integrity-v6.19

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Merge tag 'integrity-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull integrity updates from Mimi Zohar:
 "Bug fixes:

   - defer credentials checking from the bprm_check_security hook to the
     bprm_creds_from_file security hook

   - properly ignore IMA policy rules based on undefined SELinux labels

  IMA policy rule extensions:

   - extend IMA to limit including file hashes in the audit logs
     (dont_audit action)

   - define a new filesystem subtype policy option (fs_subtype)

  Misc:

   - extend IMA to support in-kernel module decompression by deferring
     the IMA signature verification in kernel_read_file() to after the
     kernel module is decompressed"

* tag 'integrity-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  ima: Handle error code returned by ima_filter_rule_match()
  ima: Access decompressed kernel module to verify appended signature
  ima: add fs_subtype condition for distinguishing FUSE instances
  ima: add dont_audit action to suppress audit actions
  ima: Attach CREDS_CHECK IMA hook to bprm_creds_from_file LSM hook

Documentation/ABI/testing/ima_policy

@@ -20,9 +20,10 @@ Description:
 		  rule format: action [condition ...]
 
 		  action: measure | dont_measure | appraise | dont_appraise |
-			  audit | hash | dont_hash
+			  audit | dont_audit | hash | dont_hash
 		  condition:= base | lsm  [option]
 			base:	[[func=] [mask=] [fsmagic=] [fsuuid=] [fsname=]
+				[fs_subtype=]
 				[uid=] [euid=] [gid=] [egid=]
 				[fowner=] [fgroup=]]
 			lsm:	[[subj_user=] [subj_role=] [subj_type=]

include/linux/kernel_read_file.h

@@ -14,6 +14,7 @@
 	id(KEXEC_INITRAMFS, kexec-initramfs)	\
 	id(POLICY, security-policy)		\
 	id(X509_CERTIFICATE, x509-certificate)	\
+	id(MODULE_COMPRESSED, kernel-module-compressed) \
 	id(MAX_ID, )
 
 #define __fid_enumify(ENUM, dummy) READING_ ## ENUM,

kernel/module/main.c

@@ -3675,24 +3675,35 @@ static int idempotent_wait_for_completion(struct idempotent *u)
 
 static int init_module_from_file(struct file *f, const char __user * uargs, int flags)
 {
+	bool compressed = !!(flags & MODULE_INIT_COMPRESSED_FILE);
 	struct load_info info = { };
 	void *buf = NULL;
 	int len;
+	int err;
 
-	len = kernel_read_file(f, 0, &buf, INT_MAX, NULL, READING_MODULE);
+	len = kernel_read_file(f, 0, &buf, INT_MAX, NULL,
+			       compressed ? READING_MODULE_COMPRESSED :
+					    READING_MODULE);
 	if (len < 0) {
 		mod_stat_inc(&failed_kreads);
 		return len;
 	}
 
-	if (flags & MODULE_INIT_COMPRESSED_FILE) {
-		int err = module_decompress(&info, buf, len);
+	if (compressed) {
+		err = module_decompress(&info, buf, len);
 		vfree(buf); /* compressed data is no longer needed */
 		if (err) {
 			mod_stat_inc(&failed_decompress);
 			mod_stat_add_long(len, &invalid_decompress_bytes);
 			return err;
 		}
+		err = security_kernel_post_read_file(f, (char *)info.hdr, info.len,
+						     READING_MODULE);
+		if (err) {
+			mod_stat_inc(&failed_kreads);
+			free_copy(&info, flags);
+			return err;
+		}
 	} else {
 		info.hdr = buf;
 		info.len = len;

security/integrity/ima/ima_main.c

@@ -235,7 +235,8 @@ static void ima_file_free(struct file *file)
 
 static int process_measurement(struct file *file, const struct cred *cred,
 			       struct lsm_prop *prop, char *buf, loff_t size,
-			       int mask, enum ima_hooks func)
+			       int mask, enum ima_hooks func,
+			       enum kernel_read_file_id read_id)
 {
 	struct inode *real_inode, *inode = file_inode(file);
 	struct ima_iint_cache *iint = NULL;
@@ -406,6 +407,12 @@ static int process_measurement(struct file *file, const struct cred *cred,
 	if (rc != 0 && rc != -EBADF && rc != -EINVAL)
 		goto out_locked;
 
