From b1d18a7574d0df5eb4117c14742baf8bc2b9bb74 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Wed, 9 Feb 2022 15:19:57 -0800 Subject: [PATCH] bpf: Extend sys_bpf commands for bpf_syscall programs. bpf_sycall programs can be used directly by the kernel modules to load programs and create maps via kernel skeleton. . Export bpf_sys_bpf syscall wrapper to be used in kernel skeleton. . Export bpf_map_get to be used in kernel skeleton. . Allow prog_run cmd for bpf_syscall programs with recursion check. . Enable link_create and raw_tp_open cmds. Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220209232001.27490-2-alexei.starovoitov@gmail.com --- kernel/bpf/syscall.c | 38 ++++++++++++++++++++++++++++++++++---- 1 file changed, 34 insertions(+), 4 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 72ce1edde950..49f88b30662a 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -985,6 +985,7 @@ struct bpf_map *bpf_map_get(u32 ufd) return map; } +EXPORT_SYMBOL(bpf_map_get); struct bpf_map *bpf_map_get_with_uref(u32 ufd) { @@ -4756,23 +4757,52 @@ static bool syscall_prog_is_valid_access(int off, int size, return true; } -BPF_CALL_3(bpf_sys_bpf, int, cmd, void *, attr, u32, attr_size) +BPF_CALL_3(bpf_sys_bpf, int, cmd, union bpf_attr *, attr, u32, attr_size) { + struct bpf_prog * __maybe_unused prog; + switch (cmd) { case BPF_MAP_CREATE: case BPF_MAP_UPDATE_ELEM: case BPF_MAP_FREEZE: case BPF_PROG_LOAD: case BPF_BTF_LOAD: + case BPF_LINK_CREATE: + case BPF_RAW_TRACEPOINT_OPEN: break; - /* case BPF_PROG_TEST_RUN: - * is not part of this list to prevent recursive test_run - */ +#ifdef CONFIG_BPF_JIT /* __bpf_prog_enter_sleepable used by trampoline and JIT */ + case BPF_PROG_TEST_RUN: + if (attr->test.data_in || attr->test.data_out || + attr->test.ctx_out || attr->test.duration || + attr->test.repeat || attr->test.flags) + return -EINVAL; + + prog = bpf_prog_get_type(attr->test.prog_fd, BPF_PROG_TYPE_SYSCALL); + if (IS_ERR(prog)) + return PTR_ERR(prog); + + if (attr->test.ctx_size_in < prog->aux->max_ctx_offset || + attr->test.ctx_size_in > U16_MAX) { + bpf_prog_put(prog); + return -EINVAL; + } + + if (!__bpf_prog_enter_sleepable(prog)) { + /* recursion detected */ + bpf_prog_put(prog); + return -EBUSY; + } + attr->test.retval = bpf_prog_run(prog, (void *) (long) attr->test.ctx_in); + __bpf_prog_exit_sleepable(prog, 0 /* bpf_prog_run does runtime stats */); + bpf_prog_put(prog); + return 0; +#endif default: return -EINVAL; } return __sys_bpf(cmd, KERNEL_BPFPTR(attr), attr_size); } +EXPORT_SYMBOL(bpf_sys_bpf); static const struct bpf_func_proto bpf_sys_bpf_proto = { .func = bpf_sys_bpf,