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authorLinus Torvalds <torvalds@linux-foundation.org>2013-11-22 07:46:00 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2013-11-22 07:46:00 +0400
commit78dc53c422172a317adb0776dfb687057ffa28b7 (patch)
tree7c5d15da75d769d01f6a992c24c3490b3867d5b2 /drivers/char/tpm/tpm_i2c_atmel.c
parent3eaded86ac3e7f00fb3eeb8162d89e9a34e42fb0 (diff)
parent62fe318256befbd1b4a6765e71d9c997f768fe79 (diff)
downloadlinux-78dc53c422172a317adb0776dfb687057ffa28b7.tar.xz
Merge branch 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull security subsystem updates from James Morris: "In this patchset, we finally get an SELinux update, with Paul Moore taking over as maintainer of that code. Also a significant update for the Keys subsystem, as well as maintenance updates to Smack, IMA, TPM, and Apparmor" and since I wanted to know more about the updates to key handling, here's the explanation from David Howells on that: "Okay. There are a number of separate bits. I'll go over the big bits and the odd important other bit, most of the smaller bits are just fixes and cleanups. If you want the small bits accounting for, I can do that too. (1) Keyring capacity expansion. KEYS: Consolidate the concept of an 'index key' for key access KEYS: Introduce a search context structure KEYS: Search for auth-key by name rather than target key ID Add a generic associative array implementation. KEYS: Expand the capacity of a keyring Several of the patches are providing an expansion of the capacity of a keyring. Currently, the maximum size of a keyring payload is one page. Subtract a small header and then divide up into pointers, that only gives you ~500 pointers on an x86_64 box. However, since the NFS idmapper uses a keyring to store ID mapping data, that has proven to be insufficient to the cause. Whatever data structure I use to handle the keyring payload, it can only store pointers to keys, not the keys themselves because several keyrings may point to a single key. This precludes inserting, say, and rb_node struct into the key struct for this purpose. I could make an rbtree of records such that each record has an rb_node and a key pointer, but that would use four words of space per key stored in the keyring. It would, however, be able to use much existing code. I selected instead a non-rebalancing radix-tree type approach as that could have a better space-used/key-pointer ratio. I could have used the radix tree implementation that we already have and insert keys into it by their serial numbers, but that means any sort of search must iterate over the whole radix tree. Further, its nodes are a bit on the capacious side for what I want - especially given that key serial numbers are randomly allocated, thus leaving a lot of empty space in the tree. So what I have is an associative array that internally is a radix-tree with 16 pointers per node where the index key is constructed from the key type pointer and the key description. This means that an exact lookup by type+description is very fast as this tells us how to navigate directly to the target key. I made the data structure general in lib/assoc_array.c as far as it is concerned, its index key is just a sequence of bits that leads to a pointer. It's possible that someone else will be able to make use of it also. FS-Cache might, for example. (2) Mark keys as 'trusted' and keyrings as 'trusted only'. KEYS: verify a certificate is signed by a 'trusted' key KEYS: Make the system 'trusted' keyring viewable by userspace KEYS: Add a 'trusted' flag and a 'trusted only' flag KEYS: Separate the kernel signature checking keyring from module signing These patches allow keys carrying asymmetric public keys to be marked as being 'trusted' and allow keyrings to be marked as only permitting the addition or linkage of trusted keys. Keys loaded from hardware during kernel boot or compiled into the kernel during build are marked as being trusted automatically. New keys can be loaded at runtime with add_key(). They are checked against the system keyring contents and if their signatures can be validated with keys that are already marked trusted, then they are marked trusted also and can thus be added into the master keyring. Patches from Mimi Zohar make this usable with the IMA keyrings also. (3) Remove the date checks on the key used to validate a module signature. X.509: Remove certificate date checks It's not reasonable to reject a signature just because the key that it was generated with is no longer