+	/* Defer measuring/appraising kernel modules to READING_MODULE */
+	if (read_id == READING_MODULE_COMPRESSED) {
+		must_appraise = 0;
+		goto out_locked;
+	}
+
 	if (!pathbuf)	/* ima_rdwr_violation possibly pre-fetched */
 		pathname = ima_d_path(&file->f_path, &pathbuf, filename);
 
@@ -486,14 +493,14 @@ static int ima_file_mmap(struct file *file, unsigned long reqprot,
 
 	if (reqprot & PROT_EXEC) {
 		ret = process_measurement(file, current_cred(), &prop, NULL,
-					  0, MAY_EXEC, MMAP_CHECK_REQPROT);
+					  0, MAY_EXEC, MMAP_CHECK_REQPROT, 0);
 		if (ret)
 			return ret;
 	}
 
 	if (prot & PROT_EXEC)
 		return process_measurement(file, current_cred(), &prop, NULL,
-					   0, MAY_EXEC, MMAP_CHECK);
+					   0, MAY_EXEC, MMAP_CHECK, 0);
 
 	return 0;
 }
@@ -573,18 +580,41 @@ static int ima_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot,
  */
 static int ima_bprm_check(struct linux_binprm *bprm)
 {
-	int ret;
 	struct lsm_prop prop;
 
 	security_current_getlsmprop_subj(&prop);
-	ret = process_measurement(bprm->file, current_cred(),
-				  &prop, NULL, 0, MAY_EXEC, BPRM_CHECK);
-	if (ret)
-		return ret;
+	return process_measurement(bprm->file, current_cred(),
+				   &prop, NULL, 0, MAY_EXEC, BPRM_CHECK, 0);
+}
 
-	security_cred_getlsmprop(bprm->cred, &prop);
-	return process_measurement(bprm->file, bprm->cred, &prop, NULL, 0,
-				   MAY_EXEC, CREDS_CHECK);
+/**
+ * ima_creds_check - based on policy, collect/store measurement.
+ * @bprm: contains the linux_binprm structure
+ * @file: contains the file descriptor of the binary being executed
+ *
+ * The OS protects against an executable file, already open for write,
+ * from being executed in deny_write_access() and an executable file,
+ * already open for execute, from being modified in get_write_access().
+ * So we can be certain that what we verify and measure here is actually
+ * what is being executed.
+ *
+ * The difference from ima_bprm_check() is that ima_creds_check() is invoked
+ * only after determining the final binary to be executed without interpreter,
+ * and not when searching for intermediate binaries. The reason is that since
+ * commit 56305aa9b6fab ("exec: Compute file based creds only once"), the
+ * credentials to be applied to the process are calculated only at that stage
+ * (bprm_creds_from_file security hook instead of bprm_check_security).
+ *
+ * On success return 0.  On integrity appraisal error, assuming the file
+ * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
+ */
+static int ima_creds_check(struct linux_binprm *bprm, const struct file *file)
+{
+	struct lsm_prop prop;
+
+	security_current_getlsmprop_subj(&prop);
+	return process_measurement((struct file *)file, bprm->cred, &prop, NULL,
+				   0, MAY_EXEC, CREDS_CHECK, 0);
 }
 
