diff options
| -rw-r--r-- | MAINTAINERS | 5 | ||||
| -rw-r--r-- | drivers/base/firmware_loader/fallback.c | 7 | ||||
| -rw-r--r-- | include/linux/ima.h | 7 | ||||
| -rw-r--r-- | include/linux/lsm_hooks.h | 6 | ||||
| -rw-r--r-- | include/linux/security.h | 27 | ||||
| -rw-r--r-- | kernel/kexec.c | 8 | ||||
| -rw-r--r-- | kernel/module.c | 2 | ||||
| -rw-r--r-- | security/integrity/ima/Kconfig | 58 | ||||
| -rw-r--r-- | security/integrity/ima/ima.h | 1 | ||||
| -rw-r--r-- | security/integrity/ima/ima_main.c | 68 | ||||
| -rw-r--r-- | security/integrity/ima/ima_policy.c | 48 | ||||
| -rw-r--r-- | security/loadpin/loadpin.c | 6 | ||||
| -rw-r--r-- | security/security.c | 13 | ||||
| -rw-r--r-- | security/selinux/hooks.c | 15 |
14 files changed, 248 insertions, 23 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index f7a8faf07a4e..a95a7e63ae55 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -8342,11 +8342,6 @@ F: Documentation/core-api/atomic_ops.rst F: Documentation/core-api/refcount-vs-atomic.rst F: Documentation/memory-barriers.txt -LINUX SECURITY MODULE (LSM) FRAMEWORK -M: Chris Wright <chrisw@sous-sol.org> -L: linux-security-module@vger.kernel.org -S: Supported - LIS3LV02D ACCELEROMETER DRIVER M: Eric Piel <eric.piel@tremplin-utc.net> S: Maintained diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c index 7f732744f0d3..202324291542 100644 --- a/drivers/base/firmware_loader/fallback.c +++ b/drivers/base/firmware_loader/fallback.c @@ -651,6 +651,8 @@ static bool fw_force_sysfs_fallback(enum fw_opt opt_flags) static bool fw_run_sysfs_fallback(enum fw_opt opt_flags) { + int ret; + if (fw_fallback_config.ignore_sysfs_fallback) { pr_info_once("Ignoring firmware sysfs fallback due to sysctl knob\n"); return false; @@ -659,6 +661,11 @@ static bool fw_run_sysfs_fallback(enum fw_opt opt_flags) if ((opt_flags & FW_OPT_NOFALLBACK)) return false; + /* Also permit LSMs and IMA to fail firmware sysfs fallback */ + ret = security_kernel_load_data(LOADING_FIRMWARE); + if (ret < 0) + return ret; + return fw_force_sysfs_fallback(opt_flags); } diff --git a/include/linux/ima.h b/include/linux/ima.h index d9ba3fc363b7..97914a2833d1 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -11,6 +11,7 @@ #define _LINUX_IMA_H #include <linux/fs.h> +#include <linux/security.h> #include <linux/kexec.h> struct linux_binprm; @@ -19,6 +20,7 @@ extern int ima_bprm_check(struct linux_binprm *bprm); extern int ima_file_check(struct file *file, int mask); extern void ima_file_free(struct file *file); extern int ima_file_mmap(struct file *file, unsigned long prot); +extern int ima_load_data(enum kernel_load_data_id id); extern int ima_read_file(struct file *file, enum kernel_read_file_id id); extern int ima_post_read_file(struct file *file, void *buf, loff_t size, enum kernel_read_file_id id); @@ -49,6 +51,11 @@ static inline int ima_file_mmap(struct file *file, unsigned long prot) return 0; } +static inline int ima_load_data(enum kernel_load_data_id id) +{ + return 0; +} + static inline int ima_read_file(struct file *file, enum kernel_read_file_id id) { return 0; diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index a8ee106b865d..97a020c616ad 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -576,6 +576,10 @@ * userspace to load a kernel module with the given name. * @kmod_name name of the module requested by the kernel * Return 0 if successful. + * @kernel_load_data: + * Load data provided by userspace. + * @id kernel load data identifier + * Return 0 if permission is granted. * @kernel_read_file: * Read a file specified by userspace. * @file contains the file structure pointing to the file being read @@ -1582,6 +1586,7 @@ union security_list_options { int (*kernel_act_as)(struct cred *new, u32 secid); int (*kernel_create_files_as)(struct cred *new, struct inode *inode); int (*kernel_module_request)(char *kmod_name); + int (*kernel_load_data)(enum kernel_load_data_id id); int (*kernel_read_file)(struct file *file, enum kernel_read_file_id id); int (*kernel_post_read_file)(struct file *file, char *buf, loff_t size, enum kernel_read_file_id id); @@ -1872,6 +1877,7 @@ struct security_hook_heads { struct hlist_head cred_getsecid; struct hlist_head kernel_act_as; struct hlist_head kernel_create_files_as; + struct hlist_head kernel_load_data; struct hlist_head kernel_read_file; struct hlist_head kernel_post_read_file; struct hlist_head kernel_module_request; diff --git a/include/linux/security.h b/include/linux/security.h index 88d30fc975e7..75f4156c84d7 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -159,6 +159,27 @@ extern int mmap_min_addr_handler(struct ctl_table *table, int write, typedef int (*initxattrs) (struct inode *inode, const struct xattr *xattr_array, void *fs_data); + +/* Keep the kernel_load_data_id enum in sync with kernel_read_file_id */ +#define __data_id_enumify(ENUM, dummy) LOADING_ ## ENUM, +#define __data_id_stringify(dummy, str) #str, + +enum kernel_load_data_id { + __kernel_read_file_id(__data_id_enumify) +}; + +static const char * const kernel_load_data_str[] = { + __kernel_read_file_id(__data_id_stringify) +}; + +static inline const char *kernel_load_data_id_str(enum kernel_load_data_id id) +{ + if ((unsigned)id >= LOADING_MAX_ID) + return kernel_load_data_str[LOADING_UNKNOWN]; + + return kernel_load_data_str[id]; +} + #ifdef CONFIG_SECURITY struct security_mnt_opts { @@ -320,6 +341,7 @@ void security_cred_getsecid(const struct cred *c, u32 *secid); int security_kernel_act_as(struct cred *new, u32 secid); int security_kernel_create_files_as(struct cred *new, struct inode *inode); int security_kernel_module_request(char *kmod_name); +int security_kernel_load_data(enum kernel_load_data_id id); int security_kernel_read_file(struct file *file, enum kernel_read_file_id id); int security_kernel_post_read_file(struct file *file, char *buf, loff_t size, enum kernel_read_file_id id); @@ -908,6 +930,11 @@ static inline int security_kernel_module_request(char *kmod_name) return 0; } +static inline int security_kernel_load_data(enum kernel_load_data_id id) +{ + return 0; +} + static inline int security_kernel_read_file(struct file *file, enum kernel_read_file_id id) { diff --git a/kernel/kexec.c b/kernel/kexec.c index aed8fb2564b3..68559808fdfa 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -11,6 +11,7 @@ #include <linux/capability.h> #include <linux/mm.h> #include <linux/file.h> +#include <linux/security.h> #include <linux/kexec.h> #include <linux/mutex.h> #include <linux/list.h> @@ -195,10 +196,17 @@ out: static inline int kexec_load_check(unsigned long nr_segments, unsigned long flags) { + int result; + /* We only trust the superuser with rebooting the system. */ if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) return -EPERM; + /* Permit LSMs and IMA to fail the kexec */ + result = security_kernel_load_data(LOADING_KEXEC_IMAGE); + if (result < 0) + return result; + /* * Verify we have a legal set of flags * This leaves us room for future extensions. diff --git a/kernel/module.c b/kernel/module.c index f475f30eed8c..a7615d661910 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2876,7 +2876,7 @@ static int copy_module_from_user(const void __user *umod, unsigned long len, if (info->len < sizeof(*(info->hdr))) return -ENOEXEC; - err = security_kernel_read_file(NULL, READING_MODULE); + err = security_kernel_load_data(LOADING_MODULE); if (err) return err; diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index 6a8f67714c83..004919d9bf09 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -156,6 +156,64 @@ config IMA_APPRAISE <http://linux-ima.sourceforge.net> If unsure, say N. +config IMA_APPRAISE_BUILD_POLICY + bool "IMA build time configured policy rules" + depends on IMA_APPRAISE && INTEGRITY_ASYMMETRIC_KEYS + default n + help + This option defines an IMA appraisal policy at build time, which + is enforced at run time without having to specify a builtin + policy name on the boot command line. The build time appraisal + policy rules persist after loading a custom policy. + + Depending on the rules configured, this policy may require kernel + modules, firmware, the kexec kernel image, and/or the IMA policy + to be signed. Unsigned files might prevent the system from + booting or applications from working properly. + +config IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS + bool "Appraise firmware signatures" + depends on IMA_APPRAISE_BUILD_POLICY + default n + help + This option defines a policy requiring all firmware to be signed, + including the regulatory.db. If both this option and + CFG80211_REQUIRE_SIGNED_REGDB are enabled, then both signature + verification methods are necessary. + +config IMA_APPRAISE_REQUIRE_KEXEC_SIGS + bool "Appraise kexec kernel image signatures" + depends on IMA_APPRAISE_BUILD_POLICY + default n + help + Enabling this rule will require all kexec'ed kernel images to + be signed and verified by a public key on the trusted IMA + keyring. + + Kernel image signatures can not be verified by the original + kexec_load syscall. Enabling this rule will prevent its + usage. + +config IMA_APPRAISE_REQUIRE_MODULE_SIGS + bool "Appraise kernel modules signatures" + depends on IMA_APPRAISE_BUILD_POLICY + default n + help + Enabling this rule will require all kernel modules to be signed + and verified by a public key on the trusted IMA keyring. + + Kernel module signatures can only be verified by IMA-appraisal, + via the finit_module syscall. Enabling this rule will prevent + the usage of the init_module syscall. + +config IMA_APPRAISE_REQUIRE_POLICY_SIGS + bool "Appraise IMA policy signature" + depends on IMA_APPRAISE_BUILD_POLICY + default n + help + Enabling this rule will require the IMA policy to be signed and + and verified by a key on the trusted IMA keyring. + config IMA_APPRAISE_BOOTPARAM bool "ima_appraise boot parameter" depends on IMA_APPRAISE diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index e4c1a236976c..a597b2795d2d 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -232,6 +232,7 @@ int ima_policy_show(struct seq_file *m, void *v); #define IMA_APPRAISE_MODULES 0x08 #define IMA_APPRAISE_FIRMWARE 0x10 #define IMA_APPRAISE_POLICY 0x20 +#define IMA_APPRAISE_KEXEC 0x40 #ifdef CONFIG_IMA_APPRAISE int ima_appraise_measurement(enum ima_hooks func, diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index b286f37712d5..2d31921fbda4 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -429,16 +429,14 @@ void ima_post_path_mknod(struct dentry *dentry) */ int ima_read_file(struct file *file, enum kernel_read_file_id read_id) { - bool sig_enforce = is_module_sig_enforced(); - - if (!file && read_id == READING_MODULE) { - if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES) && - (ima_appraise & IMA_APPRAISE_ENFORCE)) { - pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n"); - return -EACCES; /* INTEGRITY_UNKNOWN */ - } - return 0; /* We rely on module signature checking */ - } + /* + * READING_FIRMWARE_PREALLOC_BUFFER + * + * Do devices using pre-allocated memory run the risk of the + * firmware being accessible to the device prior to the completion + * of IMA's signature verification any more than when using two + * buffers? + */ return 0; } @@ -472,14 +470,13 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size, if (!file && read_id == READING_FIRMWARE) { if ((ima_appraise & IMA_APPRAISE_FIRMWARE) && - (ima_appraise & IMA_APPRAISE_ENFORCE)) + (ima_appraise & IMA_APPRAISE_ENFORCE)) { + pr_err("Prevent firmware loading_store.