bpf: Add bpf_copy_from_user_str kfunc

This adds a kfunc wrapper around strncpy_from_user, which can be called from sleepable BPF programs. This matches the non-sleepable 'bpf_probe_read_user_str' helper except it includes an additional 'flags' param, which allows consumers to clear the entire destination buffer on success or failure. Signed-off-by: Jordan Rome <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
libbpf · Sep 2, 2024 · 07d9690 · 07d9690
1 parent 0db3e34
commit 07d9690
Showing 1 changed file with 9 additions and 0 deletions.
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
@@ -7512,4 +7512,13 @@ struct bpf_iter_num {
 	__u64 __opaque[1];
 } __attribute__((aligned(8)));
 
+/*
+ * Flags to control BPF kfunc behaviour.
+ *     - BPF_F_PAD_ZEROS: Pad destination buffer with zeros. (See the respective
+ *       helper documentation for details.)
+ */
+enum bpf_kfunc_flags {
+	BPF_F_PAD_ZEROS = (1ULL << 0),
+};
+
 #endif /* _UAPI__LINUX_BPF_H__ */