ima: define new template ima-ng and template fields d-ng and n-ng
authorRoberto Sassu <roberto.sassu@polito.it>
Fri, 7 Jun 2013 10:16:32 +0000 (12:16 +0200)
committerMimi Zohar <zohar@linux.vnet.ibm.com>
Fri, 25 Oct 2013 21:17:05 +0000 (17:17 -0400)
This patch adds support for the new template 'ima-ng', whose format
is defined as 'd-ng|n-ng'.  These new field definitions remove the
size limitations of the original 'ima' template.  Further, the 'd-ng'
field prefixes the inode digest with the hash algorithim, when
displaying the new larger digest sizes.

Change log:
- scripts/Lindent fixes  - Mimi
- "always true comparison" - reported by Fengguang Wu, resolved Dmitry
- initialize hash_algo variable to HASH_ALGO__LAST
- always prefix digest with hash algorithm - Mimi

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
security/integrity/ima/ima_template.c
security/integrity/ima/ima_template_lib.c
security/integrity/ima/ima_template_lib.h

index 8100422643962ec3a1273711b1b722cfdb6ce123..bf38d1af3cfd7945b8bb61a2c1acda4047cdf744 100644 (file)
@@ -16,7 +16,8 @@
 #include "ima_template_lib.h"
 
 static struct ima_template_desc defined_templates[] = {
-       {.name = IMA_TEMPLATE_IMA_NAME,.fmt = IMA_TEMPLATE_IMA_FMT},
+       {.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT},
+       {.name = "ima-ng",.fmt = "d-ng|n-ng"},
 };
 
 static struct ima_template_field supported_fields[] = {
@@ -24,6 +25,10 @@ static struct ima_template_field supported_fields[] = {
         .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},
 };
 
 static struct ima_template_field *lookup_template_field(const char *field_id)
index e13fc7c04ebcd34950c854cede57dce02b6a9cf2..7d841448f2462ee976047a64a251896576ac8309 100644 (file)
  * File: ima_template_lib.c
  *      Library of supported template fields.
  */
+#include <crypto/hash_info.h>
+
 #include "ima_template_lib.h"
 
-enum data_formats { DATA_FMT_DIGEST = 0, DATA_FMT_EVENT_NAME, DATA_FMT_STRING };
+static bool ima_template_hash_algo_allowed(u8 algo)
+{
+       if (algo == HASH_ALGO_SHA1 || algo == HASH_ALGO_MD5)
+               return true;
+
+       return false;
+}
+
+enum data_formats {
+       DATA_FMT_DIGEST = 0,
+       DATA_FMT_DIGEST_WITH_ALGO,
+       DATA_FMT_EVENT_NAME,
+       DATA_FMT_STRING
+};
+
 static int ima_write_template_field_data(const void *data, const u32 datalen,
                                         enum data_formats datafmt,
                                         struct ima_field_data *field_data)
@@ -62,12 +78,22 @@ static void ima_show_template_data_ascii(struct seq_file *m,
                                         enum data_formats datafmt,
                                         struct ima_field_data *field_data)
 {
+       u8 *buf_ptr = field_data->data, buflen = field_data->len;
+
        switch (datafmt) {
+       case DATA_FMT_DIGEST_WITH_ALGO:
+               buf_ptr = strnchr(field_data->data, buflen, ':');
+               if (buf_ptr != field_data->data)
+                       seq_printf(m, "%s", field_data->data);
+
+               /* skip ':' and '\0' */
+               buf_ptr += 2;
+               buflen -= buf_ptr - field_data->data;
        case DATA_FMT_DIGEST:
-               ima_print_digest(m, field_data->data, field_data->len);
+               ima_print_digest(m, buf_ptr, buflen);
                break;
        case DATA_FMT_STRING:
-               seq_printf(m, "%s", field_data->data);
+               seq_printf(m, "%s", buf_ptr);
                break;
        default:
                break;
@@ -108,14 +134,59 @@ void ima_show_template_digest(struct seq_file *m, enum ima_show_type show,
        ima_show_template_field_data(m, show, DATA_FMT_DIGEST, field_data);
 }
 