valid datewise - especially if the kernel hasn't yet managed to set the system clock when the first module is loaded - so just remove those checks. (4) Make it simpler to deal with additional X.509 being loaded into the kernel. KEYS: Load *.x509 files into kernel keyring KEYS: Have make canonicalise the paths of the X.509 certs better to deduplicate The builder of the kernel now just places files with the extension ".x509" into the kernel source or build trees and they're concatenated by the kernel build and stuffed into the appropriate section. (5) Add support for userspace kerberos to use keyrings. KEYS: Add per-user_namespace registers for persistent per-UID kerberos caches KEYS: Implement a big key type that can save to tmpfs Fedora went to, by default, storing kerberos tickets and tokens in tmpfs. We looked at storing it in keyrings instead as that confers certain advantages such as tickets being automatically deleted after a certain amount of time and the ability for the kernel to get at these tokens more easily. To make this work, two things were needed: (a) A way for the tickets to persist beyond the lifetime of all a user's sessions so that cron-driven processes can still use them. The problem is that a user's session keyrings are deleted when the session that spawned them logs out and the user's user keyring is deleted when the UID is deleted (typically when the last log out happens), so neither of these places is suitable. I've added a system keyring into which a 'persistent' keyring is created for each UID on request. Each time a user requests their persistent keyring, the expiry time on it is set anew. If the user doesn't ask for it for, say, three days, the keyring is automatically expired and garbage collected using the existing gc. All the kerberos tokens it held are then also gc'd. (b) A key type that can hold really big tickets (up to 1MB in size). The problem is that Active Directory can return huge tickets with lots of auxiliary data attached. We don't, however, want to eat up huge tracts of unswappable kernel space for this, so if the ticket is greater than a certain size, we create a swappable shmem file and dump the contents in there and just live with the fact we then have an inode and a dentry overhead. If the ticket is smaller than that, we slap it in a kmalloc()'d buffer" * 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (121 commits) KEYS: Fix keyring content gc scanner KEYS: Fix error handling in big_key instantiation KEYS: Fix UID check in keyctl_get_persistent() KEYS: The RSA public key algorithm needs to select MPILIB ima: define '_ima' as a builtin 'trusted' keyring ima: extend the measurement list to include the file signature kernel/system_certificate.S: use real contents instead of macro GLOBAL() KEYS: fix error return code in big_key_instantiate() KEYS: Fix keyring quota misaccounting on key replacement and unlink KEYS: Fix a race between negating a key and reading the error set KEYS: Make BIG_KEYS boolean apparmor: remove the "task" arg from may_change_ptraced_domain() apparmor: remove parent task info from audit logging apparmor: remove tsk field from the apparmor_audit_struct apparmor: fix capability to not use the current task, during reporting Smack: Ptrace access check mode ima: provide hash algo info in the xattr ima: enable support for larger default filedata hash algorithms ima: define kernel parameter 'ima_template=' to change configured default ima: add Kconfig default measurement list template ...
Diffstat (limited to 'drivers/char/tpm/tpm_i2c_atmel.c')
-rw-r--r--drivers/char/tpm/tpm_i2c_atmel.c284
1 files changed, 284 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm_i2c_atmel.c b/drivers/char/tpm/tpm_i2c_atmel.c
new file mode 100644
index 000000000000..c3cd7fe481a1
--- /dev/null
+++ b/drivers/char/tpm/tpm_i2c_atmel.c
@@ -0,0 +1,284 @@
+/*
+ * ATMEL I2C TPM AT97SC3204T
+ *
+ * Copyright (C) 2012 V Lab Technologies
+ * Teddy Reed <teddy@prosauce.org>
+ * Copyright (C) 2013, Obsidian Research Corp.
+ * Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
+ * Device driver for ATMEL I2C TPMs.
+ *
+ * Teddy Reed determined the basic I2C command flow, unlike other I2C TPM
+ * devices the raw TCG formatted TPM command data is written via I2C and then
+ * raw TCG formatted TPM command data is returned via I2C.
+ *
+ * TGC status/locality/etc functions seen in the LPC implementation do not
+ * seem to be present.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see http://www.gnu.org/licenses/>.
