Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull integrity updates from James Morris:
 "From Mimi: This contains a couple of bug fixes, including one for a
  recent problem with calculating file hashes on overlayfs, and some
  code cleanup"

* 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  MAINTAINERS: add Jarkko as maintainer for trusted keys
  ima: open a new file instance if no read permissions
  ima: fix showing large 'violations' or 'runtime_measurements_count'
  security/integrity: remove unnecessary 'init_keyring' variable
  security/integrity: constify some read-only data
  vfs: require i_size <= SIZE_MAX in kernel_read_file()

MAINTAINERS

@@ -8165,6 +8165,7 @@ F:	security/keys/encrypted-keys/
 
 KEYS-TRUSTED
 M:	James Bottomley <jejb@linux.vnet.ibm.com>
+M:      Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
 M:	Mimi Zohar <zohar@linux.vnet.ibm.com>
 L:	linux-integrity@vger.kernel.org
 L:	keyrings@vger.kernel.org

fs/exec.c

@@ -908,14 +908,14 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
 		goto out;
 
 	i_size = i_size_read(file_inode(file));
-	if (max_size > 0 && i_size > max_size) {
-		ret = -EFBIG;
-		goto out;
-	}
 	if (i_size <= 0) {
 		ret = -EINVAL;
 		goto out;
 	}
+	if (i_size > SIZE_MAX || (max_size > 0 && i_size > max_size)) {
+		ret = -EFBIG;
+		goto out;
+	}
 
 	if (id != READING_FIRMWARE_PREALLOC_BUFFER)
 		*buf = vmalloc(i_size);

security/integrity/digsig.c

@@ -26,7 +26,7 @@
 
 static struct key *keyring[INTEGRITY_KEYRING_MAX];
 
-static const char *keyring_name[INTEGRITY_KEYRING_MAX] = {
+static const char * const keyring_name[INTEGRITY_KEYRING_MAX] = {
 #ifndef CONFIG_INTEGRITY_TRUSTED_KEYRING
 	"_evm",
 	"_ima",
@@ -37,12 +37,6 @@ static const char *keyring_name[INTEGRITY_KEYRING_MAX] = {
 	"_module",
 };
 
-#ifdef CONFIG_INTEGRITY_TRUSTED_KEYRING
-static bool init_keyring __initdata = true;
-#else
-static bool init_keyring __initdata;
-#endif
-
 #ifdef CONFIG_IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY
 #define restrict_link_to_ima restrict_link_by_builtin_and_secondary_trusted
 #else
@@ -85,7 +79,7 @@ int __init integrity_init_keyring(const unsigned int id)
 	struct key_restriction *restriction;
 	int err = 0;
 
-	if (!init_keyring)
+	if (!IS_ENABLED(CONFIG_INTEGRITY_TRUSTED_KEYRING))
 		return 0;
 
 	restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);

security/integrity/evm/evm_crypto.c

@@ -27,7 +27,7 @@
 #define EVMKEY "evm-key"
 #define MAX_KEY_SIZE 128
 static unsigned char evmkey[MAX_KEY_SIZE];
-static int evmkey_len = MAX_KEY_SIZE;
+static const int evmkey_len = MAX_KEY_SIZE;
 
 struct crypto_shash *hmac_tfm;
 static struct crypto_shash *evm_tfm[HASH_ALGO__LAST];
@@ -38,7 +38,7 @@ static DEFINE_MUTEX(mutex);
 
 static unsigned long evm_set_key_flags;
 
-static char * const evm_hmac = "hmac(sha1)";
+static const char evm_hmac[] = "hmac(sha1)";
 
 /**
  * evm_set_key() - set EVM HMAC key from the kernel

security/integrity/ima/ima.h

@@ -88,7 +88,7 @@ struct ima_template_desc {
 	char *name;
 	char *fmt;
 	int num_fields;
-	struct ima_template_field **fields;
+	const struct ima_template_field **fields;
 };
 
 struct ima_template_entry {

security/integrity/ima/ima_api.c

@@ -51,7 +51,8 @@ int ima_alloc_init_template(struct ima_event_data *event_data,
 
 	(*entry)->template_desc = template_desc;
 	for (i = 0; i < template_desc->num_fields; i++) {
-		struct ima_template_field *field = template_desc->fields[i];
+		const struct ima_template_field *field =
+			template_desc->fields[i];
 		u32 len;
 