\n"); return -EACCES; /* INTEGRITY_UNKNOWN */ + } return 0; } - if (!file && read_id == READING_MODULE) /* MODULE_SIG_FORCE enabled */ - return 0; - /* permit signed certs */ if (!file && read_id == READING_X509_CERTIFICATE) return 0; @@ -496,6 +493,49 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size, MAY_READ, func); } +/** + * ima_load_data - appraise decision based on policy + * @id: kernel load data caller identifier + * + * Callers of this LSM hook can not measure, appraise, or audit the + * data provided by userspace. Enforce policy rules requring a file + * signature (eg. kexec'ed kernel image). + * + * For permission return 0, otherwise return -EACCES. + */ +int ima_load_data(enum kernel_load_data_id id) +{ + bool sig_enforce; + + if ((ima_appraise & IMA_APPRAISE_ENFORCE) != IMA_APPRAISE_ENFORCE) + return 0; + + switch (id) { + case LOADING_KEXEC_IMAGE: + if (ima_appraise & IMA_APPRAISE_KEXEC) { + pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n"); + return -EACCES; /* INTEGRITY_UNKNOWN */ + } + break; + case LOADING_FIRMWARE: + if (ima_appraise & IMA_APPRAISE_FIRMWARE) { + pr_err("Prevent firmware sysfs fallback loading.\n"); + return -EACCES; /* INTEGRITY_UNKNOWN */ + } + break; + case LOADING_MODULE: + sig_enforce = is_module_sig_enforced(); + + if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES)) { + pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n"); + return -EACCES; /* INTEGRITY_UNKNOWN */ + } + default: + break; + } + return 0; +} + static int __init init_ima(void) { int error; diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index cdcc9a7b4e24..1659abb344f9 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -49,6 +49,7 @@ int ima_policy_flag; static int temp_ima_appraise; +static int build_ima_appraise __ro_after_init; #define MAX_LSM_RULES 6 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE, @@ -162,6 +163,25 @@ static struct ima_rule_entry default_appraise_rules[] __ro_after_init = { #endif }; +static struct ima_rule_entry build_appraise_rules[] __ro_after_init = { +#ifdef CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS + {.action = APPRAISE, .func = MODULE_CHECK, + .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED}, +#endif +#ifdef CONFIG_IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS + {.action = APPRAISE, .func = FIRMWARE_CHECK, + .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED}, +#endif +#ifdef CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS + {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK, + .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED}, +#endif +#ifdef CONFIG_IMA_APPRAISE_REQUIRE_POLICY_SIGS + {.action = APPRAISE, .func = POLICY_CHECK, + .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED}, +#endif +}; + static struct ima_rule_entry secure_boot_rules[] __ro_after_init = { {.action = APPRAISE, .func = MODULE_CHECK, .