+void ima_show_template_digest_ng(struct seq_file *m, enum ima_show_type show,
+                                struct ima_field_data *field_data)
+{
+       ima_show_template_field_data(m, show, DATA_FMT_DIGEST_WITH_ALGO,
+                                    field_data);
+}
+
 void ima_show_template_string(struct seq_file *m, enum ima_show_type show,
                              struct ima_field_data *field_data)
 {
        ima_show_template_field_data(m, show, DATA_FMT_STRING, field_data);
 }
 
+static int ima_eventdigest_init_common(u8 *digest, u32 digestsize, u8 hash_algo,
+                                      struct ima_field_data *field_data,
+                                      bool size_limit)
+{
+       /*
+        * digest formats:
+        *  - DATA_FMT_DIGEST: digest
+        *  - DATA_FMT_DIGEST_WITH_ALGO: [<hash algo>] + ':' + '\0' + digest,
+        *    where <hash algo> is provided if the hash algoritm is not
+        *    SHA1 or MD5
+        */
+       u8 buffer[CRYPTO_MAX_ALG_NAME + 2 + IMA_MAX_DIGEST_SIZE] = { 0 };
+       enum data_formats fmt = DATA_FMT_DIGEST;
+       u32 offset = 0;
+
+       if (!size_limit) {
+               fmt = DATA_FMT_DIGEST_WITH_ALGO;
+               if (hash_algo < HASH_ALGO__LAST)
+                       offset += snprintf(buffer, CRYPTO_MAX_ALG_NAME + 1,
+                                          "%s", hash_algo_name[hash_algo]);
+               buffer[offset] = ':';
+               offset += 2;
+       }
+
+       if (digest)
+               memcpy(buffer + offset, digest, digestsize);
+       else
+               /*
+                * If digest is NULL, the event being recorded is a violation.
+                * Make room for the digest by increasing the offset of
+                * IMA_DIGEST_SIZE.
+                */
+               offset += IMA_DIGEST_SIZE;
+
+       return ima_write_template_field_data(buffer, offset + digestsize,
+                                            fmt, field_data);
+}
+
 /*
- * This function writes the digest of an event.
+ * This function writes the digest of an event (with size limit).
  */
 int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
                         const unsigned char *filename,
@@ -125,8 +196,8 @@ int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
                struct ima_digest_data hdr;
                char digest[IMA_MAX_DIGEST_SIZE];
        } hash;
-       u8 *cur_digest = hash.hdr.digest;
-       u32 cur_digestsize = IMA_DIGEST_SIZE;
+       u8 *cur_digest = NULL;
+       u32 cur_digestsize = 0;
        struct inode *inode;
        int result;
 
@@ -135,7 +206,7 @@ int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
        if (!iint)              /* recording a violation. */
                goto out;
 
-       if (iint->ima_hash->algo == ima_hash_algo) {
+       if (ima_template_hash_algo_allowed(iint->ima_hash->algo)) {
                cur_digest = iint->ima_hash->digest;
                cur_digestsize = iint->ima_hash->length;
                goto out;
@@ -145,7 +216,8 @@ int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
                return -EINVAL;
 
        inode = file_inode(file);
-       hash.hdr.algo = ima_hash_algo;
+       hash.hdr.algo = ima_template_hash_algo_allowed(ima_hash_algo) ?
+           ima_hash_algo : HASH_ALGO_SHA1;
        result = ima_calc_file_hash(file, &hash.hdr);
        if (result) {
                integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode,
@@ -153,20 +225,46 @@ int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
                                    "failed", result, 0);
                return result;
        }
+       cur_digest = hash.hdr.digest;
+       cur_digestsize = hash.hdr.length;
 out:
-       return ima_write_template_field_data(cur_digest, cur_digestsize,
-                                            DATA_FMT_DIGEST, field_data);
+       return ima_eventdigest_init_common(cur_digest, cur_digestsize, -1,
+                                          field_data, true);
 }
 
