diff options
-rw-r--r-- | include/linux/bpf.h | 13 | ||||
-rw-r--r-- | include/linux/bpf_types.h | 1 | ||||
-rw-r--r-- | include/linux/bpf_verifier.h | 4 | ||||
-rw-r--r-- | include/uapi/linux/bpf.h | 84 | ||||
-rw-r--r-- | kernel/bpf/Makefile | 2 | ||||
-rw-r--r-- | kernel/bpf/helpers.c | 10 | ||||
-rw-r--r-- | kernel/bpf/ringbuf.c | 501 | ||||
-rw-r--r-- | kernel/bpf/syscall.c | 12 | ||||
-rw-r--r-- | kernel/bpf/verifier.c | 195 | ||||
-rw-r--r-- | kernel/trace/bpf_trace.c | 10 | ||||
-rw-r--r-- | tools/include/uapi/linux/bpf.h | 84 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/verifier/and.c | 4 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/verifier/array_access.c | 4 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/verifier/bounds.c | 6 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/verifier/calls.c | 2 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/verifier/direct_value_access.c | 4 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/verifier/helper_access_var_len.c | 2 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/verifier/helper_value_access.c | 6 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/verifier/value_ptr_arith.c | 8 |
19 files changed, 882 insertions, 70 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index efe8836b5c48..e5884f7f801c 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -90,6 +90,8 @@ struct bpf_map_ops { int (*map_direct_value_meta)(const struct bpf_map *map, u64 imm, u32 *off); int (*map_mmap)(struct bpf_map *map, struct vm_area_struct *vma); + __poll_t (*map_poll)(struct bpf_map *map, struct file *filp, + struct poll_table_struct *pts); }; struct bpf_map_memory { @@ -244,6 +246,9 @@ enum bpf_arg_type { ARG_PTR_TO_LONG, /* pointer to long */ ARG_PTR_TO_SOCKET, /* pointer to bpf_sock (fullsock) */ ARG_PTR_TO_BTF_ID, /* pointer to in-kernel struct */ + ARG_PTR_TO_ALLOC_MEM, /* pointer to dynamically allocated memory */ + ARG_PTR_TO_ALLOC_MEM_OR_NULL, /* pointer to dynamically allocated memory or NULL */ + ARG_CONST_ALLOC_SIZE_OR_ZERO, /* number of allocated bytes requested */ }; /* type of values returned from helper functions */ @@ -255,6 +260,7 @@ enum bpf_return_type { RET_PTR_TO_SOCKET_OR_NULL, /* returns a pointer to a socket or NULL */ RET_PTR_TO_TCP_SOCK_OR_NULL, /* returns a pointer to a tcp_sock or NULL */ RET_PTR_TO_SOCK_COMMON_OR_NULL, /* returns a pointer to a sock_common or NULL */ + RET_PTR_TO_ALLOC_MEM_OR_NULL, /* returns a pointer to dynamically allocated memory or NULL */ }; /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs @@ -322,6 +328,8 @@ enum bpf_reg_type { PTR_TO_XDP_SOCK, /* reg points to struct xdp_sock */ PTR_TO_BTF_ID, /* reg points to kernel struct */ PTR_TO_BTF_ID_OR_NULL, /* reg points to kernel struct or NULL */ + PTR_TO_MEM, /* reg points to valid memory region */ + PTR_TO_MEM_OR_NULL, /* reg points to valid memory region or NULL */ }; /* The information passed from prog-specific *_is_valid_access @@ -1611,6 +1619,11 @@ extern const struct bpf_func_proto bpf_tcp_sock_proto; extern const struct bpf_func_proto bpf_jiffies64_proto; extern const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto; extern const struct bpf_func_proto bpf_event_output_data_proto; +extern const struct bpf_func_proto bpf_ringbuf_output_proto; +extern const struct bpf_func_proto bpf_ringbuf_reserve_proto; +extern const struct bpf_func_proto bpf_ringbuf_submit_proto; +extern const struct bpf_func_proto bpf_ringbuf_discard_proto; +extern const struct bpf_func_proto bpf_ringbuf_query_proto; const struct bpf_func_proto *bpf_tracing_func_proto( enum bpf_func_id func_id, const struct bpf_prog *prog); diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index 29d22752fc87..fa8e1b552acd 