[PATCH 4/7] ima: Introduce template field imode

[Roberto Sassu <roberto.sassu@xxxxxxxxxx>]

This patch introduces the new template field imode, which includes the
inode mode. It can be used by a remote verifier to verify the EVM portable
signature, if it was included with the template fields sig or evmsig.

Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
---
 Documentation/security/IMA-templates.rst  |  1 +
 security/integrity/ima/ima_template.c     |  2 ++
 security/integrity/ima/ima_template_lib.c | 22 ++++++++++++++++++++++
 security/integrity/ima/ima_template_lib.h |  2 ++
 4 files changed, 27 insertions(+)

diff --git a/Documentation/security/IMA-templates.rst b/Documentation/security/IMA-templates.rst
index 48a2df22a1a1..6e98bce20029 100644
--- a/Documentation/security/IMA-templates.rst
+++ b/Documentation/security/IMA-templates.rst
@@ -81,6 +81,7 @@ descriptors by adding their identifier to the format string
     [ uid_gid_extent1 ] ... [ uid_gid_extentN ], all u32 in canonical format);
  - 'mntgidmap': the GID mappings of the idmapped mount (same format as
    'mntuidmap');
+ - 'imode': the inode mode;
 
 
 Below, there is the list of defined template descriptors:
diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
index 19de115b985b..34674aef1cc5 100644
--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c
@@ -57,6 +57,8 @@ static const struct ima_template_field supported_fields[] = {
 	{.field_id = "mntgidmap",
 	 .field_init = ima_eventmnt_userns_gid_map_init,
 	 .field_show = ima_show_template_sig},
+	{.field_id = "imode", .field_init = ima_eventinodemode_init,
+	 .field_show = ima_show_template_uint},
 };
 
 /*
diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c
index bc4919d90c3a..b82fb8f35e5d 100644
--- a/security/integrity/ima/ima_template_lib.c
+++ b/security/integrity/ima/ima_template_lib.c
@@ -692,3 +692,25 @@ int ima_eventmnt_userns_gid_map_init(struct ima_event_data *event_data,
 {
 	return ima_eventmnt_userns_common_init(event_data, field_data, false);
 }
+
+/*
+ *  ima_eventinodemode_init - include the inode mode as part of the template
+ *  data
+ */
+int ima_eventinodemode_init(struct ima_event_data *event_data,
+			    struct ima_field_data *field_data)
+{
+	struct inode *inode;
+	umode_t mode;
+
+	if (!event_data->file)
+		return 0;
+
+	inode = file_inode(event_data->file);
+	mode = inode->i_mode;
+	if (ima_canonical_fmt)
+		mode = cpu_to_le16(mode);
+
+	return ima_write_template_field_data((char *)&mode, sizeof(mode),
+					     DATA_FMT_UINT, field_data);
+}
diff --git a/security/integrity/ima/ima_template_lib.h b/security/integrity/ima/ima_template_lib.h
index 51ee66fc7230..dc3c16912f6d 100644
--- a/security/integrity/ima/ima_template_lib.h
+++ b/security/integrity/ima/ima_template_lib.h
@@ -58,4 +58,6 @@ int ima_eventmnt_userns_uid_map_init(struct ima_event_data *event_data,
 				     struct ima_field_data *field_data);
 int ima_eventmnt_userns_gid_map_init(struct ima_event_data *event_data,
 				     struct ima_field_data *field_data);
+int ima_eventinodemode_init(struct ima_event_data *event_data,
+			    struct ima_field_data *field_data);
 #endif /* __LINUX_IMA_TEMPLATE_LIB_H */
-- 
2.25.1