 /*
- * This function writes the name of an event.
+ * This function writes the digest of an event (without size limit).
  */
-int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
-                      const unsigned char *filename,
-                      struct ima_field_data *field_data)
+int ima_eventdigest_ng_init(struct integrity_iint_cache *iint,
+                           struct file *file, const unsigned char *filename,
+                           struct ima_field_data *field_data)
+{
+       u8 *cur_digest = NULL, hash_algo = HASH_ALGO__LAST;
+       u32 cur_digestsize = 0;
+
+       /* If iint is NULL, we are recording a violation. */
+       if (!iint)
+               goto out;
+
+       cur_digest = iint->ima_hash->digest;
+       cur_digestsize = iint->ima_hash->length;
+
+       hash_algo = iint->ima_hash->algo;
+out:
+       return ima_eventdigest_init_common(cur_digest, cur_digestsize,
+                                          hash_algo, field_data, false);
+}
+
+static int ima_eventname_init_common(struct integrity_iint_cache *iint,
+                                    struct file *file,
+                                    const unsigned char *filename,
+                                    struct ima_field_data *field_data,
+                                    bool size_limit)
 {
        const char *cur_filename = NULL;
        u32 cur_filename_len = 0;
+       enum data_formats fmt = size_limit ?
+           DATA_FMT_EVENT_NAME : DATA_FMT_STRING;
 
        BUG_ON(filename == NULL && file == NULL);
 
@@ -174,7 +272,7 @@ int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
                cur_filename = filename;
                cur_filename_len = strlen(filename);
 
-               if (cur_filename_len <= IMA_EVENT_NAME_LEN_MAX)
+               if (!size_limit || cur_filename_len <= IMA_EVENT_NAME_LEN_MAX)
                        goto out;
        }
 
@@ -189,5 +287,27 @@ int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
                cur_filename_len = IMA_EVENT_NAME_LEN_MAX;
 out:
        return ima_write_template_field_data(cur_filename, cur_filename_len,
-                                            DATA_FMT_EVENT_NAME, field_data);
+                                            fmt, field_data);
+}
+
+/*
+ * This function writes the name of an event (with size limit).
+ */
+int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
+                      const unsigned char *filename,
+                      struct ima_field_data *field_data)
+{
+       return ima_eventname_init_common(iint, file, filename,
+                                        field_data, true);
+}
+
+/*
+ * This function writes the name of an event (without size limit).
+ */
+int ima_eventname_ng_init(struct integrity_iint_cache *iint, struct file *file,
+                         const unsigned char *filename,
+                         struct ima_field_data *field_data)
+{
+       return ima_eventname_init_common(iint, file, filename,
+                                        field_data, false);
 }
index 2cecc83a928d76112e9ed3bb84dc84e9312d953e..16c5e7810234d6e0f0b82cb4623a417e9f9cc22f 100644 (file)
@@ -20,6 +20,8 @@
 
 void ima_show_template_digest(struct seq_file *m, enum ima_show_type show,
                              struct ima_field_data *field_data);
+void ima_show_template_digest_ng(struct seq_file *m, enum ima_show_type show,
+                                struct ima_field_data *field_data);
 void ima_show_template_string(struct seq_file *m, enum ima_show_type show,
                              struct ima_field_data *field_data);
 int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
@@ -28,4 +30,10 @@ int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
 int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
                       const unsigned char *filename,
                       struct ima_field_data *field_data);
+int ima_eventdigest_ng_init(struct integrity_iint_cache *iint,
+                           struct file *file, const unsigned char *filename,
+                           struct ima_field_data *field_data);
+int ima_eventname_ng_init(struct integrity_iint_cache *iint, struct file *file,
+                         const unsigned char *filename,
+                         struct ima_field_data *field_data);
 #endif /* __LINUX_IMA_TEMPLATE_LIB_H */