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -118,6 +118,7 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_STACK, stack_map_ops) #if defined(CONFIG_BPF_JIT) BPF_MAP_TYPE(BPF_MAP_TYPE_STRUCT_OPS, bpf_struct_ops_map_ops) #endif +BPF_MAP_TYPE(BPF_MAP_TYPE_RINGBUF, ringbuf_map_ops) BPF_LINK_TYPE(BPF_LINK_TYPE_RAW_TRACEPOINT, raw_tracepoint) BPF_LINK_TYPE(BPF_LINK_TYPE_TRACING, tracing) diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index ea833087e853..ca08db4ffb5f 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -54,6 +54,8 @@ struct bpf_reg_state { u32 btf_id; /* for PTR_TO_BTF_ID */ + u32 mem_size; /* for PTR_TO_MEM | PTR_TO_MEM_OR_NULL */ + /* Max size from any of the above. */ unsigned long raw; }; @@ -63,6 +65,8 @@ struct bpf_reg_state { * offset, so they can share range knowledge. * For PTR_TO_MAP_VALUE_OR_NULL this is used to share which map value we * came from, when one is tested for != NULL. + * For PTR_TO_MEM_OR_NULL this is used to identify memory allocation + * for the purpose of tracking that it's freed. * For PTR_TO_SOCKET this is used to share which pointers retain the * same reference to the socket, to determine proper reference freeing. */ diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 54b93f8b49b8..974ca6e948e3 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -147,6 +147,7 @@ enum bpf_map_type { BPF_MAP_TYPE_SK_STORAGE, BPF_MAP_TYPE_DEVMAP_HASH, BPF_MAP_TYPE_STRUCT_OPS, + BPF_MAP_TYPE_RINGBUF, }; /* Note that tracing related programs such as @@ -3157,6 +3158,59 @@ union bpf_attr { * **bpf_sk_cgroup_id**\ (). * Return * The id is returned or 0 in case the id could not be retrieved. + * + * void *bpf_ringbuf_output(void *ringbuf, void *data, u64 size, u64 flags) + * Description + * Copy *size* bytes from *data* into a ring buffer *ringbuf*. + * If BPF_RB_NO_WAKEUP is specified in *flags*, no notification of + * new data availability is sent. + * IF BPF_RB_FORCE_WAKEUP is specified in *flags*, notification of + * new data availability is sent unconditionally. + * Return + * 0, on success; + * < 0, on error. + * + * void *bpf_ringbuf_reserve(void *ringbuf, u64 size, u64 flags) + * Description + * Reserve *size* bytes of payload in a ring buffer *ringbuf*. + * Return + * Valid pointer with *size* bytes of memory available; NULL, + * otherwise. + * + * void bpf_ringbuf_submit(void *data, u64 flags) + * Description + * Submit reserved ring buffer sample, pointed to by *data*. + * If BPF_RB_NO_WAKEUP is specified in *flags*, no notification of + * new data availability is sent. + * IF BPF_RB_FORCE_WAKEUP is specified in *flags*, notification of + * new data availability is sent unconditionally. + * Return + * Nothing. Always succeeds. + * + * void bpf_ringbuf_discard(void *data, u64 flags) + * Description + * Discard reserved ring buffer sample, pointed to by *data*. + * If BPF_RB_NO_WAKEUP is specified in *flags*, no notification of + * new data availability is sent. + * IF BPF_RB_FORCE_WAKEUP is specified in *flags*, notification of + * new data availability is sent unconditionally. + * Return + * Nothing. Always succeeds. + * + * u64 bpf_ringbuf_query(void *ringbuf, u64 flags) + * Description + * Query various characteristics of provided ring buffer. What + * exactly is queries is determined by *flags*: + * - BPF_RB_AVAIL_DATA - amount of data not yet consumed; + * - BPF_RB_RING_SIZE - the size of ring buffer; + * - BPF_RB_CONS_POS - consumer position (can wrap around); + * - BPF_RB_PROD_POS - producer(s) position (can wrap around); + * Data returned is just a momentary snapshots of actual values + * and could be inaccurate, so this facility should be used to + * power heuristics and for reporting, not to make 100% correct + * calculation. + * Return + * Requested value, or 0, if flags are not recognized. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3288,7 +3342,12 @@ union bpf_attr { FN(seq_printf), \ FN(seq_write), \ FN(sk_cgroup_id), \ - FN(sk_ancestor_cgroup_id), + FN(sk_ancestor_cgroup_id), \ + FN(ringbuf_output), \ + FN(ringbuf_reserve), \ + FN(ringbuf_submit), \ + FN(ringbuf_discard), \ + FN(ringbuf_query), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call @@ -3398,6 +3457,29 @@ enum { BPF_F_GET_BRANCH_RECORDS_SIZE = (1ULL << 0), }; +/* BPF_FUNC_bpf_ringbuf_commit, BPF_FUNC_bpf_ringbuf_discard, and + * BPF_FUNC_bpf_ringbuf_output flags. + */ +enum { + BPF_RB_NO_WAKEUP = (1ULL << 0), + BPF_RB_FORCE_WAKEUP = (1ULL << 1), +}; + +/* BPF_FUNC_bpf_ringbuf_query flags */ +enum { + BPF_RB_AVAIL_DATA = 0, + BPF_RB_RING_SIZE = 1, + BPF_RB_CONS_POS = 2, + BPF_RB_PROD_POS = 3, +}; + +/* BPF ring buffer constants */ +enum { + BPF_RINGBUF_BUSY_BIT = (1U << 31), + BPF_RINGBUF_DISCARD_BIT = (1U << 30), + BPF_RINGBUF_HDR_SZ = 8, +}; + /* Mode for BPF_FUNC_skb_adjust_room helper. */ enum bpf_adj_room_mode { BPF_ADJ_ROOM_NET, diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index 375b933010dd..8fca02f64811 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -4,7 +4,7 @@ CFLAGS_core.o += $(call cc-disable-warning, override-init) obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o bpf_iter.o map_iter.o task_iter.o obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o -obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o +obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o ringbuf.o obj-$(CONFIG_BPF_SYSCALL) += disasm.o obj-$(CONFIG_BPF_JIT) += trampoline.o obj-$(CONFIG_BPF_SYSCALL) += btf.o diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index bb4fb634275e..be43ab3e619f 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -635,6 +635,16 @@ bpf_base_func_proto(enum bpf_func_id func_id) return &bpf_ktime_get_ns_proto; case BPF_FUNC_ktime_get_boot_ns: return &bpf_ktime_get_boot_ns_proto; + case BPF_FUNC_ringbuf_output: + return &bpf_ringbuf_output_proto; + case BPF_FUNC_ringbuf_reserve: + return &bpf_ringbuf_reserve_proto; + case BPF_FUNC_ringbuf_submit: + return &bpf_ringbuf_submit_proto; + case BPF_FUNC_ringbuf_discard: + return &bpf_ringbuf_discard_proto; + case BPF_FUNC_ringbuf_query: + return &bpf_ringbuf_query_proto; default: break; } diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c new file mode 100644 index 000000000000..180414bb0d3e --- /dev/null +++ b/kernel/bpf/ringbuf.c @@ -0,0 +1,501 @@ +#include <linux/bpf.h> +#include <linux/btf.h> +#include <linux/err.h> +#include <linux/irq_work.h> +#include <linux/slab.h> +#include <linux/filter.h> +#include <linux/mm.h> +#include <linux/vmalloc.h> +#include <linux/wait.h> +#include <linux/poll.h> +#include <uapi/linux/btf.h> + +#define RINGBUF_CREATE_FLAG_MASK (BPF_F_NUMA_NODE) + +/* non-mmap()'able part of bpf_ringbuf (everything up to consumer page) */ +#define RINGBUF_PGOFF \ + (offsetof(struct bpf_ringbuf, consumer_pos) >> PAGE_SHIFT) +/* consumer page and producer page */ +#define RINGBUF_POS_PAGES 2 + +#define RINGBUF_MAX_RECORD_SZ (UINT_MAX/4) + +/* Maximum size of ring buffer area is limited by 32-bit page offset within + * record header, counted in pages. Reserve 8 bits for extensibility, and take + * into account few extra pages for consumer/producer pages and + * non-mmap()'able parts. This gives 64GB limit, which seems plenty for single + * ring buffer. + */ +#define RINGBUF_MAX_DATA_SZ \ + (((1ULL << 24) - RINGBUF_POS_PAGES - RINGBUF_PGOFF) * PAGE_SIZE) + +struct bpf_ringbuf { + wait_queue_head_t waitq; + struct irq_work work; + u64 mask; + struct page **pages; + int nr_pages; + spinlock_t spinlock ____cacheline_aligned_in_smp; + /* Consumer and producer counters are put into separate pages