From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:05:51 +0200 Subject: Adding upstream version 5.10.209. Signed-off-by: Daniel Baumann --- security/integrity/ima/ima_fs.c | 507 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 507 insertions(+) create mode 100644 security/integrity/ima/ima_fs.c (limited to 'security/integrity/ima/ima_fs.c') diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c new file mode 100644 index 000000000..98d5a800f --- /dev/null +++ b/security/integrity/ima/ima_fs.c @@ -0,0 +1,507 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2005,2006,2007,2008 IBM Corporation + * + * Authors: + * Kylene Hall + * Reiner Sailer + * Mimi Zohar + * + * File: ima_fs.c + * implemenents security file system for reporting + * current measurement list and IMA statistics + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "ima.h" + +static DEFINE_MUTEX(ima_write_mutex); + +bool ima_canonical_fmt; +static int __init default_canonical_fmt_setup(char *str) +{ +#ifdef __BIG_ENDIAN + ima_canonical_fmt = true; +#endif + return 1; +} +__setup("ima_canonical_fmt", default_canonical_fmt_setup); + +static int valid_policy = 1; + +static ssize_t ima_show_htable_value(char __user *buf, size_t count, + loff_t *ppos, atomic_long_t *val) +{ + char tmpbuf[32]; /* greater than largest 'long' string value */ + ssize_t len; + + len = scnprintf(tmpbuf, sizeof(tmpbuf), "%li\n", atomic_long_read(val)); + return simple_read_from_buffer(buf, count, ppos, tmpbuf, len); +} + +static ssize_t ima_show_htable_violations(struct file *filp, + char __user *buf, + size_t count, loff_t *ppos) +{ + return ima_show_htable_value(buf, count, ppos, &ima_htable.violations); +} + +static const struct file_operations ima_htable_violations_ops = { + .read = ima_show_htable_violations, + .llseek = generic_file_llseek, +}; + +static ssize_t ima_show_measurements_count(struct file *filp, + char __user *buf, + size_t count, loff_t *ppos) +{ + return ima_show_htable_value(buf, count, ppos, &ima_htable.len); + +} + +static const struct file_operations ima_measurements_count_ops = { + .read = ima_show_measurements_count, + .llseek = generic_file_llseek, +}; + +/* returns pointer to hlist_node */ +static void *ima_measurements_start(struct seq_file *m, loff_t *pos) +{ + loff_t l = *pos; + struct ima_queue_entry *qe; + + /* we need a lock since pos could point beyond last element */ + rcu_read_lock(); + list_for_each_entry_rcu(qe, &ima_measurements, later) { + if (!l--) { + rcu_read_unlock(); + return qe; + } + } + rcu_read_unlock(); + return NULL; +} + +static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct ima_queue_entry *qe = v; + + /* lock protects when reading beyond last element + * against concurrent list-extension + */ + rcu_read_lock(); + qe = list_entry_rcu(qe->later.next, struct ima_queue_entry, later); + rcu_read_unlock(); + (*pos)++; + + return (&qe->later == &ima_measurements) ? NULL : qe; +} + +static void ima_measurements_stop(struct seq_file *m, void *v) +{ +} + +void ima_putc(struct seq_file *m, void *data, int datalen) +{ + while (datalen--) + seq_putc(m, *(char *)data++); +} + +/* print format: + * 32bit-le=pcr# + * char[20]=template digest + * 32bit-le=template name size + * char[n]=template name + * [eventdata length] + * eventdata[n]=template specific data + */ +int ima_measurements_show(struct seq_file *m, void *v) +{ + /* the list never shrinks, so we don't need a lock here */ + struct ima_queue_entry *qe = v; + struct ima_template_entry *e; + char *template_name; + u32 pcr, namelen, template_data_len; /* temporary fields */ + bool is_ima_template = false; + int i; + + /* get entry */ + e = qe->entry; + if (e == NULL) + return -1; + + template_name = (e->template_desc->name[0] != '\0') ? + e->template_desc->name : e->template_desc->fmt; + + /* + * 1st: PCRIndex + * PCR used defaults to the same (config option) in + * little-endian format, unless set in policy + */ + pcr = !ima_canonical_fmt ? e->pcr : cpu_to_le32(e->pcr); + ima_putc(m, &pcr, sizeof(e->pcr)); + + /* 2nd: template digest */ + ima_putc(m, e->digests[ima_sha1_idx].digest, TPM_DIGEST_SIZE); + + /* 3rd: template name size */ + namelen = !ima_canonical_fmt ? strlen(template_name) : + cpu_to_le32(strlen(template_name)); + ima_putc(m, &namelen, sizeof(namelen)); + + /* 