diff mbox series

[v11,23/27] ima: Introduce securityfs file to activate an IMA namespace

Message ID 20220302134703.1273041-24-stefanb@linux.ibm.com (mailing list archive)
State New, archived
Headers show
Series ima: Namespace IMA with audit support in IMA-ns | expand

Commit Message

Stefan Berger March 2, 2022, 1:46 p.m. UTC
Introduce the IMA securityfs file 'active' that users now need to
write a "1" into (precisely a '1\0' or '1\n') to activate an IMA namespace.
When reading from the file, it shows either '0' or '1'.

The rationale for introducing a file to activate an IMA namespace is that
subsequent support for IMA-measurement and IMA-appraisal will add
configuration files for selecting for example the template that an IMA
namespace is supposed to use for logging measurements, which will add
an IMA namespace configuration stage (using securityfs files) before its
activation. Besides that it allows to create a user namespace with
securityfs mounted and an inactive IMA namespace.

Also, introduce ns_is_active() to be used in those places where the
ima_namespace pointer may either be NULL or where the active flag may not
have been set, yet. An inactive IMA namespace should never be accessed
since it has not been initialized, yet.

Set the init_ima_ns's active flag since it is considered active right from
the beginning.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>

---
v11:
 - Move code from ima_fs_add_ns_files() into ima_fs_ns_init()
 - Use ima_ns_flags and IMA_NS_ACTIVE instead of 'atomic_t active'

v10:
 - use memdup_user_nul to copy input from user
 - propagating error returned from ima_fs_add_ns_files()
---
 security/integrity/ima/ima.h             |  6 +++
 security/integrity/ima/ima_fs.c          | 62 ++++++++++++++++++++++++
 security/integrity/ima/ima_init_ima_ns.c |  1 +
 security/integrity/ima/ima_main.c        |  2 +-
 4 files changed, 70 insertions(+), 1 deletion(-)

Comments

kernel test robot March 2, 2022, 7:16 p.m. UTC | #1
Hi Stefan,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.17-rc6]
[cannot apply to zohar-integrity/next-integrity linux/master jmorris-security/next-testing next-20220302]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Stefan-Berger/ima-Namespace-IMA-with-audit-support-in-IMA-ns/20220302-215707
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git fb184c4af9b9f4563e7a126219389986a71d5b5b
config: arm64-randconfig-r006-20220302 (https://download.01.org/0day-ci/archive/20220303/202203030340.kolQS5ma-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project d271fc04d5b97b12e6b797c6067d3c96a8d7470e)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm64 cross compiling tool for clang build
        # apt-get install binutils-aarch64-linux-gnu
        # https://github.com/0day-ci/linux/commit/59a9ba1130510d6693a61c6eb84c29983fa696df
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Stefan-Berger/ima-Namespace-IMA-with-audit-support-in-IMA-ns/20220302-215707
        git checkout 59a9ba1130510d6693a61c6eb84c29983fa696df
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash security/integrity/ima/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> security/integrity/ima/ima_fs.c:591:3: warning: variable 'ret' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
                   if (IS_ERR(active))
                   ^~~~~~~~~~~~~~~~~~~
   include/linux/compiler.h:56:28: note: expanded from macro 'if'
   #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/compiler.h:58:30: note: expanded from macro '__trace_if_var'
   #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   security/integrity/ima/ima_fs.c:608:9: note: uninitialized use occurs here
           return ret;
                  ^~~
   security/integrity/ima/ima_fs.c:591:3: note: remove the 'if' if its condition is always false
                   if (IS_ERR(active))
                   ^~~~~~~~~~~~~~~~~~~
   include/linux/compiler.h:56:23: note: expanded from macro 'if'
   #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
                         ^
   security/integrity/ima/ima_fs.c:516:9: note: initialize the variable 'ret' to silence this warning
           int ret;
                  ^
                   = 0
   1 warning generated.


