNATURE_H */
diff --git a/kernel/module/main.c b/kernel/module/main.c
index d65bc300a78c..2a28a0ece809 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -3348,19 +3348,24 @@ static int module_integrity_check(struct load_info *info, int flags)
{
bool mangled_module = flags & (MODULE_INIT_IGNORE_MODVERSIONS |
MODULE_INIT_IGNORE_VERMAGIC);
+ enum pkey_id_type sig_type;
size_t sig_len;
const u8 *sig;
int err = 0;
if (IS_ENABLED(CONFIG_MODULE_SIG_POLICY)) {
err = mod_split_sig(info->hdr, &info->len, mangled_module,
- &sig_len, &sig, "module");
+ &sig_type, &sig_len, &sig, "module");
if (err)
return err;
}
- if (IS_ENABLED(CONFIG_MODULE_SIG))
+ if (IS_ENABLED(CONFIG_MODULE_SIG) && sig_type == PKEY_ID_PKCS7) {
err = module_sig_check(info, sig, sig_len);
+ } else {
+ pr_err("module: not signed with expected PKCS#7 message\n");
+ err = -ENOPKG;
+ }
if (err)
return err;
diff --git a/kernel/module_signature.c b/kernel/module_signature.c
index b2384a73524c..8e0ac9906c9c 100644
--- a/kernel/module_signature.c
+++ b/kernel/module_signature.c
@@ -19,18 +19,11 @@
* @file_len: Size of the file to which @ms is appended.
* @name: What is being checked. Used for error messages.
*/
-static int mod_check_sig(const struct module_signature *ms, size_t file_len,
- const char *name)
+static int mod_check_sig(const struct module_signature *ms, size_t file_len, const char *name)
{
if (be32_to_cpu(ms->sig_len) >= file_len - sizeof(*ms))
return -EBADMSG;
- if (ms->id_type != PKEY_ID_PKCS7) {
- pr_err("%s: not signed with expected PKCS#7 message\n",
- name);
- return -ENOPKG;
- }
-
if (ms->algo != 0 ||
ms->hash != 0 ||
ms->signer_len != 0 ||
@@ -38,7 +31,7 @@ static int mod_check_sig(const struct module_signature *ms, size_t file_len,
ms->__pad[0] != 0 ||
ms->__pad[1] != 0 ||
ms->__pad[2] != 0) {
- pr_err("%s: PKCS#7 signature info has unexpected non-zero params\n",
+ pr_err("%s: signature info has unexpected non-zero params\n",
name);
return -EBADMSG;
}
@@ -47,7 +40,7 @@ static int mod_check_sig(const struct module_signature *ms, size_t file_len,
}
int mod_split_sig(const void *buf, size_t *buf_len, bool mangled,
- size_t *sig_len, const u8 **sig, const char *name)
+ enum pkey_id_type *sig_type, size_t *sig_len, const u8 **sig, const char *name)
{
const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
struct module_signature ms;
@@ -74,6 +67,7 @@ int mod_split_sig(const void *buf, size_t *buf_len, bool mangled,
if (ret)
return ret;
+ *sig_type = ms.id_type;
*sig_len = be32_to_cpu(ms.sig_len);
modlen -= *sig_len + sizeof(ms);
*buf_len = modlen;
diff --git a/security/integrity/ima/ima_modsig.c b/security/integrity/ima/ima_modsig.c
index a57342d39b07..a05008324a10 100644
--- a/security/integrity/ima/ima_modsig.c
+++ b/security/integrity/ima/ima_modsig.c
@@ -41,15 +41,21 @@ int ima_read_modsig(enum ima_hooks func, const void *buf, loff_t buf_len,
struct modsig **modsig)
{
size_t buf_len_sz = buf_len;
+ enum pkey_id_type sig_type;
struct modsig *hdr;
size_t sig_len;
const u8 *sig;
int rc;
- rc = mod_split_sig(buf, &buf_len_sz, true, &sig_len, &sig, func_tokens[func]);
+ rc = mod_split_sig(buf, &buf_len_sz, true, &sig_type, &sig_len, &sig, func_tokens[func]);
if (rc)
return rc;
+ if (sig_type != PKEY_ID_PKCS7) {
+ pr_err("%s: not signed with expected PKCS#7 message\n", func_tokens[func]);
+ return -ENOPKG;
+ }
+
/* Allocate sig_len additional bytes to hold the raw PKCS#7 data. */
hdr = kzalloc(struct_size(hdr, raw_pkcs7, sig_len), GFP_KERNEL);
if (!hdr)
--
2.52.0