bpf: Move bpf_get_file_xattr to fs/bpf_fs_kfuncs.c

We are putting all fs kfuncs in fs/bpf_fs_kfuncs.c. Move existing
bpf_get_file_xattr to it.

Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240806230904.71194-2-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/fs/bpf_fs_kfuncs.c b/fs/bpf_fs_kfuncs.c
index 1e6e086..b13d00f 100644 (file)
--- a/fs/bpf_fs_kfuncs.c
+++ b/fs/bpf_fs_kfuncs.c
@@ -8,6 +8,7 @@
 #include <linux/fs.h>
 #include <linux/file.h>
 #include <linux/mm.h>
+#include <linux/xattr.h>
 
 __bpf_kfunc_start_defs();
 
@@ -92,6 +93,42 @@ __bpf_kfunc int bpf_path_d_path(struct path *path, char *buf, size_t buf__sz)
        return len;
 }
 
+/**
+ * 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(bpf_fs_kfunc_set_ids)
@@ -99,6 +136,7 @@ BTF_ID_FLAGS(func, bpf_get_task_exe_file,
             KF_ACQUIRE | KF_TRUSTED_ARGS | KF_RET_NULL)
 BTF_ID_FLAGS(func, bpf_put_file, KF_RELEASE)
 BTF_ID_FLAGS(func, bpf_path_d_path, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_get_file_xattr, KF_SLEEPABLE | KF_TRUSTED_ARGS)
 BTF_KFUNCS_END(bpf_fs_kfunc_set_ids)
 
 static int bpf_fs_kfuncs_filter(const struct bpf_prog *prog, u32 kfunc_id)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index cd09884..d557bb1 100644 (file)
--- 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)
 {