vim +591 security/integrity/ima/ima_fs.c

   504	
   505	int ima_fs_ns_init(struct user_namespace *user_ns, struct dentry *root)
   506	{
   507		struct ima_namespace *ns = ima_ns_from_user_ns(user_ns);
   508		struct dentry *int_dir;
   509		struct dentry *ima_dir = NULL;
   510		struct dentry *ima_symlink = NULL;
   511		struct dentry *binary_runtime_measurements = NULL;
   512		struct dentry *ascii_runtime_measurements = NULL;
   513		struct dentry *runtime_measurements_count = NULL;
   514		struct dentry *violations = NULL;
   515		struct dentry *active = NULL;
   516		int ret;
   517	
   518		/* FIXME: update when evm and integrity are namespaced */
   519		if (user_ns != &init_user_ns) {
   520			int_dir = securityfs_create_dir("integrity", root);
   521			if (IS_ERR(int_dir))
   522				return PTR_ERR(int_dir);
   523		} else {
   524			int_dir = integrity_dir;
   525		}
   526	
   527		ima_dir = securityfs_create_dir("ima", int_dir);
   528		if (IS_ERR(ima_dir)) {
   529			ret = PTR_ERR(ima_dir);
   530			goto out;
   531		}
   532	
   533		ima_symlink = securityfs_create_symlink("ima", root, "integrity/ima",
   534							NULL);
   535		if (IS_ERR(ima_symlink)) {
   536			ret = PTR_ERR(ima_symlink);
   537			goto out;
   538		}
   539	
   540		binary_runtime_measurements =
   541		    securityfs_create_file("binary_runtime_measurements",
   542					   S_IRUSR | S_IRGRP, ima_dir, NULL,
   543					   &ima_measurements_ops);
   544		if (IS_ERR(binary_runtime_measurements)) {
   545			ret = PTR_ERR(binary_runtime_measurements);
   546			goto out;
   547		}
   548	
   549		ascii_runtime_measurements =
   550		    securityfs_create_file("ascii_runtime_measurements",
   551					   S_IRUSR | S_IRGRP, ima_dir, NULL,
   552					   &ima_ascii_measurements_ops);
   553		if (IS_ERR(ascii_runtime_measurements)) {
   554			ret = PTR_ERR(ascii_runtime_measurements);
   555			goto out;
   556		}
   557	
   558		runtime_measurements_count =
   559		    securityfs_create_file("runtime_measurements_count",
   560					   S_IRUSR | S_IRGRP, ima_dir, NULL,
   561					   &ima_measurements_count_ops);
   562		if (IS_ERR(runtime_measurements_count)) {
   563			ret = PTR_ERR(runtime_measurements_count);
   564			goto out;
   565		}
   566	
   567		violations =
   568		    securityfs_create_file("violations", S_IRUSR | S_IRGRP,
   569					   ima_dir, NULL, &ima_htable_violations_ops);
   570		if (IS_ERR(violations)) {
   571			ret = PTR_ERR(violations);
   572			goto out;
   573		}
   574	
   575		if (!ns->ima_policy_removed) {
   576			ns->ima_policy =
   577			    securityfs_create_file("policy", POLICY_FILE_FLAGS,
   578						   ima_dir, NULL,
   579						   &ima_measure_policy_ops);
   580			if (IS_ERR(ns->ima_policy)) {
   581				ret = PTR_ERR(ns->ima_policy);
   582				goto out;
   583			}
   584		}
   585	
   586		if (ns != &init_ima_ns) {
   587			active =
   588			    securityfs_create_file("active",
   589						   S_IRUSR | S_IWUSR | S_IRGRP, ima_dir,
   590						   NULL, &ima_active_ops);
 > 591			if (IS_ERR(active))
   592				goto out;
   593		}
   594	
   595		return 0;
   596	out:
   597		securityfs_remove(active);
   598		securityfs_remove(ns->ima_policy);
   599		securityfs_remove(violations);
   600		securityfs_remove(runtime_measurements_count);
   601		securityfs_remove(ascii_runtime_measurements);
   602		securityfs_remove(binary_runtime_measurements);
   603		securityfs_remove(ima_symlink);
   604		securityfs_remove(ima_dir);
   605		if (user_ns != &init_user_ns)
   606			securityfs_remove(int_dir);
   607	
   608		return ret;
   609	}
   610	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 801dc3c8bfde..2cc286f9e839 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -126,6 +126,7 @@  struct ima_namespace {
 	unsigned long ima_ns_flags;
 /* Bit numbers for above flags; use BIT() to get flag */
 #define IMA_NS_LSM_UPDATE_RULES		0
+#define IMA_NS_ACTIVE			1
 
 	struct rb_root ns_status_tree;
 	rwlock_t ns_tree_lock;
@@ -158,6 +159,11 @@  struct ima_namespace {
 } __randomize_layout;
 extern struct ima_namespace init_ima_ns;
 
