diff options
Diffstat (limited to 'fs/bpf_fs_kfuncs.c')
| -rw-r--r-- | fs/bpf_fs_kfuncs.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/fs/bpf_fs_kfuncs.c b/fs/bpf_fs_kfuncs.c index 08412532db1b..1e36a12b88f7 100644 --- a/fs/bpf_fs_kfuncs.c +++ b/fs/bpf_fs_kfuncs.c @@ -9,6 +9,7 @@ #include <linux/fs.h> #include <linux/fsnotify.h> #include <linux/file.h> +#include <linux/kernfs.h> #include <linux/mm.h> #include <linux/xattr.h> @@ -322,6 +323,39 @@ __bpf_kfunc int bpf_remove_dentry_xattr(struct dentry *dentry, const char *name_ return ret; } +#ifdef CONFIG_CGROUPS +/** + * bpf_cgroup_read_xattr - read xattr of a cgroup's node in cgroupfs + * @cgroup: cgroup to get xattr from + * @name__str: name of the xattr + * @value_p: output buffer of the xattr value + * + * Get xattr *name__str* of *cgroup* and store the output in *value_ptr*. + * + * For security reasons, only *name__str* with prefix "user." is allowed. + * + * Return: length of the xattr value on success, a negative value on error. + */ +__bpf_kfunc int bpf_cgroup_read_xattr(struct cgroup *cgroup, const char *name__str, + struct bpf_dynptr *value_p) +{ + struct bpf_dynptr_kern *value_ptr = (struct bpf_dynptr_kern *)value_p; + u32 value_len; + void *value; + + /* Only allow reading "user.*" xattrs */ + 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; + + return kernfs_xattr_get(cgroup->kn, name__str, value, value_len); +} +#endif /* CONFIG_CGROUPS */ + __bpf_kfunc_end_defs(); BTF_KFUNCS_START(bpf_fs_kfunc_set_ids) |