 		result = field->field_init(event_data,

security/integrity/ima/ima_crypto.c

@@ -210,7 +210,7 @@ static int ima_calc_file_hash_atfm(struct file *file,
 {
 	loff_t i_size, offset;
 	char *rbuf[2] = { NULL, };
-	int rc, read = 0, rbuf_len, active = 0, ahash_rc = 0;
+	int rc, rbuf_len, active = 0, ahash_rc = 0;
 	struct ahash_request *req;
 	struct scatterlist sg[1];
 	struct crypto_wait wait;
@@ -257,11 +257,6 @@ static int ima_calc_file_hash_atfm(struct file *file,
 					  &rbuf_size[1], 0);
 	}
 
-	if (!(file->f_mode & FMODE_READ)) {
-		file->f_mode |= FMODE_READ;
-		read = 1;
-	}
-
 	for (offset = 0; offset < i_size; offset += rbuf_len) {
 		if (!rbuf[1] && offset) {
 			/* Not using two buffers, and it is not the first
@@ -300,8 +295,6 @@ static int ima_calc_file_hash_atfm(struct file *file,
 	/* wait for the last update request to complete */
 	rc = ahash_wait(ahash_rc, &wait);
 out3:
-	if (read)
-		file->f_mode &= ~FMODE_READ;
 	ima_free_pages(rbuf[0], rbuf_size[0]);
 	ima_free_pages(rbuf[1], rbuf_size[1]);
 out2:
@@ -336,7 +329,7 @@ static int ima_calc_file_hash_tfm(struct file *file,
 {
 	loff_t i_size, offset = 0;
 	char *rbuf;
-	int rc, read = 0;
+	int rc;
 	SHASH_DESC_ON_STACK(shash, tfm);
 
 	shash->tfm = tfm;
@@ -357,11 +350,6 @@ static int ima_calc_file_hash_tfm(struct file *file,
 	if (!rbuf)
 		return -ENOMEM;
 
-	if (!(file->f_mode & FMODE_READ)) {
-		file->f_mode |= FMODE_READ;
-		read = 1;
-	}
-
 	while (offset < i_size) {
 		int rbuf_len;
 
@@ -378,8 +366,6 @@ static int ima_calc_file_hash_tfm(struct file *file,
 		if (rc)
 			break;
 	}
-	if (read)
-		file->f_mode &= ~FMODE_READ;
 	kfree(rbuf);
 out:
 	if (!rc)
@@ -420,6 +406,8 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
 {
 	loff_t i_size;
 	int rc;
+	struct file *f = file;
+	bool new_file_instance = false, modified_flags = false;
 
 	/*
 	 * For consistency, fail file's opened with the O_DIRECT flag on
@@ -431,15 +419,41 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
 		return -EINVAL;
 	}
 
-	i_size = i_size_read(file_inode(file));
-
-	if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
-		rc = ima_calc_file_ahash(file, hash);
-		if (!rc)
-			return 0;
+	/* Open a new file instance in O_RDONLY if we cannot read */
+	if (!(file->f_mode & FMODE_READ)) {
+		int flags = file->f_flags & ~(O_WRONLY | O_APPEND |
+				O_TRUNC | O_CREAT | O_NOCTTY | O_EXCL);
+		flags |= O_RDONLY;
+		f = dentry_open(&file->f_path, flags, file->f_cred);
+		if (IS_ERR(f)) {
+			/*
+			 * Cannot open the file again, lets modify f_flags
+			 * of original and continue
+			 */
+			pr_info_ratelimited("Unable to reopen file for reading.\n");
+			f = file;
+			f->f_flags |= FMODE_READ;
+			modified_flags = true;
+		} else {
+			new_file_instance = true;
+		}
 	}
 
-	return ima_calc_file_shash(file, hash);
+	i_size = i_size_read(file_inode(f));
+
+	if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
+		rc = ima_calc_file_ahash(f, hash);
+		if (!rc)
+			goto out;
+	}
+
+	rc = ima_calc_file_shash(f, hash);
+out:
+	if (new_file_instance)
+		fput(f);
+	else if (modified_flags)
+		f->f_flags &= ~FMODE_READ;
+	return rc;
 }
 