+static inline bool ns_is_active(struct ima_namespace *ns)
+{
+	return (ns && test_bit(IMA_NS_ACTIVE, &ns->ima_ns_flags));
+}
+
 extern const int read_idmap[];
 
 #ifdef CONFIG_HAVE_IMA_KEXEC
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 84cd02a9e19b..8254c4e683d5 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -451,6 +451,57 @@  static const struct file_operations ima_measure_policy_ops = {
 	.llseek = generic_file_llseek,
 };
 
+static ssize_t ima_show_active(struct file *filp,
+			       char __user *buf,
+			       size_t count, loff_t *ppos)
+{
+	struct ima_namespace *ns = &init_ima_ns;
+	char tmpbuf[2];
+	ssize_t len;
+
+	len = scnprintf(tmpbuf, sizeof(tmpbuf),
+			"%d\n", !!test_bit(IMA_NS_ACTIVE, &ns->ima_ns_flags));
+	return simple_read_from_buffer(buf, count, ppos, tmpbuf, len);
+}
+
+static ssize_t ima_write_active(struct file *filp,
+				const char __user *buf,
+				size_t count, loff_t *ppos)
+{
+	struct ima_namespace *ns = &init_ima_ns;
+	unsigned int active;
+	char *kbuf;
+	int err;
+
+	if (ns_is_active(ns))
+		return -EBUSY;
+
+	/* accepting '1\n' and '1\0' and no partial writes */
+	if (count >= 3 || *ppos != 0)
+		return -EINVAL;
+
+	kbuf = memdup_user_nul(buf, count);
+	if (IS_ERR(kbuf))
+		return PTR_ERR(kbuf);
+
+	err = kstrtouint(kbuf, 10, &active);
+	kfree(kbuf);
+	if (err)
+		return err;
+
+	if (active != 1)
+		return -EINVAL;
+
+	set_bit(IMA_NS_ACTIVE, &ns->ima_ns_flags);
+
+	return count;
+}
+
+static const struct file_operations ima_active_ops = {
+	.read = ima_show_active,
+	.write = ima_write_active,
+};
+
 int ima_fs_ns_init(struct user_namespace *user_ns, struct dentry *root)
 {
 	struct ima_namespace *ns = ima_ns_from_user_ns(user_ns);
@@ -461,6 +512,7 @@  int ima_fs_ns_init(struct user_namespace *user_ns, struct dentry *root)
 	struct dentry *ascii_runtime_measurements = NULL;
 	struct dentry *runtime_measurements_count = NULL;
 	struct dentry *violations = NULL;
+	struct dentry *active = NULL;
 	int ret;
 
 	/* FIXME: update when evm and integrity are namespaced */
@@ -531,8 +583,18 @@  int ima_fs_ns_init(struct user_namespace *user_ns, struct dentry *root)
 		}
 	}
 
+	if (ns != &init_ima_ns) {
+		active =
+		    securityfs_create_file("active",
+					   S_IRUSR | S_IWUSR | S_IRGRP, ima_dir,
+					   NULL, &ima_active_ops);
+		if (IS_ERR(active))
+			goto out;
+	}
+
 	return 0;
 out:
+	securityfs_remove(active);
 	securityfs_remove(ns->ima_policy);
 	securityfs_remove(violations);
 	securityfs_remove(runtime_measurements_count);
diff --git a/security/integrity/ima/ima_init_ima_ns.c b/security/integrity/ima/ima_init_ima_ns.c
index 41e7db0c9749..5c57abfc70ea 100644
--- a/security/integrity/ima/ima_init_ima_ns.c
+++ b/security/integrity/ima/ima_init_ima_ns.c
@@ -58,5 +58,6 @@  struct ima_namespace init_ima_ns = {
 	.ima_lsm_policy_notifier = {
 		.notifier_call = ima_lsm_policy_change,
 	},
+	.ima_ns_flags = BIT(IMA_NS_ACTIVE),
 };
 EXPORT_SYMBOL(init_ima_ns);
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 720b51180b00..fa12080b8b94 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -441,7 +441,7 @@  static int process_measurement(struct user_namespace *user_ns,
 
 	while (user_ns) {
 		ns = ima_ns_from_user_ns(user_ns);
-		if (ns) {
+		if (ns_is_active(ns)) {
 			int rc;
 
 			rc = __process_measurement(ns, file, cred, secid, buf,