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include "tpm.h"
+
+#define I2C_DRIVER_NAME "tpm_i2c_atmel"
+
+#define TPM_I2C_SHORT_TIMEOUT 750 /* ms */
+#define TPM_I2C_LONG_TIMEOUT 2000 /* 2 sec */
+
+#define ATMEL_STS_OK 1
+
+struct priv_data {
+ size_t len;
+ /* This is the amount we read on the first try. 25 was chosen to fit a
+ * fair number of read responses in the buffer so a 2nd retry can be
+ * avoided in small message cases. */
+ u8 buffer[sizeof(struct tpm_output_header) + 25];
+};
+
+static int i2c_atmel_send(struct tpm_chip *chip, u8 *buf, size_t len)
+{
+ struct priv_data *priv = chip->vendor.priv;
+ struct i2c_client *client = to_i2c_client(chip->dev);
+ s32 status;
+
+ priv->len = 0;
+
+ if (len <= 2)
+ return -EIO;
+
+ status = i2c_master_send(client, buf, len);
+
+ dev_dbg(chip->dev,
+ "%s(buf=%*ph len=%0zx) -> sts=%d\n", __func__,
+ (int)min_t(size_t, 64, len), buf, len, status);
+ return status;
+}
+
+static int i2c_atmel_recv(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+ struct priv_data *priv = chip->vendor.priv;
+ struct i2c_client *client = to_i2c_client(chip->dev);
+ struct tpm_output_header *hdr =
+ (struct tpm_output_header *)priv->buffer;
+ u32 expected_len;
+ int rc;
+
+ if (priv->len == 0)
+ return -EIO;
+
+ /* Get the message size from the message header, if we didn't get the
+ * whole message in read_status then we need to re-read the
+ * message. */
+ expected_len = be32_to_cpu(hdr->length);
+ if (expected_len > count)
+ return -ENOMEM;
+
+ if (priv->len >= expected_len) {
+ dev_dbg(chip->dev,
+ "%s early(buf=%*ph count=%0zx) -> ret=%d\n", __func__,
+ (int)min_t(size_t, 64, expected_len), buf, count,
+ expected_len);
+ memcpy(buf, priv->buffer, expected_len);
+ return expected_len;
+ }
+
+ rc = i2c_master_recv(client, buf, expected_len);
+ dev_dbg(chip->dev,
+ "%s reread(buf=%*ph count=%0zx) -> ret=%d\n", __func__,
+ (int)min_t(size_t, 64, expected_len), buf, count,
+ expected_len);
+ return rc;
+}
+
+static void i2c_atmel_cancel(struct tpm_chip *chip)
+{
+ dev_err(chip->dev, "TPM operation cancellation was requested, but is not supported");
+}
+
+static u8 i2c_atmel_read_status(struct tpm_chip *chip)
+{
+ struct priv_data *priv = chip->vendor.priv;
+ struct i2c_client *client = to_i2c_client(chip->dev);
+ int rc;
+
+ /* The TPM fails the I2C read until it is ready, so we do the entire
+ * transfer here and buffer it locally. This way the common code can
+ * properly handle the timeouts. */
+ priv->len = 0;
+ memset(priv->buffer, 0, sizeof(priv->buffer));
+
+
+ /* Once the TPM has completed the command the command remains readable
+ * until another command is issued. */
+ rc = i2c_master_recv(client, priv->buffer, sizeof(priv->buffer));
+ dev_dbg(chip->dev,
+ "%s: sts=%d", __func__, rc);
+ if (rc <= 0)
+ return 0;
+
+ priv->len = rc;
+
+ return ATMEL_STS_OK;
+}
+
+static const struct file_operations i2c_atmel_ops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .open = tpm_open,
+ .read = tpm_read,
+ .write = tpm_write,
+ .release = tpm_release,
+};
+
+static DEVICE_ATTR(pubek, S_IRUGO, tpm_show_pubek, NULL);
+static DEVICE_ATTR(pcrs, S_IRUGO, tpm_show_pcrs, NULL);
+static DEVICE_ATTR(enabled, S_IRUGO, tpm_show_enabled, NULL);
+static DEVICE_ATTR(active, S_IRUGO, tpm_show_active, NULL);
+static DEVICE_ATTR(owned, S_IRUGO, tpm_show_owned, NULL);
+static DEVICE_ATTR(temp_deactivated, S_IRUGO, tpm_show_temp_deactivated, NULL);
+static DEVICE_ATTR(caps, S_IRUGO, tpm_show_caps, NULL);
