diff options
| -rw-r--r-- | include/linux/filter.h | 2 | ||||
| -rw-r--r-- | include/uapi/linux/bpf.h | 28 | ||||
| -rw-r--r-- | kernel/bpf/syscall.c | 163 |
3 files changed, 174 insertions, 19 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h index 1e2dddf21f3b..1fa26dc562ce 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -69,8 +69,6 @@ struct bpf_prog_aux; /* BPF program can access up to 512 bytes of stack space. */ #define MAX_BPF_STACK 512 -#define BPF_TAG_SIZE 8 - /* Helper macros for filter block array initializers. */ /* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */ diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index dd23f47ff00c..9b2c10b45733 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -86,6 +86,7 @@ enum bpf_cmd { BPF_MAP_GET_NEXT_ID, BPF_PROG_GET_FD_BY_ID, BPF_MAP_GET_FD_BY_ID, + BPF_OBJ_GET_INFO_BY_FD, }; enum bpf_map_type { @@ -222,6 +223,12 @@ union bpf_attr { }; __u32 next_id; }; + + struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */ + __u32 bpf_fd; + __u32 info_len; + __aligned_u64 info; + } info; } __attribute__((aligned(8))); /* BPF helper function descriptions: @@ -686,4 +693,25 @@ struct xdp_md { __u32 data_end; }; +#define BPF_TAG_SIZE 8 + +struct bpf_prog_info { + __u32 type; + __u32 id; + __u8 tag[BPF_TAG_SIZE]; + __u32 jited_prog_len; + __u32 xlated_prog_len; + __aligned_u64 jited_prog_insns; + __aligned_u64 xlated_prog_insns; +} __attribute__((aligned(8))); + +struct bpf_map_info { + __u32 type; + __u32 id; + __u32 key_size; + __u32 value_size; + __u32 max_entries; + __u32 map_flags; +} __attribute__((aligned(8))); + #endif /* _UAPI__LINUX_BPF_H__ */ diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 1802bb9c47d9..8942c820d620 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1239,6 +1239,145 @@ static int bpf_map_get_fd_by_id(const union bpf_attr *attr) return fd; } +static int check_uarg_tail_zero(void __user *uaddr, + size_t expected_size, + size_t actual_size) +{ + unsigned char __user *addr; + unsigned char __user *end; + unsigned char val; + int err; + + if (actual_size <= expected_size) + return 0; + + addr = uaddr + expected_size; + end = uaddr + actual_size; + + for (; addr < end; addr++) { + err = get_user(val, addr); + if (err) + return err; + if (val) + return -E2BIG; + } + + return 0; +} + +static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + struct bpf_prog_info __user *uinfo = u64_to_user_ptr(attr->info.info); + struct bpf_prog_info info = {}; + u32 info_len = attr->info.info_len; + char __user *uinsns; + u32 ulen; + int err; + + err = check_uarg_tail_zero(uinfo, sizeof(info), info_len); + if (err) + return err; + info_len = min_t(u32, sizeof(info), info_len); + + if (copy_from_user(&info, uinfo, info_len)) + return err; + + info.type = prog->type; + info.id = prog->aux->id; + + memcpy(info.tag, prog->tag, sizeof(prog->tag)); + + if (!capable(CAP_SYS_ADMIN)) { + info.jited_prog_len = 0; + info.xlated_prog_len = 0; + goto done; + } + + ulen = info.jited_prog_len; + info.jited_prog_len = prog->jited_len; + if (info.jited_prog_len && ulen) { + uinsns = u64_to_user_ptr(info.jited_prog_insns); + ulen = min_t(u32, info.jited_prog_len, ulen); + if (copy_to_user(uinsns, prog->bpf_func, ulen)) + return -EFAULT; + } + + ulen = info.xlated_prog_len; + info.xlated_prog_len = bpf_prog_size(prog->len); + if (info.xlated_prog_len && ulen) { + uinsns = u64_to_user_ptr(info.xlated_prog_insns); + ulen = min_t(u32, info.xlated_prog_len, ulen); + if (copy_to_user(uinsns, prog->insnsi, ulen)) + return -EFAULT; + } + +done: + if (copy_to_user(uinfo, &info, info_len) || + put_user(info_len, &uattr->info.info_len)) + return -EFAULT; + + return 0; +} + +static int bpf_map_get_info_by_fd(struct bpf_map *map, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + struct bpf_map_info __user *uinfo = u64_to_user_ptr(attr->info.info); + struct bpf_map_info info = {}; + u32 info_len = attr->info.info_len; + int err; + + err = check_uarg_tail_zero(uinfo, sizeof(info), info_len); + if (err) + return err; + info_len = min_t(u32, sizeof(info), info_len); + + info.type = map->map_type; + info.id = map->id; + info.key_size = map->key_size; + info.value_size = map->value_size; + info.max_entries = map->max_entries; + info.map_flags = map->map_flags; + + if (copy_to_user(uinfo, &info, info_len) || + put_user(info_len, &uattr->info.info_len)) + return -EFAULT; + + return 0; +} + +#define BPF_OBJ_GET_INFO_BY_FD_LAST_FIELD info.info + +static int bpf_obj_get_info_by_fd(const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + int ufd = attr->info.bpf_fd; + struct fd f; + int err; + + if (CHECK_ATTR(BPF_OBJ_GET_INFO_BY_FD)) + return -EINVAL; + + f = fdget(ufd); + if (!f.file) + return -EBADFD; + + if (f.file->f_op == &bpf_prog_fops) + err = bpf_prog_get_info_by_fd(f.file->private_data, attr, + uattr); + else if (f.file->f_op == &bpf_map_fops) + err = bpf_map_get_info_by_fd(f.file->private_data, attr, + uattr); + else + err = -EINVAL; + + fdput(f); + return err; +} + SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size) { union bpf_attr attr = {}; @@ -1258,23 +1397,10 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz * user-space does not rely on any kernel feature * extensions we dont know about yet. */ - if (size > sizeof(attr)) { - unsigned char __user *addr; - unsigned char __user *end; - unsigned char val; - - addr = (void __user *)uattr + sizeof(attr); - end = (void __user *)uattr + size; - - for (; addr < end; addr++) { - err = get_user(val, addr); - if (err) - return err; - if (val) - return -E2BIG; - } - size = sizeof(attr); - } + err = check_uarg_tail_zero(uattr, sizeof(attr), size); + if (err) + return err; + size = min_t(u32, size, sizeof(attr)); /* copy attributes from user space, may be less than sizeof(bpf_attr) */ if (copy_from_user(&attr, uattr, size) != 0) @@ -1330,6 +1456,9 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz case BPF_MAP_GET_FD_BY_ID: err = bpf_map_get_fd_by_id(&attr); break; + case BPF_OBJ_GET_INFO_BY_FD: + err = bpf_obj_get_info_by_fd(&attr, uattr); + break; default: err = -EINVAL; break; |