 /*

security/integrity/ima/ima_fs.c

@@ -42,14 +42,14 @@ static int __init default_canonical_fmt_setup(char *str)
 __setup("ima_canonical_fmt", default_canonical_fmt_setup);
 
 static int valid_policy = 1;
-#define TMPBUFLEN 12
+
 static ssize_t ima_show_htable_value(char __user *buf, size_t count,
 				     loff_t *ppos, atomic_long_t *val)
 {
-	char tmpbuf[TMPBUFLEN];
+	char tmpbuf[32];	/* greater than largest 'long' string value */
 	ssize_t len;
 
-	len = scnprintf(tmpbuf, TMPBUFLEN, "%li\n", atomic_long_read(val));
+	len = scnprintf(tmpbuf, sizeof(tmpbuf), "%li\n", atomic_long_read(val));
 	return simple_read_from_buffer(buf, count, ppos, tmpbuf, len);
 }
 
@@ -179,7 +179,8 @@ int ima_measurements_show(struct seq_file *m, void *v)
 	/* 6th:  template specific data */
 	for (i = 0; i < e->template_desc->num_fields; i++) {
 		enum ima_show_type show = IMA_SHOW_BINARY;
-		struct ima_template_field *field = e->template_desc->fields[i];
+		const struct ima_template_field *field =
+			e->template_desc->fields[i];
 
 		if (is_ima_template && strcmp(field->field_id, "d") == 0)
 			show = IMA_SHOW_BINARY_NO_FIELD_LEN;

security/integrity/ima/ima_init.c

@@ -25,7 +25,7 @@
 #include "ima.h"
 
 /* name for boot aggregate entry */
-static const char *boot_aggregate_name = "boot_aggregate";
+static const char boot_aggregate_name[] = "boot_aggregate";
 struct tpm_chip *ima_tpm_chip;
 
 /* Add the boot aggregate to the IMA measurement list and extend

security/integrity/ima/ima_main.c

@@ -440,7 +440,7 @@ int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
 	return 0;
 }
 
-static int read_idmap[READING_MAX_ID] = {
+static const int read_idmap[READING_MAX_ID] = {
 	[READING_FIRMWARE] = FIRMWARE_CHECK,
 	[READING_FIRMWARE_PREALLOC_BUFFER] = FIRMWARE_CHECK,
 	[READING_MODULE] = MODULE_CHECK,

security/integrity/ima/ima_template.c

@@ -32,7 +32,7 @@ static struct ima_template_desc builtin_templates[] = {
 static LIST_HEAD(defined_templates);
 static DEFINE_SPINLOCK(template_list);
 
-static struct ima_template_field supported_fields[] = {
+static const struct ima_template_field supported_fields[] = {
 	{.field_id = "d", .field_init = ima_eventdigest_init,
 	 .field_show = ima_show_template_digest},
 	{.field_id = "n", .field_init = ima_eventname_init,
@@ -49,7 +49,7 @@ static struct ima_template_field supported_fields[] = {
 static struct ima_template_desc *ima_template;
 static struct ima_template_desc *lookup_template_desc(const char *name);
 static int template_desc_init_fields(const char *template_fmt,
-				     struct ima_template_field ***fields,
+				     const struct ima_template_field ***fields,
 				     int *num_fields);
 
 static int __init ima_template_setup(char *str)
@@ -125,7 +125,8 @@ static struct ima_template_desc *lookup_template_desc(const char *name)
 	return found ? template_desc : NULL;
 }
 
-static struct ima_template_field *lookup_template_field(const char *field_id)
+static const struct ima_template_field *
+lookup_template_field(const char *field_id)
 {
 	int i;
 
@@ -153,11 +154,11 @@ static int template_fmt_size(const char *template_fmt)
 }
 
 static int template_desc_init_fields(const char *template_fmt,
-				     struct ima_template_field ***fields,
+				     const struct ima_template_field ***fields,
 				     int *num_fields)
 {
 	const char *template_fmt_ptr;
-	struct ima_template_field *found_fields[IMA_TEMPLATE_NUM_FIELDS_MAX];
+	const struct ima_template_field *found_fields[IMA_TEMPLATE_NUM_FIELDS_MAX];
 	int template_num_fields;
 	int i, len;