diff options
Diffstat (limited to 'drivers/hid/bpf/hid_bpf_dispatch.c')
| -rw-r--r-- | drivers/hid/bpf/hid_bpf_dispatch.c | 193 |
1 files changed, 6 insertions, 187 deletions
diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c index 7216c3c7713d..06cc628e7bb4 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.c +++ b/drivers/hid/bpf/hid_bpf_dispatch.c @@ -3,7 +3,7 @@ /* * HID-BPF support for Linux * - * Copyright (c) 2022 Benjamin Tissoires + * Copyright (c) 2022-2024 Benjamin Tissoires */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt @@ -17,34 +17,11 @@ #include <linux/kfifo.h> #include <linux/minmax.h> #include <linux/module.h> -#include <linux/workqueue.h> #include "hid_bpf_dispatch.h" -#include "entrypoints/entrypoints.lskel.h" struct hid_ops *hid_ops; EXPORT_SYMBOL(hid_ops); -/** - * hid_bpf_device_event - Called whenever an event is coming in from the device - * - * @ctx: The HID-BPF context - * - * @return %0 on success and keep processing; a positive value to change the - * incoming size buffer; a negative error code to interrupt the processing - * of this event - * - * Declare an %fmod_ret tracing bpf program to this function and attach this - * program through hid_bpf_attach_prog() to have this helper called for - * any incoming event from the device itself. - * - * The function is called while on IRQ context, so we can not sleep. - */ -/* never used by the kernel but declared so we can load and attach a tracepoint */ -__weak noinline int hid_bpf_device_event(struct hid_bpf_ctx *ctx) -{ - return 0; -} - u8 * dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type, u8 *data, u32 *size, int interrupt) @@ -52,7 +29,6 @@ dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type struct hid_bpf_ctx_kern ctx_kern = { .ctx = { .hid = hdev, - .report_type = type, .allocated_size = hdev->bpf.allocated_data, .size = *size, }, @@ -86,11 +62,6 @@ dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type } rcu_read_unlock(); - ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_DEVICE_EVENT, &ctx_kern); - if (ret < 0) - return ERR_PTR(ret); - ret = ctx_kern.ctx.retval; - if (ret) { if (ret > ctx_kern.ctx.allocated_size) return ERR_PTR(-EINVAL); @@ -102,26 +73,6 @@ dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type } EXPORT_SYMBOL_GPL(dispatch_hid_bpf_device_event); -/** - * hid_bpf_rdesc_fixup - Called when the probe function parses the report - * descriptor of the HID device - * - * @ctx: The HID-BPF context - * - * @return 0 on success and keep processing; a positive value to change the - * incoming size buffer; a negative error code to interrupt the processing - * of this event - * - * Declare an %fmod_ret tracing bpf program to this function and attach this - * program through hid_bpf_attach_prog() to have this helper called before any - * parsing of the report descriptor by HID. - */ -/* never used by the kernel but declared so we can load and attach a tracepoint */ -__weak noinline int hid_bpf_rdesc_fixup(struct hid_bpf_ctx *ctx) -{ - return 0; -} - u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *size) { int ret; @@ -133,16 +84,16 @@ u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *s }, }; + if (!hdev->bpf.rdesc_ops) + goto ignore_bpf; + ctx_kern.data = kzalloc(ctx_kern.ctx.allocated_size, GFP_KERNEL); if (!ctx_kern.data) goto ignore_bpf; memcpy(ctx_kern.data, rdesc, min_t(unsigned int, *size, HID_MAX_DESCRIPTOR_SIZE)); - if (hdev->bpf.rdesc_ops) - ret = hdev->bpf.rdesc_ops->hid_rdesc_fixup(&ctx_kern.ctx); - else - ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_RDESC_FIXUP, &ctx_kern); + ret = hdev->bpf.rdesc_ops->hid_rdesc_fixup(&ctx_kern.ctx); if (ret < 0) goto ignore_bpf; @@ -242,39 +193,6 @@ int hid_bpf_reconnect(struct hid_device *hdev) return 0; } -static int do_hid_bpf_attach_prog(struct hid_device *hdev, int prog_fd, struct bpf_prog *prog, - __u32 flags) -{ - int fd, err, prog_type; - - prog_type = hid_bpf_get_prog_attach_type(prog); - if (prog_type < 0) - return prog_type; - - if (prog_type >= HID_BPF_PROG_TYPE_MAX) - return -EINVAL; - - if (prog_type == HID_BPF_PROG_TYPE_DEVICE_EVENT) { - err = hid_bpf_allocate_event_data(hdev); - if (err) - return err; - } - - fd = __hid_bpf_attach_prog(hdev, prog_type, prog_fd, prog, flags); - if (fd < 0) - return fd; - - if (prog_type == HID_BPF_PROG_TYPE_RDESC_FIXUP) { - err = hid_bpf_reconnect(hdev); - if (err) { - close_fd(fd); - return err; - } - } - - return fd; -} - /* Disables missing prototype warnings */ __bpf_kfunc_start_defs(); @@ -304,57 +222,6 @@ hid_bpf_get_data(struct hid_bpf_ctx *ctx, unsigned int offset, const size_t rdwr } /** - * hid_bpf_attach_prog - Attach the given @prog_fd to the given HID device - * - * @hid_id: the system unique identifier of the HID device - * @prog_fd: an fd in the user process representing the program to attach - * @flags: any logical OR combination of &enum hid_bpf_attach_flags - * - * @returns an fd of a bpf_link object on success (> %0), an error code otherwise. - * Closing this fd will detach the program from the HID device (unless the bpf_link - * is pinned to the BPF file system). - */ -/* called from syscall */ -__bpf_kfunc int -hid_bpf_attach_prog(unsigned int hid_id, int prog_fd, __u32 flags) -{ - struct hid_device *hdev; - struct bpf_prog *prog; - int err, fd; - - if ((flags & ~HID_BPF_FLAG_MASK)) - return -EINVAL; - - hdev = hid_get_device(hid_id); - if (IS_ERR(hdev)) - return PTR_ERR(hdev); - - /* - * take a ref on the prog itself, it will be released - * on errors or when it'll be detached - */ - prog = bpf_prog_get(prog_fd); - if (IS_ERR(prog)) { - err = PTR_ERR(prog); - goto out_dev_put; - } - - fd = do_hid_bpf_attach_prog(hdev, prog_fd, prog, flags); - if (fd < 0) { - err = fd; - goto out_prog_put; - } - - return fd; - - out_prog_put: - bpf_prog_put(prog); - out_dev_put: - hid_put_device(hdev); - return err; -} - -/** * hid_bpf_allocate_context - Allocate a context to the given HID device * * @hid_id: the system unique identifier of the HID device @@ -583,21 +450,8 @@ static const struct btf_kfunc_id_set hid_bpf_kfunc_set = { .set = &hid_bpf_kfunc_ids, }; -/* our HID-BPF entrypoints */ -BTF_SET8_START(hid_bpf_fmodret_ids) -BTF_ID_FLAGS(func, hid_bpf_device_event) -BTF_ID_FLAGS(func, hid_bpf_rdesc_fixup) -BTF_ID_FLAGS(func, __hid_bpf_tail_call) -BTF_SET8_END(hid_bpf_fmodret_ids) - -static const struct btf_kfunc_id_set hid_bpf_fmodret_set = { - .owner = THIS_MODULE, - .set = &hid_bpf_fmodret_ids, -}; - /* for syscall HID-BPF */ BTF_KFUNCS_START(hid_bpf_syscall_kfunc_ids) -BTF_ID_FLAGS(func, hid_bpf_attach_prog) BTF_ID_FLAGS(func, hid_bpf_allocate_context, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, hid_bpf_release_context, KF_RELEASE) BTF_ID_FLAGS(func, hid_bpf_hw_request) @@ -622,8 +476,6 @@ int hid_bpf_connect_device(struct hid_device *hdev) break; } } - if (rcu_dereference(hdev->bpf.progs[HID_BPF_PROG_TYPE_DEVICE_EVENT])) - need_to_allocate = true; rcu_read_unlock(); /* only allocate BPF data if there are programs attached */ @@ -650,14 +502,12 @@ void hid_bpf_destroy_device(struct hid_device *hdev) /* mark the device as destroyed in bpf so we don't reattach it */ hdev->bpf.destroyed = true; - __hid_bpf_destroy_device(hdev); __hid_bpf_ops_destroy_device(hdev); } EXPORT_SYMBOL_GPL(hid_bpf_destroy_device); void hid_bpf_device_init(struct hid_device *hdev) { - spin_lock_init(&hdev->bpf.progs_lock); INIT_LIST_HEAD(&hdev->bpf.prog_list); mutex_init(&hdev->bpf.prog_list_lock); } @@ -670,37 +520,15 @@ static int __init hid_bpf_init(void) /* Note: if we exit with an error any time here, we would entirely break HID, which * is probably not something we want. So we log an error and return success. * - * This is not a big deal: the syscall allowing to attach a BPF program to a HID device - * will not be available, so nobody will be able to use the functionality. + * This is not a big deal: nobody will be able to use the functionality. */ - err = register_btf_fmodret_id_set(&hid_bpf_fmodret_set); - if (err) { - pr_warn("error while registering fmodret entrypoints: %d", err); - return 0; - } - - err = hid_bpf_preload_skel(); - if (err) { - pr_warn("error while preloading HID BPF dispatcher: %d", err); - return 0; - } - - /* register tracing kfuncs after we are sure we can load our preloaded bpf program */ - err = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &hid_bpf_kfunc_set); - if (err) { - pr_warn("error while setting HID BPF tracing kfuncs: %d", err); - return 0; - } - - /* register struct_ops kfuncs after we are sure we can load our preloaded bpf program */ err = register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &hid_bpf_kfunc_set); if (err) { pr_warn("error while setting HID BPF tracing kfuncs: %d", err); return 0; } - /* register syscalls after we are sure we can load our preloaded bpf program */ err = register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &hid_bpf_syscall_kfunc_set); if (err) { pr_warn("error while setting HID BPF syscall kfuncs: %d", err); @@ -710,15 +538,6 @@ static int __init hid_bpf_init(void) return 0; } -static void __exit hid_bpf_exit(void) -{ - /* HID depends on us, so if we hit that code, we are guaranteed that hid - * has been removed and thus we do not need to clear the HID devices - */ - hid_bpf_free_links_and_skel(); -} - late_initcall(hid_bpf_init); -module_exit(hid_bpf_exit); MODULE_AUTHOR("Benjamin Tissoires"); MODULE_LICENSE("GPL"); |