Merge branch 'add-bpf_get_dentry_xattr'

Song Liu says:

====================
Add bpf_get_dentry_xattr

Add a kfunc to read xattr from dentry. Also add selftest for the new
kfunc.

Changes v3 => v4:
1. Fix selftest build.

V3: https://lore.kernel.org/bpf/20240806203340.3503805-1-song@kernel.org/T/#u

Changes v2 => v3:
1. Move the kfuncs to fs/bpf_fs_kfuncs.c.
2. Fix selftests build error on s390. (Alexei)

v2: https://lore.kernel.org/bpf/20240730230805.42205-1-song@kernel.org/T/#u

Changes v1 => v2:
1. Remove 3 kfuncs that are ready yet.

v1: https://lore.kernel.org/linux-fsdevel/20240725234706.655613-1-song@kernel.org/T/#u
====================

Link: https://lore.kernel.org/r/20240806230904.71194-1-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 0 insertions, 68 deletions

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index cd098846e251..d557bb11e0ff 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -24,7 +24,6 @@
 #include <linux/key.h>
 #include <linux/verification.h>
 #include <linux/namei.h>
-#include <linux/fileattr.h>
 
 #include <net/bpf_sk_storage.h>
 
@@ -1439,73 +1438,6 @@ static int __init bpf_key_sig_kfuncs_init(void)
 late_initcall(bpf_key_sig_kfuncs_init);
 #endif /* CONFIG_KEYS */
 
-/* filesystem kfuncs */
-__bpf_kfunc_start_defs();
-
-/**
- * bpf_get_file_xattr - get xattr of a file
- * @file: file to get xattr from
- * @name__str: name of the xattr
- * @value_p: output buffer of the xattr value
- *
- * Get xattr *name__str* of *file* and store the output in *value_ptr*.
- *
- * For security reasons, only *name__str* with prefix "user." is allowed.
- *
- * Return: 0 on success, a negative value on error.
- */
-__bpf_kfunc int bpf_get_file_xattr(struct file *file, const char *name__str,
-				   struct bpf_dynptr *value_p)
-{
-	struct bpf_dynptr_kern *value_ptr = (struct bpf_dynptr_kern *)value_p;
-	struct dentry *dentry;
-	u32 value_len;
-	void *value;
-	int ret;
-
-	if (strncmp(name__str, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
-		return -EPERM;
-
-	value_len = __bpf_dynptr_size(value_ptr);
-	value = __bpf_dynptr_data_rw(value_ptr, value_len);
-	if (!value)
-		return -EINVAL;
-
-	dentry = file_dentry(file);
-	ret = inode_permission(&nop_mnt_idmap, dentry->d_inode, MAY_READ);
-	if (ret)
-		return ret;
-	return __vfs_getxattr(dentry, dentry->d_inode, name__str, value, value_len);
-}
-
-__bpf_kfunc_end_defs();
-
-BTF_KFUNCS_START(fs_kfunc_set_ids)
-BTF_ID_FLAGS(func, bpf_get_file_xattr, KF_SLEEPABLE | KF_TRUSTED_ARGS)
-BTF_KFUNCS_END(fs_kfunc_set_ids)
-
-static int bpf_get_file_xattr_filter(const struct bpf_prog *prog, u32 kfunc_id)
-{
-	if (!btf_id_set8_contains(&fs_kfunc_set_ids, kfunc_id))
-		return 0;
-
-	/* Only allow to attach from LSM hooks, to avoid recursion */
-	return prog->type != BPF_PROG_TYPE_LSM ? -EACCES : 0;
-}
-
-static const struct btf_kfunc_id_set bpf_fs_kfunc_set = {
-	.owner = THIS_MODULE,
-	.set = &fs_kfunc_set_ids,
-	.filter = bpf_get_file_xattr_filter,
-};
-
-static int __init bpf_fs_kfuncs_init(void)
-{
-	return register_btf_kfunc_id_set(BPF_PROG_TYPE_LSM, &bpf_fs_kfunc_set);
-}
-
-late_initcall(bpf_fs_kfuncs_init);
-
 static const struct bpf_func_proto *
 bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 {