 /**
@@ -632,7 +662,7 @@ static int ima_file_check(struct file *file, int mask)
 	security_current_getlsmprop_subj(&prop);
 	return process_measurement(file, current_cred(), &prop, NULL, 0,
 				   mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
-					   MAY_APPEND), FILE_CHECK);
+					   MAY_APPEND), FILE_CHECK, 0);
 }
 
 static int __ima_inode_hash(struct inode *inode, struct file *file, char *buf,
@@ -851,12 +881,13 @@ static int ima_read_file(struct file *file, enum kernel_read_file_id read_id,
 	func = read_idmap[read_id] ?: FILE_CHECK;
 	security_current_getlsmprop_subj(&prop);
 	return process_measurement(file, current_cred(), &prop, NULL, 0,
-				   MAY_READ, func);
+				   MAY_READ, func, 0);
 }
 
 const int read_idmap[READING_MAX_ID] = {
 	[READING_FIRMWARE] = FIRMWARE_CHECK,
 	[READING_MODULE] = MODULE_CHECK,
+	[READING_MODULE_COMPRESSED] = MODULE_CHECK,
 	[READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK,
 	[READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,
 	[READING_POLICY] = POLICY_CHECK
@@ -894,7 +925,7 @@ static int ima_post_read_file(struct file *file, char *buf, loff_t size,
 	func = read_idmap[read_id] ?: FILE_CHECK;
 	security_current_getlsmprop_subj(&prop);
 	return process_measurement(file, current_cred(), &prop, buf, size,
-				   MAY_READ, func);
+				   MAY_READ, func, read_id);
 }
 
 /**
@@ -1242,6 +1273,7 @@ static int __init init_ima(void)
 static struct security_hook_list ima_hooks[] __ro_after_init = {
 	LSM_HOOK_INIT(bprm_check_security, ima_bprm_check),
 	LSM_HOOK_INIT(bprm_creds_for_exec, ima_bprm_creds_for_exec),
+	LSM_HOOK_INIT(bprm_creds_from_file, ima_creds_check),
 	LSM_HOOK_INIT(file_post_open, ima_file_check),
 	LSM_HOOK_INIT(inode_post_create_tmpfile, ima_post_create_tmpfile),
 	LSM_HOOK_INIT(file_release, ima_file_free),

security/integrity/ima/ima_policy.c

@@ -38,6 +38,7 @@
 #define IMA_GID		0x2000
 #define IMA_EGID	0x4000
 #define IMA_FGROUP	0x8000
+#define IMA_FS_SUBTYPE	0x10000
 
 #define UNKNOWN		0
 #define MEASURE		0x0001	/* same as IMA_MEASURE */
@@ -45,6 +46,7 @@
 #define APPRAISE	0x0004	/* same as IMA_APPRAISE */
 #define DONT_APPRAISE	0x0008
 #define AUDIT		0x0040
+#define DONT_AUDIT	0x0080
 #define HASH		0x0100
 #define DONT_HASH	0x0200
 
@@ -119,6 +121,7 @@ struct ima_rule_entry {
 		int type;	/* audit type */
 	} lsm[MAX_LSM_RULES];
 	char *fsname;
+	char *fs_subtype;
 	struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */
 	struct ima_rule_opt_list *label; /* Measure data grouped under this label */
 	struct ima_template_desc *template;
@@ -241,7 +244,8 @@ static struct ima_rule_entry build_appraise_rules[] __ro_after_init = {
 