+static DEVICE_ATTR(cancel, S_IWUSR | S_IWGRP, NULL, tpm_store_cancel);
+static DEVICE_ATTR(durations, S_IRUGO, tpm_show_durations, NULL);
+static DEVICE_ATTR(timeouts, S_IRUGO, tpm_show_timeouts, NULL);
+
+static struct attribute *i2c_atmel_attrs[] = {
+ &dev_attr_pubek.attr,
+ &dev_attr_pcrs.attr,
+ &dev_attr_enabled.attr,
+ &dev_attr_active.attr,
+ &dev_attr_owned.attr,
+ &dev_attr_temp_deactivated.attr,
+ &dev_attr_caps.attr,
+ &dev_attr_cancel.attr,
+ &dev_attr_durations.attr,
+ &dev_attr_timeouts.attr,
+ NULL,
+};
+
+static struct attribute_group i2c_atmel_attr_grp = {
+ .attrs = i2c_atmel_attrs
+};
+
+static bool i2c_atmel_req_canceled(struct tpm_chip *chip, u8 status)
+{
+ return 0;
+}
+
+static const struct tpm_vendor_specific i2c_atmel = {
+ .status = i2c_atmel_read_status,
+ .recv = i2c_atmel_recv,
+ .send = i2c_atmel_send,
+ .cancel = i2c_atmel_cancel,
+ .req_complete_mask = ATMEL_STS_OK,
+ .req_complete_val = ATMEL_STS_OK,
+ .req_canceled = i2c_atmel_req_canceled,
+ .attr_group = &i2c_atmel_attr_grp,
+ .miscdev.fops = &i2c_atmel_ops,
+};
+
+static int i2c_atmel_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int rc;
+ struct tpm_chip *chip;
+ struct device *dev = &client->dev;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ chip = tpm_register_hardware(dev, &i2c_atmel);
+ if (!chip) {
+ dev_err(dev, "%s() error in tpm_register_hardware\n", __func__);
+ return -ENODEV;
+ }
+
+ chip->vendor.priv = devm_kzalloc(dev, sizeof(struct priv_data),
+ GFP_KERNEL);
+
+ /* Default timeouts */
+ chip->vendor.timeout_a = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
+ chip->vendor.timeout_b = msecs_to_jiffies(TPM_I2C_LONG_TIMEOUT);
+ chip->vendor.timeout_c = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
+ chip->vendor.timeout_d = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
+ chip->vendor.irq = 0;
+
+ /* There is no known way to probe for this device, and all version
+ * information seems to be read via TPM commands. Thus we rely on the
+ * TPM startup process in the common code to detect the device. */
+ if (tpm_get_timeouts(chip)) {
+ rc = -ENODEV;
+ goto out_err;
+ }
+
+ if (tpm_do_selftest(chip)) {
+ rc = -ENODEV;
+ goto out_err;
+ }
+
+ return 0;
+
+out_err:
+ tpm_dev_vendor_release(chip);
+ tpm_remove_hardware(chip->dev);
+ return rc;
+}
+
+static int i2c_atmel_remove(struct i2c_client *client)
+{
+ struct device *dev = &(client->dev);
+ struct tpm_chip *chip = dev_get_drvdata(dev);
+
+ if (chip)
+ tpm_dev_vendor_release(chip);
+ tpm_remove_hardware(dev);
+ kfree(chip);
+ return 0;
+}
+
+static const struct i2c_device_id i2c_atmel_id[] = {
+ {I2C_DRIVER_NAME, 0},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, i2c_atmel_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id i2c_atmel_of_match[] = {
+ {.compatible = "atmel,at97sc3204t"},
+ {},
+};
+MODULE_DEVICE_TABLE(of, i2c_atmel_of_match);
+#endif
+
+static SIMPLE_DEV_PM_OPS(i2c_atmel_pm_ops, tpm_pm_suspend, tpm_pm_resume);
+
+static struct i2c_driver i2c_atmel_driver = {
+ .id_table = i2c_atmel_id,
+ .probe = i2c_atmel_probe,
+ .remove = i2c_atmel_remove,
+ .driver = {
+ .name = I2C_DRIVER_NAME,
+ .owner = THIS_MODULE,
+ .pm = &i2c_atmel_pm_ops,
+ .of_match_table = of_match_ptr(i2c_atmel_of_match),
+ },
+};
+
+module_i2c_driver(i2c_atmel_driver);
+
+MODULE_AUTHOR("Jason Gunthorpe <jgunthorpe@obsidianresearch.com>");
+MODULE_DESCRIPTION("Atmel TPM I2C Driver");
+MODULE_LICENSE("GPL");