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

Roberto Sassu
2021-05-20T08:57:27Z

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@huawei.com>
---
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