// SPDX-License-Identifier: GPL-2.0 /* * Greybus manifest parsing * * Copyright 2014-2015 Google Inc. * Copyright 2014-2015 Linaro Ltd. */ #include <linux/greybus.h> static const char *get_descriptor_type_string(u8 type) { switch (type) { case GREYBUS_TYPE_INVALID: return "invalid"; case GREYBUS_TYPE_STRING: return "string"; case GREYBUS_TYPE_INTERFACE: return "interface"; case GREYBUS_TYPE_CPORT: return "cport"; case GREYBUS_TYPE_BUNDLE: return "bundle"; default: WARN_ON(1); return "unknown"; } } /* * We scan the manifest once to identify where all the descriptors * are. The result is a list of these manifest_desc structures. We * then pick through them for what we're looking for (starting with * the interface descriptor). As each is processed we remove it from * the list. When we're done the list should (probably) be empty. */ struct manifest_desc { struct list_head links; size_t size; void *data; enum greybus_descriptor_type type; }; static void release_manifest_descriptor(struct manifest_desc *descriptor) { list_del(&descriptor->links); kfree(descriptor); } static void release_manifest_descriptors(struct gb_interface *intf) { struct manifest_desc *descriptor; struct manifest_desc *next; list_for_each_entry_safe(descriptor, next, &intf->manifest_descs, links) release_manifest_descriptor(descriptor); } static void release_cport_descriptors(struct list_head *head, u8 bundle_id) { struct manifest_desc *desc, *tmp; struct greybus_descriptor_cport *desc_cport; list_for_each_entry_safe(desc, tmp, head, links) { desc_cport = desc->data; if (desc->type != GREYBUS_TYPE_CPORT) continue; if (desc_cport->bundle == bundle_id) release_manifest_descriptor(desc); } } static struct manifest_desc *get_next_bundle_desc(struct gb_interface *intf) { struct manifest_desc *descriptor; struct manifest_desc *next; list_for_each_entry_safe(descriptor, next, &intf->manifest_descs, links) if (descriptor->type == GREYBUS_TYPE_BUNDLE) return descriptor; return NULL; } /* * Validate the given descriptor. Its reported size must fit within * the number of bytes remaining, and it must have a recognized * type. Check that the reported size is at least as big as what * we expect to see. (It could be bigger, perhaps for a new version * of the format.) * * Returns the (non-zero) number of bytes consumed by the descriptor, * or a negative errno. */ static int identify_descriptor(struct gb_interface *intf, struct greybus_descriptor *desc, size_t size) { struct greybus_descriptor_header *desc_header = &desc->header; struct manifest_desc *descriptor; size_t desc_size; size_t expected_size; if (size < sizeof(*desc_header)) { dev_err(&intf->dev, "manifest too small (%zu < %zu)\n", size, sizeof(*desc_header)); return -EINVAL; /* Must at least have header */ } desc_size = le16_to_cpu(desc_header->size); if (desc_size > size) { dev_err(&intf->dev, "descriptor too big (%zu > %zu)\n", desc_size, size); return -EINVAL; } /* Descriptor needs to at least have a header */ expected_size = sizeof(*desc_header); switch (desc_header->type) { case GREYBUS_TYPE_STRING: expected_size += sizeof(struct greybus_descriptor_string); expected_size += desc->string.length; /* String descriptors are padded to 4 byte boundaries */ expected_size = ALIGN(expected_size, 4); break; case GREYBUS_TYPE_INTERFACE: expected_size += sizeof(struct greybus_descriptor_interface); break; case GREYBUS_TYPE_BUNDLE: expected_size += sizeof(struct greybus_descriptor_bundle); break; case GREYBUS_TYPE_CPORT: expected_size += sizeof(struct greybus_descriptor_cport); break; case GREYBUS_TYPE_INVALID: default: dev_err(&intf->dev, "invalid descriptor type (%u)\n", desc_header->type); return -EINVAL; } if (desc_size < expected_size) { dev_err(&intf->dev, "%s descriptor too small (%zu < %zu)\n", get_descriptor_type_string(desc_header->type), desc_size, expected_size); return -EINVAL; } /* Descriptor bigger than what we expect */ if (desc_size > expected_size) { dev_warn(&intf->dev, "%s descriptor size mismatch (want %zu got %zu)\n", get_descriptor_type_string(desc_header->type), expected_size, desc_size); } descriptor = kzalloc(sizeof(*descriptor), GFP_KERNEL); if (!descriptor) return -ENOMEM; descriptor->size = desc_size; descriptor->data = (char *)desc + sizeof(*desc_header); descriptor->type = desc_header->type; list_add_tail(&descriptor->links, &intf->manifest_descs); /* desc_size is positive and is known to fit in a signed int */ return desc_size; } /* * Find the string descriptor having the given id, validate it, and * allocate a duplicate copy of it. The duplicate has an extra byte * which guarantees the returned string is NUL-terminated. * * String