to allow + * mapping consumer page as r/w, but restrict producer page to r/o. + * This protects producer position from being modified by user-space + * application and ruining in-kernel position tracking. + */ + unsigned long consumer_pos __aligned(PAGE_SIZE); + unsigned long producer_pos __aligned(PAGE_SIZE); + char data[] __aligned(PAGE_SIZE); +}; + +struct bpf_ringbuf_map { + struct bpf_map map; + struct bpf_map_memory memory; + struct bpf_ringbuf *rb; +}; + +/* 8-byte ring buffer record header structure */ +struct bpf_ringbuf_hdr { + u32 len; + u32 pg_off; +}; + +static struct bpf_ringbuf *bpf_ringbuf_area_alloc(size_t data_sz, int numa_node) +{ + const gfp_t flags = GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN | + __GFP_ZERO; + int nr_meta_pages = RINGBUF_PGOFF + RINGBUF_POS_PAGES; + int nr_data_pages = data_sz >> PAGE_SHIFT; + int nr_pages = nr_meta_pages + nr_data_pages; + struct page **pages, *page; + struct bpf_ringbuf *rb; + size_t array_size; + int i; + + /* Each data page is mapped twice to allow "virtual" + * continuous read of samples wrapping around the end of ring + * buffer area: + * ------------------------------------------------------ + * | meta pages | real data pages | same data pages | + * ------------------------------------------------------ + * | | 1 2 3 4 5 6 7 8 9 | 1 2 3 4 5 6 7 8 9 | + * ------------------------------------------------------ + * | | TA DA | TA DA | + * ------------------------------------------------------ + * ^^^^^^^ + * | + * Here, no need to worry about special handling of wrapped-around + * data due to double-mapped data pages. This works both in kernel and + * when mmap()'ed in user-space, simplifying both kernel and + * user-space implementations significantly. + */ + array_size = (nr_meta_pages + 2 * nr_data_pages) * sizeof(*pages); + if (array_size > PAGE_SIZE) + pages = vmalloc_node(array_size, numa_node); + else + pages = kmalloc_node(array_size, flags, numa_node); + if (!pages) + return NULL; + + for (i = 0; i < nr_pages; i++) { + page = alloc_pages_node(numa_node, flags, 0); + if (!page) { + nr_pages = i; + goto err_free_pages; + } + pages[i] = page; + if (i >= nr_meta_pages) + pages[nr_data_pages + i] = page; + } + + rb = vmap(pages, nr_meta_pages + 2 * nr_data_pages, + VM_ALLOC | VM_USERMAP, PAGE_KERNEL); + if (rb) { + rb->pages = pages; + rb->nr_pages = nr_pages; + return rb; + } + +err_free_pages: + for (i = 0; i < nr_pages; i++) + __free_page(pages[i]); + kvfree(pages); + return NULL; +} + +static void bpf_ringbuf_notify(struct irq_work *work) +{ + struct bpf_ringbuf *rb = container_of(work, struct bpf_ringbuf, work); + + wake_up_all(&rb->waitq); +} + +static struct bpf_ringbuf *bpf_ringbuf_alloc(size_t data_sz, int numa_node) +{ + struct bpf_ringbuf *rb; + + if (!data_sz || !PAGE_ALIGNED(data_sz)) + return ERR_PTR(-EINVAL); + +#ifdef CONFIG_64BIT + /* on 32-bit arch, it's impossible to overflow record's hdr->pgoff */ + if (data_sz > RINGBUF_MAX_DATA_SZ) + return ERR_PTR(-E2BIG); +#endif + + rb = bpf_ringbuf_area_alloc(data_sz, numa_node); + if (!rb) + return ERR_PTR(-ENOMEM); + + spin_lock_init(&rb->spinlock); + init_waitqueue_head(&rb->waitq); + init_irq_work(&rb->work, bpf_ringbuf_notify); + + rb->mask = data_sz - 1; + rb->consumer_pos = 0; + rb->producer_pos = 0; + + return rb; +} + +static struct bpf_map *ringbuf_map_alloc(union bpf_attr *attr) +{ + struct bpf_ringbuf_map *rb_map; + u64 cost; + int err; + + if (attr->map_flags & ~RINGBUF_CREATE_FLAG_MASK) + return ERR_PTR(-EINVAL); + + if (attr->key_size || attr->value_size || + attr->max_entries == 0 || !PAGE_ALIGNED(attr->max_entries)) + return ERR_PTR(-EINVAL); + + rb_map = kzalloc(sizeof(*rb_map), GFP_USER); + if (!rb_map) + return ERR_PTR(-ENOMEM); + + bpf_map_init_from_attr(&rb_map->map, attr); + + cost = sizeof(struct bpf_ringbuf_map) + + sizeof(struct bpf_ringbuf) + + attr->max_entries; + err = bpf_map_charge_init(&rb_map->map.memory, cost); + if (err) + goto err_free_map; + + rb_map->rb = bpf_ringbuf_alloc(attr->max_entries, rb_map->map.numa_node); + if (IS_ERR(rb_map->rb)) { + err = PTR_ERR(rb_map->rb); + goto err_uncharge; + } + + return &rb_map->map; + +err_uncharge: + bpf_map_charge_finish(&rb_map->map.memory); +err_free_map: + kfree(rb_map); + return ERR_PTR(err); +} + +static void bpf_ringbuf_free(struct bpf_ringbuf *rb) +{ + /* copy pages pointer and nr_pages to local variable, as we are going + * to unmap rb itself with vunmap() below + */ + struct page **pages = rb->pages; + int i, nr_pages = rb->nr_pages; + + vunmap(rb); + for (i = 0; i < nr_pages; i++) + __free_page(pages[i]); + kvfree(pages); +} + +static void ringbuf_map_free(struct bpf_map *map) +{ + struct bpf_ringbuf_map *rb_map; + + /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, + * so the programs (can be more than one that used this map) were + * disconnected from events. Wait for outstanding critical sections in + * these programs to complete + */ + synchronize_rcu(); + + rb_map = container_of(map, struct bpf_ringbuf_map, map); + bpf_ringbuf_free(rb_map->rb); + kfree(rb_map); +} + +static void *ringbuf_map_lookup_elem(struct bpf_map *map, void *key) +{ + return ERR_PTR(-ENOTSUPP); +} + +static int ringbuf_map_update_elem(struct bpf_map *map, void *key, void *value, + u64 flags) +{ + return -ENOTSUPP; +} + +static int ringbuf_map_delete_elem(struct bpf_map *map, void *key) +{ + return -ENOTSUPP; +} + +static int ringbuf_map_get_next_key(struct bpf_map *map, void *key, + void *next_key) +{ + return -ENOTSUPP; +} + +static size_t bpf_ringbuf_mmap_page_cnt(const struct bpf_ringbuf *rb) +{ + size_t data_pages = (rb->mask + 1) >> PAGE_SHIFT; + + /* consumer page + producer page + 2 x data pages */ + return RINGBUF_POS_PAGES + 2 * data_pages; +} + +static int ringbuf_map_mmap(struct bpf_map *map, struct vm_area_struct *vma) +{ + struct bpf_ringbuf_map *rb_map; + size_t mmap_sz; + + rb_map = container_of(map, struct bpf_ringbuf_map, map); + mmap_sz = bpf_ringbuf_mmap_page_cnt(rb_map->rb) << PAGE_SHIFT; + + if (vma->vm_pgoff * PAGE_SIZE + (vma->vm_end - vma->vm_start) > mmap_sz) + return -EINVAL; + + return remap_vmalloc_range(vma, rb_map->rb, + vma->vm_pgoff + RINGBUF_PGOFF); +} + +static unsigned long ringbuf_avail_data_sz(struct bpf_ringbuf *rb) +{ + unsigned long cons_pos, prod_pos; + + cons_pos = smp_load_acquire(&rb->consumer_pos); + prod_pos = smp_load_acquire(&rb->producer_pos); + return prod_pos - cons_pos; +} + +static __poll_t ringbuf_map_poll(struct bpf_map *map, struct file *filp, + struct poll_table_struct *pts) +{ + struct bpf_ringbuf_map *rb_map; + + rb_map = container_of(map, struct bpf_ringbuf_map, map); + poll_wait(filp, &rb_map->rb->waitq, pts); + + if (ringbuf_avail_data_sz(rb_map->rb)) + return EPOLLIN | EPOLLRDNORM; + return 0; +} + +const struct bpf_map_ops ringbuf_map_ops = { + .map_alloc = ringbuf_map_alloc, + .map_free = ringbuf_map_free, + .map_mmap = ringbuf_map_mmap, + .map_poll = ringbuf_map_poll, + .map_lookup_elem = ringbuf_map_lookup_elem, + .map_update_elem = ringbuf_map_update_elem, + .map_delete_elem = ringbuf_map_delete_elem, + .map_get_next_key = ringbuf_map_get_next_key, +}; + +/* Given pointer to ring buffer record metadata and struct bpf_ringbuf itself, + * calculate offset from record metadata to ring buffer in pages, rounded + * down. This page offset is stored as part of record metadata and allows to + * restore struct bpf_ringbuf * from record pointer. This page offset is + * stored at offset 4 of record metadata header. + */ +static size_t bpf_ringbuf_rec_pg_off(struct