diff --git a/include/linux/ima.h b/include/linux/ima.h index 31ef6c3c3207..0f9af283cbc8 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -256,4 +256,14 @@ static inline bool ima_appraise_signature(enum kernel_read_file_id func) return false; } #endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */ + +#if defined(CONFIG_IMA) && defined(CONFIG_INTEGRITY_ASYMMETRIC_KEYS) +extern int ima_kernel_module_request(char *kmod_name); +#else +static inline int ima_kernel_module_request(char *kmod_name) +{ + return 0; +} + +#endif #endif /* _LINUX_IMA_H */ diff --git a/include/linux/integrity.h b/include/linux/integrity.h index 2ea0f2f65ab6..ef0f63ef5ebc 100644 --- a/include/linux/integrity.h +++ b/include/linux/integrity.h @@ -42,17 +42,4 @@ static inline void integrity_load_keys(void) } #endif /* CONFIG_INTEGRITY */ -#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS - -extern int integrity_kernel_module_request(char *kmod_name); - -#else - -static inline int integrity_kernel_module_request(char *kmod_name) -{ - return 0; -} - -#endif /* CONFIG_INTEGRITY_ASYMMETRIC_KEYS */ - #endif /* _LINUX_INTEGRITY_H */ diff --git a/security/integrity/digsig_asymmetric.c b/security/integrity/digsig_asymmetric.c index 895f4b9ce8c6..de603cf42ac7 100644 --- a/security/integrity/digsig_asymmetric.c +++ b/security/integrity/digsig_asymmetric.c @@ -132,26 +132,3 @@ out: pr_debug("%s() = %d\n", __func__, ret); return ret; } - -/** - * integrity_kernel_module_request - prevent crypto-pkcs1pad(rsa,*) requests - * @kmod_name: kernel module name - * - * We have situation, when public_key_verify_signature() in case of RSA - * algorithm use alg_name to store internal information in order to - * construct an algorithm on the fly, but crypto_larval_lookup() will try - * to use alg_name in order to load kernel module with same name. - * Since we don't have any real "crypto-pkcs1pad(rsa,*)" kernel modules, - * we are safe to fail such module request from crypto_larval_lookup(). - * - * In this way we prevent modprobe execution during digsig verification - * and avoid possible deadlock if modprobe and/or it's dependencies - * also signed with digsig. - */ -int integrity_kernel_module_request(char *kmod_name) -{ - if (strncmp(kmod_name, "crypto-pkcs1pad(rsa,", 20) == 0) - return -EINVAL; - - return 0; -} diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 02021ee467d3..3891b83efdb3 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -1091,6 +1091,39 @@ int ima_measure_critical_data(const char *event_label, } EXPORT_SYMBOL_GPL(ima_measure_critical_data); +#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS + +/** + * ima_kernel_module_request - Prevent crypto-pkcs1pad(rsa,*) requests + * @kmod_name: kernel module name + * + * Avoid a verification loop where verifying the signature of the modprobe + * binary requires executing modprobe itself. Since the modprobe iint->mutex + * is already held when the signature verification is performed, a deadlock + * occurs as soon as modprobe is executed within the critical region, since + * the same lock cannot be taken again. + * + * This happens when public_key_verify_signature(), in case of RSA algorithm, + * use alg_name to store internal information in order to construct an + * algorithm on the fly, but crypto_larval_lookup() will try to use alg_name + * in order to load a kernel module with same name. + * + * Since we don't have any real "crypto-pkcs1pad(rsa,*)" kernel modules, + * we are safe to fail such module request from crypto_larval_lookup(), and + * avoid the verification loop. + * + * Return: Zero if it is safe to load the kernel module, -EINVAL otherwise. + */ +int ima_kernel_module_request(char *kmod_name) +{ + if (strncmp(kmod_name, "crypto-pkcs1pad(rsa,", 20) == 0) + return -EINVAL; + + return 0; +} + +#endif /* CONFIG_INTEGRITY_ASYMMETRIC_KEYS */ + static int __init init_ima(void) { int error; diff --git a/security/security.c b/security/security.c index 6c23c620e3c1..bc3c6790aeaf 100644 --- a/security/security.c +++ b/security/security.c @@ -3249,7 +3249,7 @@ int security_kernel_module_request(char *kmod_name) ret = call_int_hook(kernel_module_request, 0, kmod_name); if (ret) return ret; - return integrity_kernel_module_request(kmod_name); + return ima_kernel_module_request(kmod_name); } /**