From a1db74209483a24c861c848b4bb79a4d945ef6fa Mon Sep 17 00:00:00 2001 From: Mimi Zohar Date: Wed, 30 Dec 2015 07:35:30 -0500 Subject: module: replace copy_module_from_fd with kernel version Replace copy_module_from_fd() with kernel_read_file_from_fd(). Although none of the upstreamed LSMs define a kernel_module_from_file hook, IMA is called, based on policy, to prevent unsigned kernel modules from being loaded by the original kernel module syscall and to measure/appraise signed kernel modules. The security function security_kernel_module_from_file() was called prior to reading a kernel module. Preventing unsigned kernel modules from being loaded by the original kernel module syscall remains on the pre-read kernel_read_file() security hook. Instead of reading the kernel module twice, once for measuring/appraising and again for loading the kernel module, the signature validation is moved to the kernel_post_read_file() security hook. This patch removes the security_kernel_module_from_file() hook and security call. Signed-off-by: Mimi Zohar Acked-by: Kees Cook Acked-by: Luis R. Rodriguez Cc: Rusty Russell --- security/integrity/ima/ima_main.c | 35 +++++++++++++---------------------- 1 file changed, 13 insertions(+), 22 deletions(-) (limited to 'security/integrity') diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index bbb80df..5da0b9c 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -316,28 +316,6 @@ int ima_file_check(struct file *file, int mask, int opened) EXPORT_SYMBOL_GPL(ima_file_check); /** - * ima_module_check - based on policy, collect/store/appraise measurement. - * @file: pointer to the file to be measured/appraised - * - * Measure/appraise kernel modules based on policy. - * - * On success return 0. On integrity appraisal error, assuming the file - * is in policy and IMA-appraisal is in enforcing mode, return -EACCES. - */ -int ima_module_check(struct file *file) -{ - if (!file) { -#ifndef CONFIG_MODULE_SIG_FORCE - if ((ima_appraise & IMA_APPRAISE_MODULES) && - (ima_appraise & IMA_APPRAISE_ENFORCE)) - return -EACCES; /* INTEGRITY_UNKNOWN */ -#endif - return 0; /* We rely on module signature checking */ - } - return process_measurement(file, NULL, 0, MAY_EXEC, MODULE_CHECK, 0); -} - -/** * ima_read_file - pre-measure/appraise hook decision based on policy * @file: pointer to the file to be measured/appraised/audit * @read_id: caller identifier @@ -350,6 +328,14 @@ int ima_module_check(struct file *file) */ int ima_read_file(struct file *file, enum kernel_read_file_id read_id) { + if (!file && read_id == READING_MODULE) { +#ifndef CONFIG_MODULE_SIG_FORCE + if ((ima_appraise & IMA_APPRAISE_MODULES) && + (ima_appraise & IMA_APPRAISE_ENFORCE)) + return -EACCES; /* INTEGRITY_UNKNOWN */ +#endif + return 0; /* We rely on module signature checking */ + } return 0; } @@ -378,6 +364,9 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size, return 0; } + if (!file && read_id == READING_MODULE) /* MODULE_SIG_FORCE enabled */ + return 0; + if (!file || !buf || size == 0) { /* should never happen */ if (ima_appraise & IMA_APPRAISE_ENFORCE) return -EACCES; @@ -386,6 +375,8 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size, if (read_id == READING_FIRMWARE) func = FIRMWARE_CHECK; + else if (read_id == READING_MODULE) + func = MODULE_CHECK; return process_measurement(file, buf, size, MAY_READ, func, 0); } -- cgit v1.1