Similar to the syscall common attrs support for map_create [1], add the syscall common attrs support for link_create.
Create and finalize the internal verifier log instance. Then, report the error messages for invalid prog fd and invalid attach type. Links: [1] https://lore.kernel.org/bpf/[email protected]/ Signed-off-by: Leon Hwang <[email protected]> --- kernel/bpf/syscall.c | 34 +++++++++++++++++++++++++++------- 1 file changed, 27 insertions(+), 7 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 0f27604a54aa..252b479937a4 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -5839,10 +5839,13 @@ static int bpf_map_do_batch(const union bpf_attr *attr, } #define BPF_LINK_CREATE_LAST_FIELD link_create.uprobe_multi.path_fd -static int link_create(union bpf_attr *attr, bpfptr_t uattr) +static int link_create(union bpf_attr *attr, bpfptr_t uattr, struct bpf_common_attr *attr_common, + bpfptr_t uattr_common, u32 size_common) { + struct bpf_verifier_log *log; + struct bpf_log_attr attr_log; struct bpf_prog *prog; - int ret; + int ret, err; if (CHECK_ATTR(BPF_LINK_CREATE)) return -EINVAL; @@ -5850,14 +5853,24 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr) if (attr->link_create.attach_type == BPF_STRUCT_OPS) return bpf_struct_ops_link_create(attr); + log = bpf_log_attr_create_vlog(&attr_log, attr_common, uattr_common, size_common); + if (IS_ERR(log)) + return PTR_ERR(log); + prog = bpf_prog_get(attr->link_create.prog_fd); - if (IS_ERR(prog)) - return PTR_ERR(prog); + if (IS_ERR(prog)) { + bpf_log(log, "Invalid prog_fd.\n"); + ret = PTR_ERR(prog); + prog = NULL; + goto out; + } ret = bpf_prog_attach_check_attach_type(prog, attr->link_create.attach_type); - if (ret) + if (ret) { + bpf_log(log, "Invalid attach_type.\n"); goto out; + } switch (prog->type) { case BPF_PROG_TYPE_CGROUP_SKB: @@ -5940,7 +5953,14 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr) } out: - if (ret < 0) + /* preserve original error even if log finalization is successful */ + err = bpf_log_attr_finalize(&attr_log, log); + if (err) + ret = err; + + kfree(log); + + if (ret < 0 && prog) bpf_prog_put(prog); return ret; } @@ -6513,7 +6533,7 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size, err = bpf_map_do_batch(&attr, uattr.user, BPF_MAP_DELETE_BATCH); break; case BPF_LINK_CREATE: - err = link_create(&attr, uattr); + err = link_create(&attr, uattr, &attr_common, uattr_common, size_common); break; case BPF_LINK_UPDATE: err = link_update(&attr); -- 2.55.0