bpf_ringbuf *rb, + struct bpf_ringbuf_hdr *hdr) +{ + return ((void *)hdr - (void *)rb) >> PAGE_SHIFT; +} + +/* Given pointer to ring buffer record header, restore pointer to struct + * bpf_ringbuf itself by using page offset stored at offset 4 + */ +static struct bpf_ringbuf * +bpf_ringbuf_restore_from_rec(struct bpf_ringbuf_hdr *hdr) +{ + unsigned long addr = (unsigned long)(void *)hdr; + unsigned long off = (unsigned long)hdr->pg_off << PAGE_SHIFT; + + return (void*)((addr & PAGE_MASK) - off); +} + +static void *__bpf_ringbuf_reserve(struct bpf_ringbuf *rb, u64 size) +{ + unsigned long cons_pos, prod_pos, new_prod_pos, flags; + u32 len, pg_off; + struct bpf_ringbuf_hdr *hdr; + + if (unlikely(size > RINGBUF_MAX_RECORD_SZ)) + return NULL; + + len = round_up(size + BPF_RINGBUF_HDR_SZ, 8); + cons_pos = smp_load_acquire(&rb->consumer_pos); + + if (in_nmi()) { + if (!spin_trylock_irqsave(&rb->spinlock, flags)) + return NULL; + } else { + spin_lock_irqsave(&rb->spinlock, flags); + } + + prod_pos = rb->producer_pos; + new_prod_pos = prod_pos + len; + + /* check for out of ringbuf space by ensuring producer position + * doesn't advance more than (ringbuf_size - 1) ahead + */ + if (new_prod_pos - cons_pos > rb->mask) { + spin_unlock_irqrestore(&rb->spinlock, flags); + return NULL; + } + + hdr = (void *)rb->data + (prod_pos & rb->mask); + pg_off = bpf_ringbuf_rec_pg_off(rb, hdr); + hdr->len = size | BPF_RINGBUF_BUSY_BIT; + hdr->pg_off = pg_off; + + /* pairs with consumer's smp_load_acquire() */ + smp_store_release(&rb->producer_pos, new_prod_pos); + + spin_unlock_irqrestore(&rb->spinlock, flags); + + return (void *)hdr + BPF_RINGBUF_HDR_SZ; +} + +BPF_CALL_3(bpf_ringbuf_reserve, struct bpf_map *, map, u64, size, u64, flags) +{ + struct bpf_ringbuf_map *rb_map; + + if (unlikely(flags)) + return 0; + + rb_map = container_of(map, struct bpf_ringbuf_map, map); + return (unsigned long)__bpf_ringbuf_reserve(rb_map->rb, size); +} + +const struct bpf_func_proto bpf_ringbuf_reserve_proto = { + .func = bpf_ringbuf_reserve, + .ret_type = RET_PTR_TO_ALLOC_MEM_OR_NULL, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_CONST_ALLOC_SIZE_OR_ZERO, + .arg3_type = ARG_ANYTHING, +}; + +static void bpf_ringbuf_commit(void *sample, u64 flags, bool discard) +{ + unsigned long rec_pos, cons_pos; + struct bpf_ringbuf_hdr *hdr; + struct bpf_ringbuf *rb; + u32 new_len; + + hdr = sample - BPF_RINGBUF_HDR_SZ; + rb = bpf_ringbuf_restore_from_rec(hdr); + new_len = hdr->len ^ BPF_RINGBUF_BUSY_BIT; + if (discard) + new_len |= BPF_RINGBUF_DISCARD_BIT; + + /* update record header with correct final size prefix */ + xchg(&hdr->len, new_len); + + /* if consumer caught up and is waiting for our record, notify about + * new data availability + */ + rec_pos = (void *)hdr - (void *)rb->data; + cons_pos = smp_load_acquire(&rb->consumer_pos) & rb->mask; + + if (flags & BPF_RB_FORCE_WAKEUP) + irq_work_queue(&rb->work); + else if (cons_pos == rec_pos && !(flags & BPF_RB_NO_WAKEUP)) + irq_work_queue(&rb->work); +} + +BPF_CALL_2(bpf_ringbuf_submit, void *, sample, u64, flags) +{ + bpf_ringbuf_commit(sample, flags, false /* discard */); + return 0; +} + +const struct bpf_func_proto bpf_ringbuf_submit_proto = { + .func = bpf_ringbuf_submit, + .ret_type = RET_VOID, + .arg1_type = ARG_PTR_TO_ALLOC_MEM, + .arg2_type = ARG_ANYTHING, +}; + +BPF_CALL_2(bpf_ringbuf_discard, void *, sample, u64, flags) +{ + bpf_ringbuf_commit(sample, flags, true /* discard */); + return 0; +} + +const struct bpf_func_proto bpf_ringbuf_discard_proto = { + .func = bpf_ringbuf_discard, + .ret_type = RET_VOID, + .arg1_type = ARG_PTR_TO_ALLOC_MEM, + .arg2_type = ARG_ANYTHING, +}; + +BPF_CALL_4(bpf_ringbuf_output, struct bpf_map *, map, void *, data, u64, size, + u64, flags) +{ + struct bpf_ringbuf_map *rb_map; + void *rec; + + if (unlikely(flags & ~(BPF_RB_NO_WAKEUP | BPF_RB_FORCE_WAKEUP))) + return -EINVAL; + + rb_map = container_of(map, struct bpf_ringbuf_map, map); + rec = __bpf_ringbuf_reserve(rb_map->rb, size); + if (!rec) + return -EAGAIN; + + memcpy(rec, data, size); + bpf_ringbuf_commit(rec, flags, false /* discard */); + return 0; +} + +const struct bpf_func_proto bpf_ringbuf_output_proto = { + .func = bpf_ringbuf_output, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_MEM, + .arg3_type = ARG_CONST_SIZE_OR_ZERO, + .arg4_type = ARG_ANYTHING, +}; + +BPF_CALL_2(bpf_ringbuf_query, struct bpf_map *, map, u64, flags) +{ + struct bpf_ringbuf *rb; + + rb = container_of(map, struct bpf_ringbuf_map, map)->rb; + + switch (flags) { + case BPF_RB_AVAIL_DATA: + return ringbuf_avail_data_sz(rb); + case BPF_RB_RING_SIZE: + return rb->mask + 1; + case BPF_RB_CONS_POS: + return smp_load_acquire(&rb->consumer_pos); + case BPF_RB_PROD_POS: + return smp_load_acquire(&rb->producer_pos); + default: + return 0; + } +} + +const struct bpf_func_proto bpf_ringbuf_query_proto = { + .func = bpf_ringbuf_query, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_ANYTHING, +}; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 2c969a9b90d3..9de3540fa90c 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -26,6 +26,7 @@ #include <linux/audit.h> #include <uapi/linux/btf.h> #include <linux/bpf_lsm.h> +#include <linux/poll.h> #define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \ (map)->map_type == BPF_MAP_TYPE_CGROUP_ARRAY || \ @@ -662,6 +663,16 @@ out: return err; } +static __poll_t bpf_map_poll(struct file *filp, struct poll_table_struct *pts) +{ + struct bpf_map *map = filp->private_data; + + if (map->ops->map_poll) + return map->ops->map_poll(map, filp, pts); + + return EPOLLERR; +} + const struct file_operations bpf_map_fops = { #ifdef CONFIG_PROC_FS .show_fdinfo = bpf_map_show_fdinfo, @@ -670,6 +681,7 @@ const struct file_operations bpf_map_fops = { .read = bpf_dummy_read, .write = bpf_dummy_write, .mmap = bpf_map_mmap, + .poll = bpf_map_poll, }; int bpf_map_new_fd(struct bpf_map *map, int flags) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 6d725a26f66e..5c7bbaac81ef 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -233,6 +233,7 @@ struct bpf_call_arg_meta { bool pkt_access; int regno; int access_size; + int mem_size; u64 msize_max_value; int ref_obj_id; int func_id; @@ -408,7 +409,8 @@ static bool reg_type_may_be_null(enum bpf_reg_type type) type == PTR_TO_SOCKET_OR_NULL || type == PTR_TO_SOCK_COMMON_OR_NULL || type == PTR_TO_TCP_SOCK_OR_NULL || - type == PTR_TO_BTF_ID_OR_NULL; + type == PTR_TO_BTF_ID_OR_NULL || + type == PTR_TO_MEM_OR_NULL; } static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg) @@ -422,7 +424,9 @@ static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type) return type == PTR_TO_SOCKET || type == PTR_TO_SOCKET_OR_NULL || type == PTR_TO_TCP_SOCK || - type == PTR_TO_TCP_SOCK_OR_NULL; + type == PTR_TO_TCP_SOCK_OR_NULL || + type == PTR_TO_MEM || + type == PTR_TO_MEM_OR_NULL; } static bool arg_type_may_be_refcounted(enum bpf_arg_type type) @@ -436,7 +440,9 @@ static bool arg_type_may_be_refcounted(enum bpf_arg_type type) */ static bool is_release_function(enum bpf_func_id func_id) { - return func_id == BPF_FUNC_sk_release; + return func_id == BPF_FUNC_sk_release || + func_id == BPF_FUNC_ringbuf_submit || + func_id == BPF_FUNC_ringbuf_discard; } static bool may_be_acquire_function(enum bpf_func_id func_id) @@ -444,7 +450,8 @@ static bool may_be_acquire_function(enum bpf_func_id func_id) return func_id == BPF_FUNC_sk_lookup_tcp || func_id == BPF_FUNC_sk_lookup_udp || func_id == BPF_FUNC_skc_lookup_tcp || - func_id == BPF_FUNC_map_lookup_elem; + func_id == BPF_FUNC_map_lookup_elem || + func_id == BPF_FUNC_ringbuf_reserve; } static bool is_acquire_function(enum bpf_func_id func_id, @@ -454,7 +461,8 @@ static bool is_acquire_function(enum bpf_func_id func_id, if (func_id == BPF_FUNC_sk_lookup_tcp || func_id == BPF_FUNC_sk_lookup_udp || - func_id == BPF_FUNC_skc_lookup_tcp) + func_id == BPF_FUNC_skc_lookup_tcp || + func_id == BPF_FUNC_ringbuf_reserve) return true; if (func_id == BPF_FUNC_map_lookup_elem && @@ -494,6 +502,8 @@ static const char * const reg_type_str[] = { [PTR_TO_XDP_SOCK] = "xdp_sock", [PTR_TO_BTF_ID] = "ptr_", [PTR_TO_BTF_ID_OR_NULL] = "ptr_or_null_", + [PTR_TO_MEM] = "mem", + [PTR_TO_MEM_OR_NULL] = "mem_or_null", }; static char slot_type_char[] = { @@ -2468,32 +2478,49 @@ static int check_map_access_type(struct bpf_verifier_env *env, u32 regno, return 0; } -/* check read/write into map element returned by bpf_map_lookup_elem() */ -static int __check_map_access(struct bpf_verifier_env *env, u32 regno, int off, - int size, bool zero_size_allowed) +/* check read/write into memory region (e.g., map value, ringbuf sample, etc) */ +static int __check_mem_access(struct bpf_verifier_env *env, int regno, + int off, int size, u32 mem_size, + bool zero_size_allowed) { - struct bpf_reg_state *regs = cur_regs(env); - struct bpf_map *map = regs[regno].map_ptr; + bool size_ok = size > 0 || (size == 0 && zero_size_allowed); + struct bpf_reg_state *reg; + + if (off >= 0 && size_ok && (u64)off + size <= mem_size) + return 0; - if (off < 0 || size < 0 || (size == 0 && !zero_size_allowed) || - off + size > map->value_size) { + reg = &cur_regs(env)[regno]; + switch (reg->type) { + case PTR_TO_MAP_VALUE: verbose(env, "invalid access to map value, value_size=%d off=%d size=%d\n", - map->value_size, off, size); - return -EACCES; + mem_size, off, size); + break; + case PTR_TO_PACKET: + case PTR_TO_PACKET_META: + case PTR_TO_PACKET_END: + verbose(env, "invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n", + off, size, regno, reg->id, off, mem_size); + break; + case PTR_TO_MEM: + default: + verbose(env, "invalid access to memory, mem_size=%u off=%d size=%d\n", + mem_size, off, size); } - return 0; + + return -EACCES; } -/* check read/write into a map element with possible variable offset */ -static int check_map_access(struct bpf_verifier_env *env, u32 regno, - int off, int size, bool zero_size_allowed) +/* check read/write into a memory region with possible variable offset */ +static int check_mem_region_access(struct bpf_verifier_env *env, u32 regno, + int off, int size, u32 mem_size, + bool zero_size_allowed) { struct bpf_verifier_state *vstate = env->cur_state; struct bpf_func_state *state = vstate->frame[vstate->curframe]; struct bpf_reg_state *reg = &state->regs[regno]; int err; - /* We may have adjusted the register to this map value, so we + /* We may have adjusted the register pointing to memory region, so we * need to try adding each of min_value and max_value to off * to make sure our theoretical access will be safe. */ @@ -2514,10 +2541,10 @@ static int check_map_access(struct bpf_verifier_env *env, u32 regno, regno); return -EACCES; } - err = __check_map_access(env, regno, reg->smin_value + off, size, - zero_size_allowed); + err = __check_mem_access(env, regno, reg->smin_value + off, size, + mem_size, zero_size_allowed); if (err) { - verbose(env, "R%d min value is outside of the array range\n", + verbose(env, "R%d min value is outside of the allowed memory range\n", regno); return err; } @@ -2527,18 +2554,38 @@ static int check_map_access(struct bpf_verifier_env *env, u32 regno, * If reg->umax_value + off could overflow, treat that as unbounded too. */ if (reg->umax_value >= BPF_MAX_VAR_OFF) { - verbose(env, "R%d unbounded memory access, make s |