Add the following scan callbacks:
```c
cl_engine_set_scan_callback(engine, &pre_hash_callback, CL_SCAN_CALLBACK_PRE_HASH);
cl_engine_set_scan_callback(engine, &pre_scan_callback, CL_SCAN_CALLBACK_PRE_SCAN);
cl_engine_set_scan_callback(engine, &post_scan_callback, CL_SCAN_CALLBACK_POST_SCAN);
cl_engine_set_scan_callback(engine, &alert_callback, CL_SCAN_CALLBACK_ALERT);
cl_engine_set_scan_callback(engine, &file_type_callback, CL_SCAN_CALLBACK_FILE_TYPE);
```
Each callback may alter scan behavior using the following return codes:
* CL_BREAK
Scan aborted by callback (the rest of the scan is skipped).
This does not mark the file as clean or infected, it just skips the rest of the scan.
* CL_SUCCESS / CL_CLEAN
File scan will continue.
This is different than CL_VERIFIED because it does not affect prior or future alerts.
Return CL_VERIFIED instead if you want to remove prior alerts for this layer and skip
the rest of the scan for this layer.
* CL_VIRUS
This means you don't trust the file. A new alert will be added.
For CL_SCAN_CALLBACK_ALERT: Means you agree with the alert (no extra alert needed).
* CL_VERIFIED
Layer explicitly trusted by the callback and previous alerts removed FOR THIS layer.
You might want to do this if you trust the hash or verified a digital signature.
The rest of the scan will be skipped FOR THIS layer.
For contained files, this does NOT mean that the parent or adjacent layers are trusted.
Each callback is given a pointer to the current scan layer from which
they can get previous layers, can get the the layer's fmap, and then
various attributes of the layer and of the fmap such as:
- layer recursion level
- layer object id
- layer file type
- layer attributes (was decerypted, normalized, embedded, or re-typed)
- layer last alert
- fmap name
- fmap hash (md5, sha1, or sha2-256)
- fmap data (pointer and size)
- fmap file descriptor, if any (fd, offset, size)
- fmap filepath, if any (filepath, offset, size)
To make this possible, this commits introduced a handful of new APIs to
query scan-layer details and fmap details:
- `cl_error_t cl_fmap_set_name(cl_fmap_t *map, const char *name);`
- `cl_error_t cl_fmap_get_name(cl_fmap_t *map, const char **name_out);`
- `cl_error_t cl_fmap_set_path(cl_fmap_t *map, const char *path);`
- `cl_error_t cl_fmap_get_path(cl_fmap_t *map, const char **path_out, size_t *offset_out, size_t *len_out);`
- `cl_error_t cl_fmap_get_fd(const cl_fmap_t *map, int *fd_out, size_t *offset_out, size_t *len_out);`
- `cl_error_t cl_fmap_get_size(const cl_fmap_t *map, size_t *size_out);`
- `cl_error_t cl_fmap_set_hash(const cl_fmap_t *map, const char *hash_alg, char hash);`
- `cl_error_t cl_fmap_have_hash(const cl_fmap_t *map, const char *hash_alg, bool *have_hash_out);`
- `cl_error_t cl_fmap_will_need_hash_later(const cl_fmap_t *map, const char *hash_alg);`
- `cl_error_t cl_fmap_get_hash(const cl_fmap_t *map, const char *hash_alg, const char **hash_out);`
- `cl_error_t cl_fmap_get_data(const cl_fmap_t *map, size_t offset, size_t len, const uint8_t **data_out, size_t *data_len_out);`
- `cl_error_t cl_scan_layer_get_fmap(cl_scan_layer_t *layer, cl_fmap_t **fmap_out);`
- `cl_error_t cl_scan_layer_get_parent_layer(cl_scan_layer_t *layer, cl_scan_layer_t **parent_layer_out);`
- `cl_error_t cl_scan_layer_get_type(cl_scan_layer_t *layer, const char **type_out);`
- `cl_error_t cl_scan_layer_get_recursion_level(cl_scan_layer_t *layer, uint32_t *recursion_level_out);`
- `cl_error_t cl_scan_layer_get_object_id(cl_scan_layer_t *layer, uint64_t *object_id_out);`
- `cl_error_t cl_scan_layer_get_last_alert(cl_scan_layer_t *layer, const char **alert_name_out);`
- `cl_error_t cl_scan_layer_get_attributes(cl_scan_layer_t *layer, uint32_t *attributes_out);`
This commit deprecates but does not remove the existing scan callbacks:
- `void cl_engine_set_clcb_pre_cache(struct cl_engine *engine, clcb_pre_cache callback);`
- `void cl_engine_set_clcb_file_inspection(struct cl_engine *engine, clcb_file_inspection callback);`
- `void cl_engine_set_clcb_pre_scan(struct cl_engine *engine, clcb_pre_scan callback);`
- `void cl_engine_set_clcb_post_scan(struct cl_engine *engine, clcb_post_scan callback);`
- `void cl_engine_set_clcb_virus_found(struct cl_engine *engine, clcb_virus_found callback);`
- `void cl_engine_set_clcb_hash(struct cl_engine *engine, clcb_hash callback);`
This commit also adds an interactive test program to demonstrate the callbacks.
See: `examples/ex_scan_callbacks.c`
CLAM-255
CLAM-2485
CLAM-2626
As of ClamAV 0.105, libjson-c is required.
There is also no option to disable libjson-c support.
This commit removes the dead code associated with the old build
option.