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED}, @@ -435,7 +455,7 @@ void ima_update_policy_flag(void) ima_policy_flag |= entry->action; } - ima_appraise |= temp_ima_appraise; + ima_appraise |= (build_ima_appraise | temp_ima_appraise); if (!ima_appraise) ima_policy_flag &= ~IMA_APPRAISE; } @@ -448,6 +468,8 @@ static int ima_appraise_flag(enum ima_hooks func) return IMA_APPRAISE_FIRMWARE; else if (func == POLICY_CHECK) return IMA_APPRAISE_POLICY; + else if (func == KEXEC_KERNEL_CHECK) + return IMA_APPRAISE_KEXEC; return 0; } @@ -486,8 +508,8 @@ void __init ima_init_policy(void) } /* - * Insert the appraise rules requiring file signatures, prior to - * any other appraise rules. + * Insert the builtin "secure_boot" policy rules requiring file + * signatures, prior to any other appraise rules. */ for (i = 0; i < secure_boot_entries; i++) { list_add_tail(&secure_boot_rules[i].list, &ima_default_rules); @@ -495,6 +517,26 @@ void __init ima_init_policy(void) ima_appraise_flag(secure_boot_rules[i].func); } + /* + * Insert the build time appraise rules requiring file signatures + * for both the initial and custom policies, prior to other appraise + * rules. + */ + for (i = 0; i < ARRAY_SIZE(build_appraise_rules); i++) { + struct ima_rule_entry *entry; + + if (!secure_boot_entries) + list_add_tail(&build_appraise_rules[i].list, + &ima_default_rules); + + entry = kmemdup(&build_appraise_rules[i], sizeof(*entry), + GFP_KERNEL); + if (entry) + list_add_tail(&entry->list, &ima_policy_rules); + build_ima_appraise |= + ima_appraise_flag(build_appraise_rules[i].func); + } + for (i = 0; i < appraise_entries; i++) { list_add_tail(&default_appraise_rules[i].list, &ima_default_rules); diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c index 5fa191252c8f..0716af28808a 100644 --- a/security/loadpin/loadpin.c +++ b/security/loadpin/loadpin.c @@ -173,9 +173,15 @@ static int loadpin_read_file(struct file *file, enum kernel_read_file_id id) return 0; } +static int loadpin_load_data(enum kernel_load_data_id id) +{ + return loadpin_read_file(NULL, (enum kernel_read_file_id) id); +} + static struct security_hook_list loadpin_hooks[] __lsm_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), }; void __init loadpin_add_hooks(void) diff --git a/security/security.c b/security/security.c index 5dce67070cdf..ab4f96347ebb 100644 --- a/security/security.c +++ b/security/security.c @@ -118,6 +118,8 @@ static int lsm_append(char *new, char **result) if (*result == NULL) { *result = kstrdup(new, GFP_KERNEL); + if (*result == NULL) + return -ENOMEM; } else { /* Check if it is the last registered name */ if (match_last_lsm(*result, new)) @@ -1056,6 +1058,17 @@ int security_kernel_post_read_file(struct file *file, char *buf, loff_t size, } EXPORT_SYMBOL_GPL(security_kernel_post_read_file); +int security_kernel_load_data(enum kernel_load_data_id id) +{ + int ret; + + ret = call_int_hook(kernel_load_data, 0, id); + if (ret) + return ret; + return ima_load_data(id); +} +EXPORT_SYMBOL_GPL(security_kernel_load_data); + int security_task_fix_setuid(struct cred *new, const struct cred *old, int flags) { diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 18006be15713..589c6b4023ce 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -4073,6 +4073,20 @@ static int selinux_kernel_read_file(struct file *file, return rc; } +static int selinux_kernel_load_data(enum kernel_load_data_id id) +{ + int rc = 0; + + switch (id) { + case LOADING_MODULE: + rc = selinux_kernel_module_from_file(NULL); + default: + break; + } + + return rc; +} + static int selinux_task_setpgid(struct task_struct *p, pid_t pgid) { return avc_has_perm(&selinux_state, @@ -6972,6 +6986,7 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(kernel_act_as, selinux_kernel_act_as), LSM_HOOK_INIT(kernel_create_files_as, selinux_kernel_create_files_as), LSM_HOOK_INIT(kernel_module_request, selinux_kernel_module_request), + LSM_HOOK_INIT(kernel_load_data, selinux_kernel_load_data), LSM_HOOK_INIT(kernel_read_file, selinux_kernel_read_file), LSM_HOOK_INIT(task_setpgid, selinux_task_setpgid), LSM_HOOK_INIT(task_getpgid, selinux_task_getpgid), |