4th: template name */ + ima_putc(m, template_name, strlen(template_name)); + + /* 5th: template length (except for 'ima' template) */ + if (strcmp(template_name, IMA_TEMPLATE_IMA_NAME) == 0) + is_ima_template = true; + + if (!is_ima_template) { + template_data_len = !ima_canonical_fmt ? e->template_data_len : + cpu_to_le32(e->template_data_len); + ima_putc(m, &template_data_len, sizeof(e->template_data_len)); + } + + /* 6th: template specific data */ + for (i = 0; i < e->template_desc->num_fields; i++) { + enum ima_show_type show = IMA_SHOW_BINARY; + 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; + if (is_ima_template && strcmp(field->field_id, "n") == 0) + show = IMA_SHOW_BINARY_OLD_STRING_FMT; + field->field_show(m, show, &e->template_data[i]); + } + return 0; +} + +static const struct seq_operations ima_measurments_seqops = { + .start = ima_measurements_start, + .next = ima_measurements_next, + .stop = ima_measurements_stop, + .show = ima_measurements_show +}; + +static int ima_measurements_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &ima_measurments_seqops); +} + +static const struct file_operations ima_measurements_ops = { + .open = ima_measurements_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +void ima_print_digest(struct seq_file *m, u8 *digest, u32 size) +{ + u32 i; + + for (i = 0; i < size; i++) + seq_printf(m, "%02x", *(digest + i)); +} + +/* print in ascii */ +static int ima_ascii_measurements_show(struct seq_file *m, void *v) +{ + /* the list never shrinks, so we don't need a lock here */ + struct ima_queue_entry *qe = v; + struct ima_template_entry *e; + char *template_name; + int i; + + /* get entry */ + e = qe->entry; + if (e == NULL) + return -1; + + template_name = (e->template_desc->name[0] != '\0') ? + e->template_desc->name : e->template_desc->fmt; + + /* 1st: PCR used (config option) */ + seq_printf(m, "%2d ", e->pcr); + + /* 2nd: SHA1 template hash */ + ima_print_digest(m, e->digests[ima_sha1_idx].digest, TPM_DIGEST_SIZE); + + /* 3th: template name */ + seq_printf(m, " %s", template_name); + + /* 4th: template specific data */ + for (i = 0; i < e->template_desc->num_fields; i++) { + seq_puts(m, " "); + if (e->template_data[i].len == 0) + continue; + + e->template_desc->fields[i]->field_show(m, IMA_SHOW_ASCII, + &e->template_data[i]); + } + seq_puts(m, "\n"); + return 0; +} + +static const struct seq_operations ima_ascii_measurements_seqops = { + .start = ima_measurements_start, + .next = ima_measurements_next, + .stop = ima_measurements_stop, + .show = ima_ascii_measurements_show +}; + +static int ima_ascii_measurements_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &ima_ascii_measurements_seqops); +} + +static const struct file_operations ima_ascii_measurements_ops = { + .open = ima_ascii_measurements_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +static ssize_t ima_read_policy(char *path) +{ + void *data = NULL; + char *datap; + size_t size; + int rc, pathlen = strlen(path); + + char *p; + + /* remove \n */ + datap = path; + strsep(&datap, "\n"); + + rc = kernel_read_file_from_path(path, 0, &data, INT_MAX, NULL, + READING_POLICY); + if (rc < 0) { + pr_err("Unable to open file: %s (%d)", path, rc); + return rc; + } + size = rc; + rc = 0; + + datap = data; + while (size > 0 && (p = strsep(&datap, "\n"))) { + pr_debug("rule: %s\n", p); + rc = ima_parse_add_rule(p); + if (rc < 0) + break; + size -= rc; + } + + vfree(data); + if (rc < 0) + return rc; + else if (size) + return -EINVAL; + else + return pathlen; +} + +static ssize_t ima_write_policy(struct file *file, const char __user *buf, + size_t datalen, loff_t *ppos) +{ + char *data; + ssize_t result; + + if (datalen >= PAGE_SIZE) + datalen = PAGE_SIZE - 1; + + /* No partial writes. */ + result = -EINVAL; + if (*ppos != 0) + goto out; + + data = memdup_user_nul(buf, datalen); + if (IS_ERR(data)) { + result = PTR_ERR(data); + goto out; + } + + result = mutex_lock_interruptible(&ima_write_mutex); + if (result < 0) + goto out_free; + + if (data[0] == '/') { + result = ima_read_policy(data); + } else if (ima_appraise & IMA_APPRAISE_POLICY) { + pr_err("signed policy file (specified as an absolute