diff options
Diffstat (limited to 'security/integrity/ima/ima_template.c')
| -rw-r--r-- | security/integrity/ima/ima_template.c | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c new file mode 100644 index 000000000000..635695f6a185 --- /dev/null +++ b/security/integrity/ima/ima_template.c @@ -0,0 +1,187 @@ +/* + * Copyright (C) 2013 Politecnico di Torino, Italy + * TORSEC group -- http://security.polito.it + * + * Author: Roberto Sassu <roberto.sassu@polito.it> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation, version 2 of the + * License. + * + * File: ima_template.c + * Helpers to manage template descriptors. + */ +#include <crypto/hash_info.h> + +#include "ima.h" +#include "ima_template_lib.h" + +static struct ima_template_desc defined_templates[] = { + {.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT}, + {.name = "ima-ng",.fmt = "d-ng|n-ng"}, + {.name = "ima-sig",.fmt = "d-ng|n-ng|sig"}, +}; + +static struct ima_template_field supported_fields[] = { + {.field_id = "d",.field_init = ima_eventdigest_init, + .field_show = ima_show_template_digest}, + {.field_id = "n",.field_init = ima_eventname_init, + .field_show = ima_show_template_string}, + {.field_id = "d-ng",.field_init = ima_eventdigest_ng_init, + .field_show = ima_show_template_digest_ng}, + {.field_id = "n-ng",.field_init = ima_eventname_ng_init, + .field_show = ima_show_template_string}, + {.field_id = "sig",.field_init = ima_eventsig_init, + .field_show = ima_show_template_sig}, +}; + +static struct ima_template_desc *ima_template; +static struct ima_template_desc *lookup_template_desc(const char *name); + +static int __init ima_template_setup(char *str) +{ + struct ima_template_desc *template_desc; + int template_len = strlen(str); + + /* + * Verify that a template with the supplied name exists. + * If not, use CONFIG_IMA_DEFAULT_TEMPLATE. + */ + template_desc = lookup_template_desc(str); + if (!template_desc) + return 1; + + /* + * Verify whether the current hash algorithm is supported + * by the 'ima' template. + */ + if (template_len == 3 && strcmp(str, IMA_TEMPLATE_IMA_NAME) == 0 && + ima_hash_algo != HASH_ALGO_SHA1 && ima_hash_algo != HASH_ALGO_MD5) { + pr_err("IMA: template does not support hash alg\n"); + return 1; + } + + ima_template = template_desc; + return 1; +} +__setup("ima_template=", ima_template_setup); + +static struct ima_template_desc *lookup_template_desc(const char *name) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(defined_templates); i++) { + if (strcmp(defined_templates[i].name, name) == 0) + return defined_templates + i; + } + + return NULL; +} + +static struct ima_template_field *lookup_template_field(const char *field_id) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(supported_fields); i++) + if (strncmp(supported_fields[i].field_id, field_id, + IMA_TEMPLATE_FIELD_ID_MAX_LEN) == 0) + return &supported_fields[i]; + return NULL; +} + +static int template_fmt_size(const char *template_fmt) +{ + char c; + int template_fmt_len = strlen(template_fmt); + int i = 0, j = 0; + + while (i < template_fmt_len) { + c = template_fmt[i]; + if (c == '|') + j++; + i++; + } + + return j + 1; +} + +static int template_desc_init_fields(const char *template_fmt, + struct ima_template_field ***fields, + int *num_fields) +{ + char *c, *template_fmt_copy, *template_fmt_ptr; + int template_num_fields = template_fmt_size(template_fmt); + int i, result = 0; + + if (template_num_fields > IMA_TEMPLATE_NUM_FIELDS_MAX) + return -EINVAL; + + /* copying is needed as strsep() modifies the original buffer */ + template_fmt_copy = kstrdup(template_fmt, GFP_KERNEL); + if (template_fmt_copy == NULL) + return -ENOMEM; + + *fields = kzalloc(template_num_fields * sizeof(*fields), GFP_KERNEL); + if (*fields == NULL) { + result = -ENOMEM; + goto out; + } + + template_fmt_ptr = template_fmt_copy; + for (i = 0; (c = strsep(&template_fmt_ptr, "|")) != NULL && + i < template_num_fields; i++) { + struct ima_template_field *f = lookup_template_field(c); + + if (!f) { + result = -ENOENT; + goto out; + } + (*fields)[i] = f; + } + *num_fields = i; +out: + if (result < 0) { + kfree(*fields); + *fields = NULL; + } + kfree(template_fmt_copy); + return result; +} + +static int init_defined_templates(void) +{ + int i = 0; + int result = 0; + + /* Init defined templates. */ + for (i = 0; i < ARRAY_SIZE(defined_templates); i++) { + struct ima_template_desc *template = &defined_templates[i]; + + result = template_desc_init_fields(template->fmt, + &(template->fields), + &(template->num_fields)); + if (result < 0) + return result; + } + return result; +} + +struct ima_template_desc *ima_template_desc_current(void) +{ + if (!ima_template) + ima_template = + lookup_template_desc(CONFIG_IMA_DEFAULT_TEMPLATE); + return ima_template; +} + +int ima_init_template(void) +{ + int result; + + result = init_defined_templates(); + if (result < 0) + return result; + + return 0; +} |