This patch introduces the digest_query interface, which allows to write a query in the format ``<algo>-<digest>`` and to obtain all digest lists that include that digest.
Signed-off-by: Roberto Sassu roberto.sassu@huawei.com --- Documentation/security/digest_lists.rst | 7 ++ security/integrity/digest_lists/fs.c | 150 ++++++++++++++++++++++++ 2 files changed, 157 insertions(+)
diff --git a/Documentation/security/digest_lists.rst b/Documentation/security/digest_lists.rst index d83279046a55..f3900a6e92f6 100644 --- a/Documentation/security/digest_lists.rst +++ b/Documentation/security/digest_lists.rst @@ -690,3 +690,10 @@ removed.
``digest_label`` can be used to set a label to be applied to the next digest list (buffer) loaded ``through digest_list_add``. + + +``digest_query`` +~~~~~~~~~~~~~~~~ + +``digest_query``: allows to write a query in the format ``<algo>-<digest>`` +and to obtain all digest lists that include that digest. diff --git a/security/integrity/digest_lists/fs.c b/security/integrity/digest_lists/fs.c index f6e88fac27bc..bdfeb8797760 100644 --- a/security/integrity/digest_lists/fs.c +++ b/security/integrity/digest_lists/fs.c @@ -31,12 +31,17 @@
#define HDR_ASCII_FMT \ "actions: %d, version: %d, algo: %s, type: %d, modifiers: %d, count: %d, datalen: %d\n" +#define QUERY_RESULT_FMT \ + "%s (actions: %d): version: %d, algo: %s, type: %d, modifiers: %d, count: %d, datalen: %d\n" +#define QUERY_RESULT_DIGEST_LIST_FMT "%s (actions: %d): type: %d, size: %lld\n"
static struct dentry *digest_lists_dir; static struct dentry *digest_lists_loaded_dir; static struct dentry *digest_label_dentry; +static struct dentry *digest_query_dentry; static struct dentry *digest_list_add_dentry; static struct dentry *digest_list_del_dentry; +char digest_query[CRYPTO_MAX_ALG_NAME + 1 + IMA_MAX_DIGEST_SIZE * 2 + 1]; char digest_label[NAME_MAX + 1];
static int parse_digest_list_filename(const char *digest_list_filename, @@ -224,6 +229,83 @@ static const struct file_operations digest_list_ascii_ops = { .release = seq_release, };
+static void *digest_query_start(struct seq_file *m, loff_t *pos) +{ + struct digest_item *d; + u8 digest[IMA_MAX_DIGEST_SIZE]; + enum hash_algo algo; + loff_t count = 0; + enum compact_types type = 0; + struct digest_list_item_ref *ref; + int ret, refs; + + ret = parse_digest_list_filename(digest_query, digest, &algo); + if (ret < 0) + return NULL; + + for (type = 0; type < COMPACT__LAST; type++) { + d = digest_lookup(digest, algo, type, NULL, NULL); + if (!d) + continue; + + rcu_read_lock(); + for (ref = rcu_dereference(d->refs), refs = 0; + ref != NULL && !digest_list_ref_is_last(ref); + ref++, refs++) + ; + rcu_read_unlock(); + + count += refs; + + if (count > *pos) + break; + } + + if (type == COMPACT__LAST) + return NULL; + + return d->refs ? d->refs + (*pos - (count - refs)) : NULL; +} + +static void *digest_query_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct digest_list_item_ref *refs = (struct digest_list_item_ref *)v; + + refs++; + (*pos)++; + + return (refs->digest_list) ? refs : NULL; +} + +static void digest_query_stop(struct seq_file *m, void *v) +{ +} + +static int digest_query_show(struct seq_file *m, void *v) +{ + struct digest_list_item_ref *refs = (struct digest_list_item_ref *)v; + struct digest_list_item *digest_list = refs->digest_list; + struct compact_list_hdr *hdr; + + if (digest_list_ref_invalidated(refs)) + return 0; + + hdr = get_hdr_ref(refs); + + if (!refs->digest_offset) { + seq_printf(m, QUERY_RESULT_DIGEST_LIST_FMT, digest_list->label, + digest_list->actions, COMPACT_DIGEST_LIST, + digest_list->size); + return 0; + } + + seq_printf(m, QUERY_RESULT_FMT, digest_list->label, + digest_list->actions, hdr->version, + hash_algo_name[hdr->algo], hdr->type, hdr->modifiers, + hdr->count, hdr->datalen); + return 0; +} + static int digest_list_get_secfs_files(char *label, u8 *digest, enum hash_algo algo, enum ops op, struct dentry **dentry, @@ -492,6 +574,67 @@ static const struct file_operations digest_label_ops = { .llseek = generic_file_llseek, };
+static const struct seq_operations digest_query_seqops = { + .start = digest_query_start, + .next = digest_query_next, + .stop = digest_query_stop, + .show = digest_query_show, +}; + +/* + * digest_query_open: open to write a query or read the result. + */ +static int digest_query_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(0, &flags)) + return -EBUSY; + + if (file->f_flags & O_WRONLY) + return 0; + + return seq_open(file, &digest_query_seqops); +} + +/* + * digest_query_open: write digest query (<algo>-<digest>). + */ +static ssize_t digest_query_write(struct file *file, const char __user *buf, + size_t datalen, loff_t *ppos) +{ + int rc; + + if (datalen >= sizeof(digest_query)) + return -EINVAL; + + rc = copy_from_user(digest_query, buf, datalen); + if (rc < 0) + return rc; + + digest_query[datalen] = '\0'; + return datalen; +} + +/* + * digest_query_release - release the digest_query file + */ +static int digest_query_release(struct inode *inode, struct file *file) +{ + clear_bit(0, &flags); + + if (file->f_flags & O_WRONLY) + return 0; + + return seq_release(inode, file); +} + +static const struct file_operations digest_query_ops = { + .open = digest_query_open, + .write = digest_query_write, + .read = seq_read, + .release = digest_query_release, + .llseek = generic_file_llseek, +}; + static int __init digest_lists_fs_init(void) { digest_lists_dir = securityfs_create_dir("digest_lists", integrity_dir); @@ -521,8 +664,15 @@ static int __init digest_lists_fs_init(void) if (IS_ERR(digest_label_dentry)) goto out;
+ digest_query_dentry = securityfs_create_file("digest_query", 0600, + digest_lists_dir, NULL, + &digest_query_ops); + if (IS_ERR(digest_query_dentry)) + goto out; + return 0; out: + securityfs_remove(digest_query_dentry); securityfs_remove(digest_label_dentry); securityfs_remove(digest_list_del_dentry); securityfs_remove(digest_list_add_dentry);