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From: Matthew Garrett <matthewgarrett@google.com>
To: linux-integrity@vger.kernel.org
Cc: zohar@linux.vnet.ibm.com, dmitry.kasatkin@gmail.com,
	miklos@szeredi.hu, linux-fsdevel@vger.kernel.org,
	viro@zeniv.linux.org.uk,
	Matthew Garrett <matthewgarrett@google.com>,
	Matthew Garrett <mjg59@google.com>
Subject: [PATCH V3 3/6] IMA: Allow rule matching on filesystem subtype
Date: Fri, 17 May 2019 14:24:45 -0700
Message-ID: <20190517212448.14256-4-matthewgarrett@google.com> (raw)
In-Reply-To: <20190517212448.14256-1-matthewgarrett@google.com>

IMA currently allows rules to match on the filesystem type. Certain
filesystem types permit subtypes (eg, fuse). Add support to IMA to allow
rules to match on subtypes as well as types.

Signed-off-by: Matthew Garrett <mjg59@google.com>
---
 Documentation/ABI/testing/ima_policy |  4 +++-
 security/integrity/ima/ima_policy.c  | 26 +++++++++++++++++++++++++-
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
index 74c6702de74e..09a5def7e28a 100644
--- a/Documentation/ABI/testing/ima_policy
+++ b/Documentation/ABI/testing/ima_policy
@@ -21,7 +21,7 @@ Description:
 			audit | hash | dont_hash
 		condition:= base | lsm  [option]
 			base:	[[func=] [mask=] [fsmagic=] [fsuuid=] [uid=]
-				[euid=] [fowner=] [fsname=]]
+				[euid=] [fowner=] [fsname=] [subtype=]]
 			lsm:	[[subj_user=] [subj_role=] [subj_type=]
 				 [obj_user=] [obj_role=] [obj_type=]]
 			option:	[[appraise_type=]] [permit_directio]
@@ -33,6 +33,8 @@ Description:
 			       [[^]MAY_EXEC]
 			fsmagic:= hex value
 			fsuuid:= file system UUID (e.g 8bcbe394-4f13-4144-be8e-5aa9ea2ce2f6)
+			fsname:= file system type (e.g fuse)
+			subtype:= file system subtype (e.g ntfs3g)
 			uid:= decimal value
 			euid:= decimal value
 			fowner:= decimal value
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index e0cc323f948f..bb4e265823a7 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -35,6 +35,7 @@
 #define IMA_EUID	0x0080
 #define IMA_PCR		0x0100
 #define IMA_FSNAME	0x0200
+#define IMA_SUBTYPE	0x0400
 
 #define UNKNOWN		0
 #define MEASURE		0x0001	/* same as IMA_MEASURE */
@@ -80,6 +81,7 @@ struct ima_rule_entry {
 		int type;	/* audit type */
 	} lsm[MAX_LSM_RULES];
 	char *fsname;
+	char *subtype;
 };
 
 /*
@@ -306,6 +308,10 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
 	if ((rule->flags & IMA_FSNAME)
 	    && strcmp(rule->fsname, inode->i_sb->s_type->name))
 		return false;
+	if ((rule->flags & IMA_SUBTYPE)
+	    && (inode->i_sb->s_subtype == NULL ||
+		strcmp(rule->subtype, inode->i_sb->s_subtype)))
+		return false;
 	if ((rule->flags & IMA_FSUUID) &&
 	    !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
 		return false;
@@ -670,7 +676,7 @@ enum {
 	Opt_audit, Opt_hash, Opt_dont_hash,
 	Opt_obj_user, Opt_obj_role, Opt_obj_type,
 	Opt_subj_user, Opt_subj_role, Opt_subj_type,
-	Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname,
+	Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname, Opt_subtype,
 	Opt_fsuuid, Opt_uid_eq, Opt_euid_eq, Opt_fowner_eq,
 	Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt,
 	Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
@@ -696,6 +702,7 @@ static const match_table_t policy_tokens = {
 	{Opt_mask, "mask=%s"},
 	{Opt_fsmagic, "fsmagic=%s"},
 	{Opt_fsname, "fsname=%s"},
+	{Opt_subtype, "subtype=%s"},
 	{Opt_fsuuid, "fsuuid=%s"},
 	{Opt_uid_eq, "uid=%s"},
 	{Opt_euid_eq, "euid=%s"},
@@ -921,6 +928,17 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 			result = 0;
 			entry->flags |= IMA_FSNAME;
 			break;
+		case Opt_subtype:
+			ima_log_string(ab, "subtype", args[0].from);
+
+			entry->subtype = kstrdup(args[0].from, GFP_KERNEL);
+			if (!entry->subtype) {
+				result = -ENOMEM;
+				break;
+			}
+			result = 0;
+			entry->flags |= IMA_SUBTYPE;
+			break;
 		case Opt_fsuuid:
 			ima_log_string(ab, "fsuuid", args[0].from);
 
@@ -1256,6 +1274,12 @@ int ima_policy_show(struct seq_file *m, void *v)
 		seq_puts(m, " ");
 	}
 
+	if (entry->flags & IMA_SUBTYPE) {
+		snprintf(tbuf, sizeof(tbuf), "%s", entry->subtype);
+		seq_printf(m, pt(Opt_subtype), tbuf);
+		seq_puts(m, " ");
+	}
+
 	if (entry->flags & IMA_PCR) {
 		snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
 		seq_printf(m, pt(Opt_pcr), tbuf);
-- 
2.21.0.1020.gf2820cf01a-goog


  parent reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-17 21:24 [PATCH V3 0/6] IMA: Support asking the VFS for a file hash Matthew Garrett
2019-05-17 21:24 ` [PATCH V3 1/6] VFS: Add a call to obtain a file's hash Matthew Garrett
2019-05-18 11:25   ` kbuild test robot
2019-05-20  7:10   ` Johannes Thumshirn
2019-05-17 21:24 ` [PATCH V3 2/6] FUSE: Allow filesystems to provide gethash methods Matthew Garrett
2019-05-17 21:24 ` Matthew Garrett [this message]
2019-05-17 21:24 ` [PATCH V3 4/6] IMA: Optionally make use of filesystem-provided hashes Matthew Garrett
2019-05-17 21:24 ` [PATCH V3 5/6] IMA: Add a ima-vfs-sig measurement template Matthew Garrett
2019-05-18 10:04   ` kbuild test robot
2019-05-17 21:24 ` [PATCH V3 6/6] IMA: Allow profiles to define the desired IMA template Matthew Garrett
2019-05-17 23:47   ` Mimi Zohar
2019-05-20 20:59     ` Matthew Garrett
2019-05-20 21:26       ` Mimi Zohar
2019-05-21  0:10         ` prakhar srivastava

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