diff options
Diffstat (limited to 'security/integrity/ima/ima_main.c')
| -rw-r--r-- | security/integrity/ima/ima_main.c | 68 |
1 files changed, 50 insertions, 18 deletions
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index cdd225f65a62..5770cf691912 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -235,7 +235,8 @@ static void ima_file_free(struct file *file) static int process_measurement(struct file *file, const struct cred *cred, struct lsm_prop *prop, char *buf, loff_t size, - int mask, enum ima_hooks func) + int mask, enum ima_hooks func, + enum kernel_read_file_id read_id) { struct inode *real_inode, *inode = file_inode(file); struct ima_iint_cache *iint = NULL; @@ -406,6 +407,12 @@ static int process_measurement(struct file *file, const struct cred *cred, if (rc != 0 && rc != -EBADF && rc != -EINVAL) goto out_locked; + /* Defer measuring/appraising kernel modules to READING_MODULE */ + if (read_id == READING_MODULE_COMPRESSED) { + must_appraise = 0; + goto out_locked; + } + if (!pathbuf) /* ima_rdwr_violation possibly pre-fetched */ pathname = ima_d_path(&file->f_path, &pathbuf, filename); @@ -486,14 +493,14 @@ static int ima_file_mmap(struct file *file, unsigned long reqprot, if (reqprot & PROT_EXEC) { ret = process_measurement(file, current_cred(), &prop, NULL, - 0, MAY_EXEC, MMAP_CHECK_REQPROT); + 0, MAY_EXEC, MMAP_CHECK_REQPROT, 0); if (ret) return ret; } if (prot & PROT_EXEC) return process_measurement(file, current_cred(), &prop, NULL, - 0, MAY_EXEC, MMAP_CHECK); + 0, MAY_EXEC, MMAP_CHECK, 0); return 0; } @@ -573,18 +580,41 @@ static int ima_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot, */ static int ima_bprm_check(struct linux_binprm *bprm) { - int ret; struct lsm_prop prop; security_current_getlsmprop_subj(&prop); - ret = process_measurement(bprm->file, current_cred(), - &prop, NULL, 0, MAY_EXEC, BPRM_CHECK); - if (ret) - return ret; - - security_cred_getlsmprop(bprm->cred, &prop); - return process_measurement(bprm->file, bprm->cred, &prop, NULL, 0, - MAY_EXEC, CREDS_CHECK); + return process_measurement(bprm->file, current_cred(), + &prop, NULL, 0, MAY_EXEC, BPRM_CHECK, 0); +} + +/** + * ima_creds_check - based on policy, collect/store measurement. + * @bprm: contains the linux_binprm structure + * @file: contains the file descriptor of the binary being executed + * + * The OS protects against an executable file, already open for write, + * from being executed in deny_write_access() and an executable file, + * already open for execute, from being modified in get_write_access(). + * So we can be certain that what we verify and measure here is actually + * what is being executed. + * + * The difference from ima_bprm_check() is that ima_creds_check() is invoked + * only after determining the final binary to be executed without interpreter, + * and not when searching for intermediate binaries. The reason is that since + * commit 56305aa9b6fab ("exec: Compute file based creds only once"), the + * credentials to be applied to the process are calculated only at that stage + * (bprm_creds_from_file security hook instead of bprm_check_security). + * + * On success return 0. On integrity appraisal error, assuming the file + * is in policy and IMA-appraisal is in enforcing mode, return -EACCES. + */ +static int ima_creds_check(struct linux_binprm *bprm, const struct file *file) +{ + struct lsm_prop prop; + + security_current_getlsmprop_subj(&prop); + return process_measurement((struct file *)file, bprm->cred, &prop, NULL, + 0, MAY_EXEC, CREDS_CHECK, 0); } /** @@ -632,7 +662,7 @@ static int ima_file_check(struct file *file, int mask) security_current_getlsmprop_subj(&prop); return process_measurement(file, current_cred(), &prop, NULL, 0, mask & (MAY_READ | MAY_WRITE | MAY_EXEC | - MAY_APPEND), FILE_CHECK); + MAY_APPEND), FILE_CHECK, 0); } static int __ima_inode_hash(struct inode *inode, struct file *file, char *buf, @@ -851,12 +881,13 @@ static int ima_read_file(struct file *file, enum kernel_read_file_id read_id, func = read_idmap[read_id] ?: FILE_CHECK; security_current_getlsmprop_subj(&prop); return process_measurement(file, current_cred(), &prop, NULL, 0, - MAY_READ, func); + MAY_READ, func, 0); } const int read_idmap[READING_MAX_ID] = { [READING_FIRMWARE] = FIRMWARE_CHECK, [READING_MODULE] = MODULE_CHECK, + [READING_MODULE_COMPRESSED] = MODULE_CHECK, [READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK, [READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK, [READING_POLICY] = POLICY_CHECK @@ -894,7 +925,7 @@ static int ima_post_read_file(struct file *file, char *buf, loff_t size, func = read_idmap[read_id] ?: FILE_CHECK; security_current_getlsmprop_subj(&prop); return process_measurement(file, current_cred(), &prop, buf, size, - MAY_READ, func); + MAY_READ, func, read_id); } /** @@ -1242,6 +1273,7 @@ static int __init init_ima(void) static struct security_hook_list ima_hooks[] __ro_after_init = { LSM_HOOK_INIT(bprm_check_security, ima_bprm_check), LSM_HOOK_INIT(bprm_creds_for_exec, ima_bprm_creds_for_exec), + LSM_HOOK_INIT(bprm_creds_from_file, ima_creds_check), LSM_HOOK_INIT(file_post_open, ima_file_check), LSM_HOOK_INIT(inode_post_create_tmpfile, ima_post_create_tmpfile), LSM_HOOK_INIT(file_release, ima_file_free), @@ -1279,10 +1311,10 @@ struct lsm_blob_sizes ima_blob_sizes __ro_after_init = { }; DEFINE_LSM(ima) = { - .name = "ima", + .id = &ima_lsmid, .init = init_ima_lsm, .order = LSM_ORDER_LAST, .blobs = &ima_blob_sizes, + /* Start IMA after the TPM is available */ + .initcall_late = init_ima, }; - -late_initcall(init_ima); /* Start IMA after the TPM is available */ |