diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-24 08:46:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-24 08:46:03 -0700 |
| commit | cf9610f9116d55c5a66ef9f1faecacabd93a9322 (patch) | |
| tree | 757a3d280760c654767631cab5ad8af2d86d1848 /security/loadpin/loadpin.c | |
| download | linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.tar.gz linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.zip | |
Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlgrafted
Pull pin control updates from Linus Walleij:
"Core changes:
- Use the non-blocking mux_state_try_select() in the generic MUX pin
control back-end
- Free pin maps on pinctrl_generic_to_map() failure in the core
helpers
New hardware pin control:
- Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC
(this is for the low power audio, LPASS = Low Power Audio SubSystem
portions)
- Upboard support on top of the Intel pin controller
- Apple T6030 and T6031 support (just compatible strings)
- Samsung Exynos 8855 SoC
- Mediatek MT6858 SoC
- Rockchip RK3308B and RV1106 SoCs
- Airoha EN7523 and AN7563 SoCs
Improvements:
- Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable
- Qualcomm improvements on top of the Qualcomm PDC (power domain
controller) irqchip improvements from tglx:s tree
- Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups
- The NPCM8xx driver has been put into shape fixing many pin and
group definitions
- Some non-urgent Tegra 264 pin assignments are fixed up
- Some non-urgent fixups to Airoha AN7581 and AN7583 registers and
pin assignments, missing features etc"
* tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits)
dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema
pinctrl: meson: sync some modify from A4
pinctrl: meson: a4: Add input enable pin configuration
pinctrl: realtek: rtd1625: remove unused group name spdif_sel
pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13
dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema
Revert "Merge branch 'ib-rsk7204' into devel"
pinctrl: rockchip: Add RV1106 pinctrl support
dt-bindings: pinctrl: rockchip: Add RV1106 compatible
pinctrl: rockchip: Decode drive strength in the get function
pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable
pinctrl: airoha: add support of an7563 SoC
dt-bindings: pinctrl: airoha: add support of an7563 pin controller
pinctrl: airoha: try to find chip scu node by phandle first
pinctrl: airoha: add support of en7523 SoC
dt-bindings: pinctrl: airoha: add support of en7523 pin controller
pinctrl: airoha: an7583: add support for olt pinmux
pinctrl: airoha: an7583: add support for pon_alt pinmux
pinctrl: airoha: an7583: add support for npu_uart pinmux
dt-bindings: pinctrl: airoha: an7583: add missed features
...
Diffstat (limited to 'security/loadpin/loadpin.c')
| -rw-r--r-- | security/loadpin/loadpin.c | 442 |
1 files changed, 442 insertions, 0 deletions
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c new file mode 100644 index 000000000..f71861f98 --- /dev/null +++ b/security/loadpin/loadpin.c @@ -0,0 +1,442 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Module and Firmware Pinning Security Module + * + * Copyright 2011-2016 Google Inc. + * + * Author: Kees Cook <keescook@chromium.org> + */ + +#define pr_fmt(fmt) "LoadPin: " fmt + +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/hex.h> +#include <linux/kernel_read_file.h> +#include <linux/lsm_hooks.h> +#include <linux/mount.h> +#include <linux/blkdev.h> +#include <linux/path.h> +#include <linux/sched.h> /* current */ +#include <linux/string_helpers.h> +#include <linux/dm-verity-loadpin.h> +#include <uapi/linux/loadpin.h> +#include <uapi/linux/lsm.h> + +#define VERITY_DIGEST_FILE_HEADER "# LOADPIN_TRUSTED_VERITY_ROOT_DIGESTS" + +static void report_load(const char *origin, struct file *file, char *operation) +{ + char *cmdline, *pathname; + + pathname = kstrdup_quotable_file(file, GFP_KERNEL); + cmdline = kstrdup_quotable_cmdline(current, GFP_KERNEL); + + pr_notice("%s %s obj=%s%s%s pid=%d cmdline=%s%s%s\n", + origin, operation, + (pathname && pathname[0] != '<') ? "\"" : "", + pathname, + (pathname && pathname[0] != '<') ? "\"" : "", + task_pid_nr(current), + cmdline ? "\"" : "", cmdline, cmdline ? "\"" : ""); + + kfree(cmdline); + kfree(pathname); +} + +static int enforce = IS_ENABLED(CONFIG_SECURITY_LOADPIN_ENFORCE); +static char *exclude_read_files[READING_MAX_ID]; +static int ignore_read_file_id[READING_MAX_ID] __ro_after_init; +static struct super_block *pinned_root; +static DEFINE_SPINLOCK(pinned_root_spinlock); +#ifdef CONFIG_SECURITY_LOADPIN_VERITY +static bool deny_reading_verity_digests; +#endif + +// initialized to false +static bool loadpin_root_writable; +#ifdef CONFIG_SYSCTL + +static int proc_handler_loadpin(const struct ctl_table *table, int dir, + void *buffer, size_t *lenp, loff_t *ppos) +{ + if (!loadpin_root_writable && SYSCTL_USER_TO_KERN(dir)) + return -EINVAL; + return proc_dointvec_minmax(table, dir, buffer, lenp, ppos); +} + +static const struct ctl_table loadpin_sysctl_table[] = { + { + .procname = "enforce", + .data = &enforce, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_handler_loadpin, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE, + }, +}; +#endif + +static void report_writable(struct super_block *mnt_sb, bool writable) +{ + if (mnt_sb->s_bdev) { + pr_info("%pg (%u:%u): %s\n", mnt_sb->s_bdev, + MAJOR(mnt_sb->s_bdev->bd_dev), + MINOR(mnt_sb->s_bdev->bd_dev), + writable ? "writable" : "read-only"); + } else + pr_info("mnt_sb lacks block device, treating as: writable\n"); + + if (!writable) + pr_info("load pinning engaged.\n"); +} + +/* + * This must be called after early kernel init, since then the rootdev + * is available. + */ +static bool sb_is_writable(struct super_block *mnt_sb) +{ + bool writable = true; + + if (mnt_sb->s_bdev) + writable = !bdev_read_only(mnt_sb->s_bdev); + + return writable; +} + +static void loadpin_sb_free_security(struct super_block *mnt_sb) +{ + /* + * When unmounting the filesystem we were using for load + * pinning, we acknowledge the superblock release, but make sure + * no other modules or firmware can be loaded when we are in + * enforcing mode. Otherwise, allow the root to be reestablished. + */ + if (!IS_ERR_OR_NULL(pinned_root) && mnt_sb == pinned_root) { + if (enforce) { + pinned_root = ERR_PTR(-EIO); + pr_info("umount pinned fs: refusing further loads\n"); + } else { + pinned_root = NULL; + } + } +} + +static int loadpin_check(struct file *file, enum kernel_read_file_id id) +{ + struct super_block *load_root; + const char *origin = kernel_read_file_id_str(id); + bool first_root_pin = false; + + /* If the file id is excluded, ignore the pinning. */ + if ((unsigned int)id < ARRAY_SIZE(ignore_read_file_id) && + ignore_read_file_id[id]) { + report_load(origin, file, "pinning-excluded"); + return 0; + } + + /* This handles the older init_module API that has a NULL file. */ + if (!file) { + if (!enforce) { + report_load(origin, NULL, "old-api-pinning-ignored"); + return 0; + } + + report_load(origin, NULL, "old-api-denied"); + return -EPERM; + } + + load_root = file->f_path.mnt->mnt_sb; + + /* First loaded module/firmware defines the root for all others. */ + spin_lock(&pinned_root_spinlock); + /* + * pinned_root is only NULL at startup or when the pinned root has + * been unmounted while we are not in enforcing mode. Otherwise, it + * is either a valid reference, or an ERR_PTR. + */ + if (!pinned_root) { + pinned_root = load_root; + first_root_pin = true; + } + spin_unlock(&pinned_root_spinlock); + + if (first_root_pin) { + loadpin_root_writable = sb_is_writable(pinned_root); + report_writable(pinned_root, loadpin_root_writable); + report_load(origin, file, "pinned"); + } + + if (IS_ERR_OR_NULL(pinned_root) || + ((load_root != pinned_root) && !dm_verity_loadpin_is_bdev_trusted(load_root->s_bdev))) { + if (unlikely(!enforce)) { + report_load(origin, file, "pinning-ignored"); + return 0; + } + + report_load(origin, file, "denied"); + return -EPERM; + } + + return 0; +} + +static int loadpin_read_file(struct file *file, enum kernel_read_file_id id, + bool contents) +{ + /* + * LoadPin only cares about the _origin_ of a file, not its + * contents, so we can ignore the "are full contents available" + * argument here. + */ + return loadpin_check(file, id); +} + +static int loadpin_load_data(enum kernel_load_data_id id, bool contents) +{ + /* + * LoadPin only cares about the _origin_ of a file, not its + * contents, so a NULL file is passed, and we can ignore the + * state of "contents". + */ + return loadpin_check(NULL, (enum kernel_read_file_id) id); +} + +static const struct lsm_id loadpin_lsmid = { + .name = "loadpin", + .id = LSM_ID_LOADPIN, +}; + +static struct security_hook_list loadpin_hooks[] __ro_after_init = { + LSM_HOOK_INIT(sb_free_security, loadpin_sb_free_security), + LSM_HOOK_INIT(kernel_read_file, loadpin_read_file), + LSM_HOOK_INIT(kernel_load_data, loadpin_load_data), +}; + +static void __init parse_exclude(void) +{ + int i, j; + char *cur; + + /* + * Make sure all the arrays stay within expected sizes. This + * is slightly weird because kernel_read_file_str[] includes + * READING_MAX_ID, which isn't actually meaningful here. + */ + BUILD_BUG_ON(ARRAY_SIZE(exclude_read_files) != + ARRAY_SIZE(ignore_read_file_id)); + BUILD_BUG_ON(ARRAY_SIZE(kernel_read_file_str) < + ARRAY_SIZE(ignore_read_file_id)); + + for (i = 0; i < ARRAY_SIZE(exclude_read_files); i++) { + cur = exclude_read_files[i]; + if (!cur) + break; + if (*cur == '\0') + continue; + + for (j = 0; j < ARRAY_SIZE(ignore_read_file_id); j++) { + if (strcmp(cur, kernel_read_file_str[j]) == 0) { + pr_info("excluding: %s\n", + kernel_read_file_str[j]); + ignore_read_file_id[j] = 1; + /* + * Can not break, because one read_file_str + * may map to more than on read_file_id. + */ + } + } + } +} + +static int __init loadpin_init(void) +{ + pr_info("ready to pin (currently %senforcing)\n", + enforce ? "" : "not "); + parse_exclude(); +#ifdef CONFIG_SYSCTL + if (!register_sysctl("kernel/loadpin", loadpin_sysctl_table)) + pr_notice("sysctl registration failed!