format_disasm_line() strips trailing newlines from the disassembly it
stores, as diag_print_insn_context() adds its own. Since
commit 483a1bb0b6cf8 ("bpf: Do not print a newline after disassembly in
bpf_verbose_insn()"), print_bpf_insn() does not emit one, so there is
nothing left to strip.The strnlen() resync of the seq_buf length only existed so the loop could index the buffer safely after an overflow, and the second termination only restored the NUL that seq_buf_pop() does not write. Remove all of it, keeping a single seq_buf_terminate(). Build tested ARCH=x86_64 defconfig with GCC 16.2.0 and CONFIG_BPF_SYSCALL=y. Assisted-by: LLM Signed-off-by: Kees Cook <[email protected]> --- kernel/bpf/diagnostics.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/kernel/bpf/diagnostics.c b/kernel/bpf/diagnostics.c index 594cf3c8b74c..8f64bfd9afee 100644 --- a/kernel/bpf/diagnostics.c +++ b/kernel/bpf/diagnostics.c @@ -632,10 +632,6 @@ static void format_disasm_line(struct bpf_verifier_env *env, int insn_idx, print_bpf_insn(&cbs, insn, env->allow_ptr_leaks); seq_buf_terminate(&ctx.seq); - ctx.seq.len = strnlen(line->text, sizeof(line->text)); - while (ctx.seq.len && line->text[ctx.seq.len - 1] == '\n') - seq_buf_pop(&ctx.seq); - seq_buf_terminate(&ctx.seq); line->valid = true; } -- 2.34.1
