From 7384893d970ea114952aef54ad7e3d7d2ca82d4f Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Tue, 16 Sep 2025 23:52:56 +0200 Subject: bpf: Allow uprobe program to change context registers Currently uprobe (BPF_PROG_TYPE_KPROBE) program can't write to the context registers data. While this makes sense for kprobe attachments, for uprobe attachment it might make sense to be able to change user space registers to alter application execution. Since uprobe and kprobe programs share the same type (BPF_PROG_TYPE_KPROBE), we can't deny write access to context during the program load. We need to check on it during program attachment to see if it's going to be kprobe or uprobe. Storing the program's write attempt to context and checking on it during the attachment. Acked-by: Andrii Nakryiko Signed-off-by: Jiri Olsa Link: https://lore.kernel.org/r/20250916215301.664963-2-jolsa@kernel.org Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/bpf.h b/include/linux/bpf.h index ba3a3be7eb2a..ea2ed6771cc6 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1639,6 +1639,7 @@ struct bpf_prog_aux { bool priv_stack_requested; bool changes_pkt_data; bool might_sleep; + bool kprobe_write_ctx; u64 prog_array_member_cnt; /* counts how many times as member of prog_array */ struct mutex ext_mutex; /* mutex for is_extended and prog_array_member_cnt */ struct bpf_arena *arena; -- cgit v1.2.3