index 0 is valid (it represents "no string"), and for * that a null pointer is returned. * * Otherwise returns a pointer to a newly-allocated copy of the * descriptor string, or an error-coded pointer on failure. */ static char *gb_string_get(struct gb_interface *intf, u8 string_id) { struct greybus_descriptor_string *desc_string; struct manifest_desc *descriptor; bool found = false; char *string; /* A zero string id means no string (but no error) */ if (!string_id) return NULL; list_for_each_entry(descriptor, &intf->manifest_descs, links) { if (descriptor->type != GREYBUS_TYPE_STRING) continue; desc_string = descriptor->data; if (desc_string->id == string_id) { found = true; break; } } if (!found) return ERR_PTR(-ENOENT); /* Allocate an extra byte so we can guarantee it's NUL-terminated */ string = kmemdup(&desc_string->string, desc_string->length + 1, GFP_KERNEL); if (!string) return ERR_PTR(-ENOMEM); string[desc_string->length] = '\0'; /* Ok we've used this string, so we're done with it */ release_manifest_descriptor(descriptor); return string; } /* * Find cport descriptors in the manifest associated with the given * bundle, and set up data structures for the functions that use * them. Returns the number of cports set up for the bundle, or 0 * if there is an error. */ static u32 gb_manifest_parse_cports(struct gb_bundle *bundle) { struct gb_interface *intf = bundle->intf; struct greybus_descriptor_cport *desc_cport; struct manifest_desc *desc, *next, *tmp; LIST_HEAD(list); u8 bundle_id = bundle->id; u16 cport_id; u32 count = 0; int i; /* Set up all cport descriptors associated with this bundle */ list_for_each_entry_safe(desc, next, &intf->manifest_descs, links) { if (desc->type != GREYBUS_TYPE_CPORT) continue; desc_cport = desc->data; if (desc_cport->bundle != bundle_id) continue; cport_id = le16_to_cpu(desc_cport->id); if (cport_id > CPORT_ID_MAX) goto exit; /* Nothing else should have its cport_id as control cport id */ if (cport_id == GB_CONTROL_CPORT_ID) { dev_err(&bundle->dev, "invalid cport id found (%02u)\n", cport_id); goto exit; } /* * Found one, move it to our temporary list after checking for * duplicates. */ list_for_each_entry(tmp, &list, links) { desc_cport = tmp->data; if (cport_id == le16_to_cpu(desc_cport->id)) { dev_err(&bundle->dev, "duplicate CPort %u found\n", cport_id); goto exit; } } list_move_tail(&desc->links, &list); count++; } if (!count) return 0; bundle->cport_desc = kcalloc(count, sizeof(*bundle->cport_desc), GFP_KERNEL); if (!bundle->cport_desc) goto exit; bundle->num_cports = count; i = 0; list_for_each_entry_safe(desc, next, &list, links) { desc_cport = desc->data; memcpy(&bundle->cport_desc[i++], desc_cport, sizeof(*desc_cport)); /* Release the cport descriptor */ release_manifest_descriptor(desc); } return count; exit: release_cport_descriptors(&list, bundle_id); /* * Free all cports for this bundle to avoid 'excess descriptors' * warnings. */ release_cport_descriptors(&intf->manifest_descs, bundle_id); return 0; /* Error; count should also be 0 */ } /* * Find bundle descriptors in the manifest and set up their data * structures. Returns the number of bundles set up for the * given interface. */ static u32 gb_manifest_parse_bundles(struct gb_interface *intf) { struct manifest_desc *desc; struct gb_bundle *bundle; struct gb_bundle *bundle_next; u32 count = 0; u8 bundle_id; u8 class; while ((desc = get_next_bundle_desc(intf))) { struct greybus_descriptor_bundle *desc_bundle; /* Found one. Set up its bundle structure*/ desc_bundle = desc->data; bundle_id = desc_bundle->id; class = desc_bundle->class; /* Done with this bundle descriptor */ release_manifest_descriptor(desc); /* Ignore any legacy control bundles */ if (bundle_id == GB_CONTROL_BUNDLE_ID) { dev_dbg(&intf->dev, "%s - ignoring control bundle\n", __func__); release_cport_descriptors(&intf->manifest_descs, bundle_id); continue; } /* Nothing else should have its class set to control class */ if (class == GREYBUS_CLASS_CONTROL) { dev_err(&intf->dev, "bundle %u cannot use control class\n", bundle_id); goto cleanup; } bundle = gb_bundle_create(intf, bundle_id, class); if (!bundle) goto cleanup; /* * Now go set up this bundle's functions and cports. * * A 'bundle' represents a device in greybus. It may require * multiple cports for its functioning. If we fail to setup any * cport of a bundle, we better reject the complete bundle as * the device may not be able to function properly then. * * But, failing to setup a cport of bundle X doesn't mean that * the device corresponding to bundle Y will not work properly. * Bundles should be treated as separate independent devices. * * While