From 04883a079968e6250a4549f6fadb6427c534885e Mon Sep 17 00:00:00 2001 From: Ian Denhardt Date: Tue, 23 Feb 2021 21:15:31 -0500 Subject: [PATCH] tools, bpf_asm: Hard error on out of range jumps Per discussion at [0] this was originally introduced as a warning due to concerns about breaking existing code, but a hard error probably makes more sense, especially given that concerns about breakage were only speculation. [0] https://lore.kernel.org/bpf/c964892195a6b91d20a67691448567ef528ffa6d.camel@linux.ibm.com/T/#t Signed-off-by: Ian Denhardt Signed-off-by: Daniel Borkmann Acked-by: Ilya Leoshkevich Link: https://lore.kernel.org/bpf/a6b6c7516f5d559049d669968e953b4a8d7adea3.1614201868.git.ian@zenhack.net --- tools/bpf/bpf_exp.y | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/bpf/bpf_exp.y b/tools/bpf/bpf_exp.y index 8d48e896be50..8d03e5245da5 100644 --- a/tools/bpf/bpf_exp.y +++ b/tools/bpf/bpf_exp.y @@ -549,9 +549,11 @@ static uint8_t bpf_encode_jt_jf_offset(int off, int i) { int delta = off - i - 1; - if (delta < 0 || delta > 255) - fprintf(stderr, "warning: insn #%d jumps to insn #%d, " + if (delta < 0 || delta > 255) { + fprintf(stderr, "error: insn #%d jumps to insn #%d, " "which is out of range\n", i, off); + exit(1); + } return (uint8_t) delta; }