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, invalid attach type, and invalid prog type. Links: [1] https://lore.kernel.org/bpf/[email protected]/ Signed-off-by: Leon Hwang <[email protected]> --- include/linux/bpf_verifier.h | 1 + kernel/bpf/log.c | 19 +++++++++++------- kernel/bpf/syscall.c | 39 ++++++++++++++++++++++++++++++------ 3 files changed, 46 insertions(+), 13 deletions(-) diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 951a90458d18..de9845526ce0 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -896,6 +896,7 @@ struct bpf_verifier_log *bpf_log_attr_create_vlog(struct bpf_log_attr *attr_log, struct bpf_common_attr *common, bpfptr_t uattr, u32 size); int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log); +int bpf_log_attr_report_size(struct bpf_log_attr *attr, u32 size); #define BPF_MAX_SUBPROGS 256 diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c index 5432c0fc442b..2bcd62d9ad88 100644 --- a/kernel/bpf/log.c +++ b/kernel/bpf/log.c @@ -884,17 +884,22 @@ struct bpf_verifier_log *bpf_log_attr_create_vlog(struct bpf_log_attr *attr_log, return log; } +int bpf_log_attr_report_size(struct bpf_log_attr *attr, u32 size) +{ + if (attr->offsetof_true_size && + copy_to_bpfptr_offset(attr->uattr, attr->offsetof_true_size, &size, sizeof(size))) + return -EFAULT; + + return 0; +} + int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log) { u32 log_true_size; - int err; + int err, ret; err = bpf_vlog_finalize(log, &log_true_size); - if (attr->offsetof_true_size && - copy_to_bpfptr_offset(attr->uattr, attr->offsetof_true_size, &log_true_size, - sizeof(log_true_size))) - return -EFAULT; - - return err; + ret = bpf_log_attr_report_size(attr, log_true_size); + return ret ? ret : err; } diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 849bc9136299..201658b75ab7 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -5856,8 +5856,11 @@ 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; @@ -5867,14 +5870,28 @@ 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; + } + + ret = bpf_log_attr_report_size(&attr_log, 0); + if (ret) + goto put_prog; switch (prog->type) { case BPF_PROG_TYPE_CGROUP_SKB: @@ -5953,12 +5970,22 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr) ret = bpf_uprobe_multi_link_attach(attr, prog); break; default: + bpf_log(log, "Invalid prog type.\n"); ret = -EINVAL; } out: - if (ret < 0) + if (ret < 0) { + int err = bpf_log_attr_finalize(&attr_log, log); + + ret = err ? err : ret; + } + +put_prog: + if (ret < 0 && prog) bpf_prog_put(prog); + + kfree(log); return ret; } @@ -6530,7 +6557,7 @@ 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
