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authorRoberto Sassu <roberto.sassu@huawei.com>2021-05-14 17:27:52 +0200
committerMimi Zohar <zohar@linux.ibm.com>2021-06-01 12:30:51 -0400
commit026d7fc92a9d629630779c999fe49ecae93f9d63 (patch)
treee54222a44f2739b05f274e68ed87a84d86e75e97 /security
parent7aa5783d95646f924b99d245338d5b7aa7a2b3c0 (diff)
ima: Introduce template field evmsig and write to field sig as fallback
With the patch to accept EVM portable signatures when the appraise_type=imasig requirement is specified in the policy, appraisal can be successfully done even if the file does not have an IMA signature. However, remote attestation would not see that a different signature type was used, as only IMA signatures can be included in the measurement list. This patch solves the issue by introducing the new template field 'evmsig' to show EVM portable signatures and by including its value in the existing field 'sig' if the IMA signature is not found. Suggested-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Diffstat (limited to 'security')
-rw-r--r--security/integrity/ima/ima_template.c2
-rw-r--r--security/integrity/ima/ima_template_lib.c33
-rw-r--r--security/integrity/ima/ima_template_lib.h2
3 files changed, 36 insertions, 1 deletions
diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
index 4e081e650047..7a60848c04a5 100644
--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c
@@ -45,6 +45,8 @@ static const struct ima_template_field supported_fields[] = {
.field_show = ima_show_template_digest_ng},
{.field_id = "modsig", .field_init = ima_eventmodsig_init,
.field_show = ima_show_template_sig},
+ {.field_id = "evmsig", .field_init = ima_eventevmsig_init,
+ .field_show = ima_show_template_sig},
};
/*
diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c
index c022ee9e2a4e..4314d9a3514c 100644
--- a/security/integrity/ima/ima_template_lib.c
+++ b/security/integrity/ima/ima_template_lib.c
@@ -10,6 +10,7 @@
*/
#include "ima_template_lib.h"
+#include <linux/xattr.h>
static bool ima_template_hash_algo_allowed(u8 algo)
{
@@ -438,7 +439,7 @@ int ima_eventsig_init(struct ima_event_data *event_data,
struct evm_ima_xattr_data *xattr_value = event_data->xattr_value;
if ((!xattr_value) || (xattr_value->type != EVM_IMA_XATTR_DIGSIG))
- return 0;
+ return ima_eventevmsig_init(event_data, field_data);
return ima_write_template_field_data(xattr_value, event_data->xattr_len,
DATA_FMT_HEX, field_data);
@@ -484,3 +485,33 @@ int ima_eventmodsig_init(struct ima_event_data *event_data,
return ima_write_template_field_data(data, data_len, DATA_FMT_HEX,
field_data);
}
+
+/*
+ * ima_eventevmsig_init - include the EVM portable signature as part of the
+ * template data
+ */
+int ima_eventevmsig_init(struct ima_event_data *event_data,
+ struct ima_field_data *field_data)
+{
+ struct evm_ima_xattr_data *xattr_data = NULL;
+ int rc = 0;
+
+ if (!event_data->file)
+ return 0;
+
+ rc = vfs_getxattr_alloc(&init_user_ns, file_dentry(event_data->file),
+ XATTR_NAME_EVM, (char **)&xattr_data, 0,
+ GFP_NOFS);
+ if (rc <= 0)
+ return 0;
+
+ if (xattr_data->type != EVM_XATTR_PORTABLE_DIGSIG) {
+ kfree(xattr_data);
+ return 0;
+ }
+
+ rc = ima_write_template_field_data((char *)xattr_data, rc, DATA_FMT_HEX,
+ field_data);
+ kfree(xattr_data);
+ return rc;
+}
diff --git a/security/integrity/ima/ima_template_lib.h b/security/integrity/ima/ima_template_lib.h
index 6b3b880637a0..f4b2a2056d1d 100644
--- a/security/integrity/ima/ima_template_lib.h
+++ b/security/integrity/ima/ima_template_lib.h
@@ -46,4 +46,6 @@ int ima_eventbuf_init(struct ima_event_data *event_data,
struct ima_field_data *field_data);
int ima_eventmodsig_init(struct ima_event_data *event_data,
struct ima_field_data *field_data);
+int ima_eventevmsig_init(struct ima_event_data *event_data,
+ struct ima_field_data *field_data);
#endif /* __LINUX_IMA_TEMPLATE_LIB_H */