On 2021/7/20 3:02 AM, Andrii Nakryiko wrote: > On Mon, Jul 19, 2021 at 8:18 AM Hengqi Chen <hengqi.chen@xxxxxxxxx> wrote: >> >> Add vfs_* and security_* to bpf_d_path allowlist, so that we can use >> bpf_d_path helper to extract full file path from these functions' >> `struct path *` and `struct file *` arguments. This will help tools >> like IOVisor's filetop[2]/filelife to get full file path. >> >> Changes since v1: [1] >> - Alexei and Yonghong suggested that bpf_d_path helper could also >> apply to vfs_* and security_file_* kernel functions. Added them. >> >> [1] https://lore.kernel.org/bpf/20210712162424.2034006-1-hengqi.chen@xxxxxxxxx/ >> [2] https://github.com/iovisor/bcc/issues/3527 >> >> Signed-off-by: Hengqi Chen <hengqi.chen@xxxxxxxxx> >> --- >> kernel/trace/bpf_trace.c | 50 ++++++++++++++++++++++++++++++++++++++-- >> 1 file changed, 48 insertions(+), 2 deletions(-) >> >> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c >> index 08906007306d..c784f3c7143f 100644 >> --- a/kernel/trace/bpf_trace.c >> +++ b/kernel/trace/bpf_trace.c >> @@ -850,16 +850,62 @@ BPF_CALL_3(bpf_d_path, struct path *, path, char *, buf, u32, sz) >> BTF_SET_START(btf_allowlist_d_path) >> #ifdef CONFIG_SECURITY >> BTF_ID(func, security_file_permission) >> -BTF_ID(func, security_inode_getattr) >> BTF_ID(func, security_file_open) >> +BTF_ID(func, security_file_ioctl) >> +BTF_ID(func, security_file_free) >> +BTF_ID(func, security_file_alloc) >> +BTF_ID(func, security_file_lock) >> +BTF_ID(func, security_file_fcntl) >> +BTF_ID(func, security_file_set_fowner) >> +BTF_ID(func, security_file_receive) >> +BTF_ID(func, security_inode_getattr) >> #endif >> #ifdef CONFIG_SECURITY_PATH >> BTF_ID(func, security_path_truncate) >> +BTF_ID(func, security_path_notify) >> +BTF_ID(func, security_path_unlink) >> +BTF_ID(func, security_path_mkdir) >> +BTF_ID(func, security_path_rmdir) >> +BTF_ID(func, security_path_mknod) >> +BTF_ID(func, security_path_symlink) >> +BTF_ID(func, security_path_link) >> +BTF_ID(func, security_path_rename) >> +BTF_ID(func, security_path_chmod) >> +BTF_ID(func, security_path_chown) >> +BTF_ID(func, security_path_chroot) >> #endif >> BTF_ID(func, vfs_truncate) >> BTF_ID(func, vfs_fallocate) >> -BTF_ID(func, dentry_open) >> BTF_ID(func, vfs_getattr) >> +BTF_ID(func, vfs_fadvise) >> +BTF_ID(func, vfs_fchmod) >> +BTF_ID(func, vfs_fchown) >> +BTF_ID(func, vfs_open) >> +BTF_ID(func, vfs_setpos) >> +BTF_ID(func, vfs_llseek) >> +BTF_ID(func, vfs_read) >> +BTF_ID(func, vfs_write) >> +BTF_ID(func, vfs_iocb_iter_read) >> +BTF_ID(func, vfs_iter_read) >> +BTF_ID(func, vfs_readv) >> +BTF_ID(func, vfs_iocb_iter_write) >> +BTF_ID(func, vfs_iter_write) >> +BTF_ID(func, vfs_writev) >> +BTF_ID(func, vfs_copy_file_range) >> +BTF_ID(func, vfs_getattr_nosec) >> +BTF_ID(func, vfs_ioctl) >> +BTF_ID(func, vfs_fsync_range) >> +BTF_ID(func, vfs_fsync) >> +BTF_ID(func, vfs_utimes) >> +BTF_ID(func, vfs_statfs) >> +BTF_ID(func, vfs_dedupe_file_range_one) >> +BTF_ID(func, vfs_dedupe_file_range) >> +BTF_ID(func, vfs_clone_file_range) >> +BTF_ID(func, vfs_cancel_lock) >> +BTF_ID(func, vfs_test_lock) >> +BTF_ID(func, vfs_setlease) >> +BTF_ID(func, vfs_lock_file) >> +BTF_ID(func, dentry_open) >> BTF_ID(func, filp_close) >> BTF_SET_END(btf_allowlist_d_path) >> > > Before we lend this expanded list of allowed functions, I think we > should address an issue that comes up from time to time with .BTF_ids. > Sometimes the referenced function can be changed from global to static > and get inlined by the compiler, and thus disappears from BTF > altogether. This will result in kernel build failure causing a lot of > confusion, because the change might be done by people unfamiliar with > the BTF_ID() stuff and not even aware of it. > Thanks for the detailed background. I was able to reproduce this kernel build failure. > This came up a few times before and it's frustrating for everyone > involved. Before we proceed with extending the list further, let's > teach resolve_btfids to warn on such missing function (so that we are > at least aware) but otherwise ignore it (probably leaving ID as zero, > but let's also confirm that all the users of BTF_ID() stuff handle > those zeros correctly). > Do you mean that resolve_btfids should be updated to emit warning messages instead of aborting the build process ? >> -- >> 2.25.1 >>