pathname) required\n"); + integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL, + "policy_update", "signed policy required", + 1, 0); + result = -EACCES; + } else { + result = ima_parse_add_rule(data); + } + mutex_unlock(&ima_write_mutex); +out_free: + kfree(data); +out: + if (result < 0) + valid_policy = 0; + + return result; +} + +static struct dentry *ima_dir; +static struct dentry *ima_symlink; +static struct dentry *binary_runtime_measurements; +static struct dentry *ascii_runtime_measurements; +static struct dentry *runtime_measurements_count; +static struct dentry *violations; +static struct dentry *ima_policy; + +enum ima_fs_flags { + IMA_FS_BUSY, +}; + +static unsigned long ima_fs_flags; + +#ifdef CONFIG_IMA_READ_POLICY +static const struct seq_operations ima_policy_seqops = { + .start = ima_policy_start, + .next = ima_policy_next, + .stop = ima_policy_stop, + .show = ima_policy_show, +}; +#endif + +/* + * ima_open_policy: sequentialize access to the policy file + */ +static int ima_open_policy(struct inode *inode, struct file *filp) +{ + if (!(filp->f_flags & O_WRONLY)) { +#ifndef CONFIG_IMA_READ_POLICY + return -EACCES; +#else + if ((filp->f_flags & O_ACCMODE) != O_RDONLY) + return -EACCES; + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + return seq_open(filp, &ima_policy_seqops); +#endif + } + if (test_and_set_bit(IMA_FS_BUSY, &ima_fs_flags)) + return -EBUSY; + return 0; +} + +/* + * ima_release_policy - start using the new measure policy rules. + * + * Initially, ima_measure points to the default policy rules, now + * point to the new policy rules, and remove the securityfs policy file, + * assuming a valid policy. + */ +static int ima_release_policy(struct inode *inode, struct file *file) +{ + const char *cause = valid_policy ? "completed" : "failed"; + + if ((file->f_flags & O_ACCMODE) == O_RDONLY) + return seq_release(inode, file); + + if (valid_policy && ima_check_policy() < 0) { + cause = "failed"; + valid_policy = 0; + } + + pr_info("policy update %s\n", cause); + integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL, + "policy_update", cause, !valid_policy, 0); + + if (!valid_policy) { + ima_delete_rules(); + valid_policy = 1; + clear_bit(IMA_FS_BUSY, &ima_fs_flags); + return 0; + } + + ima_update_policy(); +#if !defined(CONFIG_IMA_WRITE_POLICY) && !defined(CONFIG_IMA_READ_POLICY) + securityfs_remove(ima_policy); + ima_policy = NULL; +#elif defined(CONFIG_IMA_WRITE_POLICY) + clear_bit(IMA_FS_BUSY, &ima_fs_flags); +#elif defined(CONFIG_IMA_READ_POLICY) + inode->i_mode &= ~S_IWUSR; +#endif + return 0; +} + +static const struct file_operations ima_measure_policy_ops = { + .open = ima_open_policy, + .write = ima_write_policy, + .read = seq_read, + .release = ima_release_policy, + .llseek = generic_file_llseek, +}; + +int __init ima_fs_init(void) +{ + ima_dir = securityfs_create_dir("ima", integrity_dir); + if (IS_ERR(ima_dir)) + return -1; + + ima_symlink = securityfs_create_symlink("ima", NULL, "integrity/ima", + NULL); + if (IS_ERR(ima_symlink)) + goto out; + + binary_runtime_measurements = + securityfs_create_file("binary_runtime_measurements", + S_IRUSR | S_IRGRP, ima_dir, NULL, + &ima_measurements_ops); + if (IS_ERR(binary_runtime_measurements)) + goto out; + + ascii_runtime_measurements = + securityfs_create_file("ascii_runtime_measurements", + S_IRUSR | S_IRGRP, ima_dir, NULL, + &ima_ascii_measurements_ops); + if (IS_ERR(ascii_runtime_measurements)) + goto out; + + runtime_measurements_count = + securityfs_create_file("runtime_measurements_count", + S_IRUSR | S_IRGRP, ima_dir, NULL, + &ima_measurements_count_ops); + if (IS_ERR(runtime_measurements_count)) + goto out; + + violations = + securityfs_create_file("violations", S_IRUSR | S_IRGRP, + ima_dir, NULL, &ima_htable_violations_ops); + if (IS_ERR(violations)) + goto out; + + ima_policy = securityfs_create_file("policy", POLICY_FILE_FLAGS, + ima_dir, NULL, + &ima_measure_policy_ops); + if (IS_ERR(ima_policy)) + goto out; + + return 0; +out: + securityfs_remove(ima_policy); + securityfs_remove(violations); + securityfs_remove(runtime_measurements_count); + securityfs_remove(ascii_runtime_measurements); + securityfs_remove(binary_runtime_measurements); + securityfs_remove(ima_symlink); + securityfs_remove(ima_dir); + return -1; +} -- cgit v1.2.3