parsing manifest for an interface, treat bundles as * separate entities and don't reject entire interface and its * bundles on failing to initialize a cport. But make sure the * bundle which needs the cport, gets destroyed properly. */ if (!gb_manifest_parse_cports(bundle)) { gb_bundle_destroy(bundle); continue; } count++; } return count; cleanup: /* An error occurred; undo any changes we've made */ list_for_each_entry_safe(bundle, bundle_next, &intf->bundles, links) { gb_bundle_destroy(bundle); count--; } return 0; /* Error; count should also be 0 */ } static bool gb_manifest_parse_interface(struct gb_interface *intf, struct manifest_desc *interface_desc) { struct greybus_descriptor_interface *desc_intf = interface_desc->data; struct gb_control *control = intf->control; char *str; /* Handle the strings first--they can fail */ str = gb_string_get(intf, desc_intf->vendor_stringid); if (IS_ERR(str)) return false; control->vendor_string = str; str = gb_string_get(intf, desc_intf->product_stringid); if (IS_ERR(str)) goto out_free_vendor_string; control->product_string = str; /* Assign feature flags communicated via manifest */ intf->features = desc_intf->features; /* Release the interface descriptor, now that we're done with it */ release_manifest_descriptor(interface_desc); /* An interface must have at least one bundle descriptor */ if (!gb_manifest_parse_bundles(intf)) { dev_err(&intf->dev, "manifest bundle descriptors not valid\n"); goto out_err; } return true; out_err: kfree(control->product_string); control->product_string = NULL; out_free_vendor_string: kfree(control->vendor_string); control->vendor_string = NULL; return false; } /* * Parse a buffer containing an interface manifest. * * If we find anything wrong with the content/format of the buffer * we reject it. * * The first requirement is that the manifest's version is * one we can parse. * * We make an initial pass through the buffer and identify all of * the descriptors it contains, keeping track for each its type * and the location size of its data in the buffer. * * Next we scan the descriptors, looking for an interface descriptor; * there must be exactly one of those. When found, we record the * information it contains, and then remove that descriptor (and any * string descriptors it refers to) from further consideration. * * After that we look for the interface's bundles--there must be at * least one of those. * * Returns true if parsing was successful, false otherwise. */ bool gb_manifest_parse(struct gb_interface *intf, void *data, size_t size) { struct greybus_manifest *manifest; struct greybus_manifest_header *header; struct greybus_descriptor *desc; struct manifest_desc *descriptor; struct manifest_desc *interface_desc = NULL; u16 manifest_size; u32 found = 0; bool result; /* Manifest descriptor list should be empty here */ if (WARN_ON(!list_empty(&intf->manifest_descs))) return false; /* we have to have at _least_ the manifest header */ if (size < sizeof(*header)) { dev_err(&intf->dev, "short manifest (%zu < %zu)\n", size, sizeof(*header)); return false; } /* Make sure the size is right */ manifest = data; header = &manifest->header; manifest_size = le16_to_cpu(header->size); if (manifest_size != size) { dev_err(&intf->dev, "manifest size mismatch (%zu != %u)\n", size, manifest_size); return false; } /* Validate major/minor number */ if (header->version_major > GREYBUS_VERSION_MAJOR) { dev_err(&intf->dev, "manifest version too new (%u.%u > %u.%u)\n", header->version_major, header->version_minor, GREYBUS_VERSION_MAJOR, GREYBUS_VERSION_MINOR); return false; } /* OK, find all the descriptors */ desc = manifest->descriptors; size -= sizeof(*header); while (size) { int desc_size; desc_size = identify_descriptor(intf, desc, size); if (desc_size < 0) { result = false; goto out; } desc = (struct greybus_descriptor *)((char *)desc + desc_size); size -= desc_size; } /* There must be a single interface descriptor */ list_for_each_entry(descriptor, &intf->manifest_descs, links) { if (descriptor->type == GREYBUS_TYPE_INTERFACE) if (!found++) interface_desc = descriptor; } if (found != 1) { dev_err(&intf->dev, "manifest must have 1 interface descriptor (%u found)\n", found); result = false; goto out; } /* Parse the manifest, starting with the interface descriptor */ result = gb_manifest_parse_interface(intf, interface_desc); /* * We really should have no remaining descriptors, but we * don't know what newer format manifests might leave. */ if (result && !list_empty(&intf->manifest_descs)) dev_info(&intf->dev, "excess descriptors in interface manifest\n"); out: release_manifest_descriptors(intf); return result; }