\n"); +#endif + security_add_hooks(loadpin_hooks, ARRAY_SIZE(loadpin_hooks), + &loadpin_lsmid); + + return 0; +} + +#ifdef CONFIG_SECURITY_LOADPIN_VERITY + +enum loadpin_securityfs_interface_index { + LOADPIN_DM_VERITY, +}; + +static int read_trusted_verity_root_digests(unsigned int fd) +{ + void *data; + int rc; + char *p, *d; + + if (deny_reading_verity_digests) + return -EPERM; + + /* The list of trusted root digests can only be set up once */ + if (!list_empty(&dm_verity_loadpin_trusted_root_digests)) + return -EPERM; + + CLASS(fd, f)(fd); + if (fd_empty(f)) + return -EINVAL; + + data = kzalloc(SZ_4K, GFP_KERNEL); + if (!data) { + rc = -ENOMEM; + goto err; + } + + rc = kernel_read_file(fd_file(f), 0, (void **)&data, SZ_4K - 1, NULL, READING_POLICY); + if (rc < 0) + goto err; + + p = data; + p[rc] = '\0'; + p = strim(p); + + p = strim(data); + while ((d = strsep(&p, "\n")) != NULL) { + int len; + struct dm_verity_loadpin_trusted_root_digest *trd; + + if (d == data) { + /* first line, validate header */ + if (strcmp(d, VERITY_DIGEST_FILE_HEADER)) { + rc = -EPROTO; + goto err; + } + + continue; + } + + len = strlen(d); + + if (len % 2) { + rc = -EPROTO; + goto err; + } + + len /= 2; + + trd = kzalloc_flex(*trd, data, len); + if (!trd) { + rc = -ENOMEM; + goto err; + } + trd->len = len; + + if (hex2bin(trd->data, d, len)) { + kfree(trd); + rc = -EPROTO; + goto err; + } + + list_add_tail(&trd->node, &dm_verity_loadpin_trusted_root_digests); + } + + if (list_empty(&dm_verity_loadpin_trusted_root_digests)) { + rc = -EPROTO; + goto err; + } + + kfree(data); + + return 0; + +err: + kfree(data); + + /* any failure in loading/parsing invalidates the entire list */ + { + struct dm_verity_loadpin_trusted_root_digest *trd, *tmp; + + list_for_each_entry_safe(trd, tmp, &dm_verity_loadpin_trusted_root_digests, node) { + list_del(&trd->node); + kfree(trd); + } + } + + /* disallow further attempts after reading a corrupt/invalid file */ + deny_reading_verity_digests = true; + + return rc; +} + +/******************************** securityfs ********************************/ + +static long dm_verity_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) +{ + void __user *uarg = (void __user *)arg; + unsigned int fd; + + switch (cmd) { + case LOADPIN_IOC_SET_TRUSTED_VERITY_DIGESTS: + if (copy_from_user(&fd, uarg, sizeof(fd))) + return -EFAULT; + + return read_trusted_verity_root_digests(fd); + + default: + return -EINVAL; + } +} + +static const struct file_operations loadpin_dm_verity_ops = { + .unlocked_ioctl = dm_verity_ioctl, + .compat_ioctl = compat_ptr_ioctl, +}; + +/** + * init_loadpin_securityfs - create the securityfs directory for LoadPin + * + * We can not put this method normally under the loadpin_init() code path since + * the security subsystem gets initialized before the vfs caches. + * + * Returns 0 if the securityfs directory creation was successful. + */ +static int __init init_loadpin_securityfs(void) +{ + struct dentry *loadpin_dir, *dentry; + + loadpin_dir = securityfs_create_dir("loadpin", NULL); + if (IS_ERR(loadpin_dir)) { + pr_err("LoadPin: could not create securityfs dir: %ld\n", + PTR_ERR(loadpin_dir)); + return PTR_ERR(loadpin_dir); + } + + dentry = securityfs_create_file("dm-verity", 0600, loadpin_dir, + (void *)LOADPIN_DM_VERITY, &loadpin_dm_verity_ops); + if (IS_ERR(dentry)) { + pr_err("LoadPin: could not create securityfs entry 'dm-verity': %ld\n", + PTR_ERR(dentry)); + return PTR_ERR(dentry); + } + + return 0; +} + +#endif /* CONFIG_SECURITY_LOADPIN_VERITY */ + +DEFINE_LSM(loadpin) = { + .id = &loadpin_lsmid, + .init = loadpin_init, +#ifdef CONFIG_SECURITY_LOADPIN_VERITY + .initcall_fs = init_loadpin_securityfs, +#endif /* CONFIG_SECURITY_LOADPIN_VERITY */ +}; + +/* Should not be mutable after boot, so not listed in sysfs (perm == 0). */ +module_param(enforce, int, 0); +MODULE_PARM_DESC(enforce, "Enforce module/firmware pinning"); +module_param_array_named(exclude, exclude_read_files, charp, NULL, 0); +MODULE_PARM_DESC(exclude, "Exclude pinning specific read file types"); |