 static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
 	{.action = APPRAISE, .func = MODULE_CHECK,
-	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED |
+		  IMA_CHECK_BLACKLIST},
 	{.action = APPRAISE, .func = FIRMWARE_CHECK,
 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 	{.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
@@ -397,6 +401,7 @@ static void ima_free_rule(struct ima_rule_entry *entry)
 	 * the defined_templates list and cannot be freed here
 	 */
 	kfree(entry->fsname);
+	kfree(entry->fs_subtype);
 	ima_free_rule_opt_list(entry->keyrings);
 	ima_lsm_free_rule(entry);
 	kfree(entry);
@@ -601,6 +606,12 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
 	if ((rule->flags & IMA_FSNAME)
 	    && strcmp(rule->fsname, inode->i_sb->s_type->name))
 		return false;
+	if (rule->flags & IMA_FS_SUBTYPE) {
+		if (!inode->i_sb->s_subtype)
+			return false;
+		if (strcmp(rule->fs_subtype, inode->i_sb->s_subtype))
+			return false;
+	}
 	if ((rule->flags & IMA_FSUUID) &&
 	    !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
 		return false;
@@ -674,7 +685,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
 				goto retry;
 			}
 		}
-		if (!rc) {
+		if (rc <= 0) {
 			result = false;
 			goto out;
 		}
@@ -1064,10 +1075,10 @@ void ima_update_policy(void)
 enum policy_opt {
 	Opt_measure, Opt_dont_measure,
 	Opt_appraise, Opt_dont_appraise,
-	Opt_audit, Opt_hash, Opt_dont_hash,
+	Opt_audit, Opt_dont_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_fsuuid,
+	Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname, Opt_fs_subtype, Opt_fsuuid,
 	Opt_uid_eq, Opt_euid_eq, Opt_gid_eq, Opt_egid_eq,
 	Opt_fowner_eq, Opt_fgroup_eq,
 	Opt_uid_gt, Opt_euid_gt, Opt_gid_gt, Opt_egid_gt,
@@ -1086,6 +1097,7 @@ static const match_table_t policy_tokens = {
 	{Opt_appraise, "appraise"},
 	{Opt_dont_appraise, "dont_appraise"},
 	{Opt_audit, "audit"},
+	{Opt_dont_audit, "dont_audit"},
 	{Opt_hash, "hash"},
 	{Opt_dont_hash, "dont_hash"},
 	{Opt_obj_user, "obj_user=%s"},
@@ -1098,6 +1110,7 @@ static const match_table_t policy_tokens = {
 	{Opt_mask, "mask=%s"},
 	{Opt_fsmagic, "fsmagic=%s"},
 	{Opt_fsname, "fsname=%s"},
+	{Opt_fs_subtype, "fs_subtype=%s"},
 	{Opt_fsuuid, "fsuuid=%s"},
 	{Opt_uid_eq, "uid=%s"},
 	{Opt_euid_eq, "euid=%s"},
@@ -1282,7 +1295,8 @@ static bool ima_validate_rule(struct ima_rule_entry *entry)
 		if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
 				     IMA_UID | IMA_FOWNER | IMA_FSUUID |
 				     IMA_INMASK | IMA_EUID | IMA_PCR |
-				     IMA_FSNAME | IMA_GID | IMA_EGID |
+				     IMA_FSNAME | IMA_FS_SUBTYPE |
+				     IMA_GID | IMA_EGID |
 				     IMA_FGROUP | IMA_DIGSIG_REQUIRED |
 				     IMA_PERMIT_DIRECTIO | IMA_VALIDATE_ALGOS |
 				     IMA_CHECK_BLACKLIST | IMA_VERITY_REQUIRED))
@@ -1295,7 +1309,8 @@ static bool ima_validate_rule(struct ima_rule_entry *entry)
 		if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
 				     IMA_UID | IMA_FOWNER | IMA_FSUUID |
 				     IMA_INMASK | IMA_EUID | IMA_PCR |
-				     IMA_FSNAME | IMA_GID | IMA_EGID |
+				     IMA_FSNAME | IMA_FS_SUBTYPE |
+				     IMA_GID | IMA_EGID |
 				     IMA_FGROUP | IMA_DIGSIG_REQUIRED |
 				     IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
 				     IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
@@ -1308,7 +1323,8 @@ static bool ima_validate_rule(struct ima_rule_entry *entry)
 
 		if (entry->flags & ~(IMA_FUNC | IMA_FSMAGIC | IMA_UID |
 				     IMA_FOWNER | IMA_FSUUID | IMA_EUID |
-				     IMA_PCR | IMA_FSNAME | IMA_GID | IMA_EGID |
+				     IMA_PCR | IMA_FSNAME | IMA_FS_SUBTYPE |
+				     IMA_GID | IMA_EGID |
 				     IMA_FGROUP))
 			return false;
 
@@ -1478,6 +1494,14 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 
 			entry->action = AUDIT;
 			break;
+		case Opt_dont_audit:
+			ima_log_string(ab, "action", "dont_audit");
+
+			if (entry->action != UNKNOWN)
+				result = -EINVAL;
+
+			entry->action = DONT_AUDIT;
+			break;
 		case Opt_hash:
 			ima_log_string(ab, "action", "hash");
 
@@ -1587,6 +1611,22 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 			result = 0;
 			entry->flags |= IMA_FSNAME;
 			break;
+		case Opt_fs_subtype:
+			ima_log_string(ab, "fs_subtype", args[0].from);
+
+			if (entry->fs_subtype) {
+				result = -EINVAL;
+				break;
+			}
+
+			entry->fs_subtype = kstrdup(args[0].from, GFP_KERNEL);
+			if (!entry->fs_subtype) {
+				result = -ENOMEM;
+				break;
+			}
+			result = 0;
+			entry->flags |= IMA_FS_SUBTYPE;
+			break;
 		case Opt_keyrings:
 			ima_log_string(ab, "keyrings", args[0].from);
 
@@ -2097,6 +2137,8 @@ int ima_policy_show(struct seq_file *m, void *v)
 		seq_puts(m, pt(Opt_dont_appraise));
 	if (entry->action & AUDIT)
 		seq_puts(m, pt(Opt_audit));
+	if (entry->action & DONT_AUDIT)
+		seq_puts(m, pt(Opt_dont_audit));
 	if (entry->action & HASH)
 		seq_puts(m, pt(Opt_hash));
 	if (entry->action & DONT_HASH)
@@ -2133,6 +2175,12 @@ int ima_policy_show(struct seq_file *m, void *v)
 		seq_puts(m, " ");
 	}
 
+	if (entry->flags & IMA_FS_SUBTYPE) {
+		snprintf(tbuf, sizeof(tbuf), "%s", entry->fs_subtype);
+		seq_printf(m, pt(Opt_fs_subtype), tbuf);
+		seq_puts(m, " ");
+	}
+
 	if (entry->flags & IMA_KEYRINGS) {
 		seq_puts(m, "keyrings=");
 		ima_show_rule_opt_list(m, entry->keyrings);

security/ipe/hooks.c

@@ -118,6 +118,7 @@ int ipe_kernel_read_file(struct file *file, enum kernel_read_file_id id,
 		op = IPE_OP_FIRMWARE;
 		break;
 	case READING_MODULE:
+	case READING_MODULE_COMPRESSED:
 		op = IPE_OP_KERNEL_MODULE;
 		break;
 	case READING_KEXEC_INITRAMFS:

security/selinux/hooks.c

@@ -4296,7 +4296,7 @@ static int selinux_kernel_read_file(struct file *file,
 {
 	int rc = 0;
 
-	BUILD_BUG_ON_MSG(READING_MAX_ID > 7,
+	BUILD_BUG_ON_MSG(READING_MAX_ID > 8,
 			 "New kernel_read_file_id introduced; update SELinux!");
 
 	switch (id) {
@@ -4304,6 +4304,7 @@ static int selinux_kernel_read_file(struct file *file,
 		rc = selinux_kernel_load_from_file(file, SYSTEM__FIRMWARE_LOAD);
 		break;
 	case READING_MODULE:
+	case READING_MODULE_COMPRESSED:
 		rc = selinux_kernel_load_from_file(file, SYSTEM__MODULE_LOAD);
 		break;
 	case READING_KEXEC_IMAGE:
@@ -4332,7 +4333,7 @@ static int selinux_kernel_load_data(enum kernel_load_data_id id, bool contents)
 {
 	int rc = 0;
 
-	BUILD_BUG_ON_MSG(LOADING_MAX_ID > 7,
+	BUILD_BUG_ON_MSG(LOADING_MAX_ID > 8,
 			 "New kernel_load_data_id introduced; update SELinux!");
 
 	switch (id) {