From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B88B6471401; Tue, 21 Jul 2026 17:51:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784656287; cv=none; b=Wq4G9PcE5WXW6fenwOopetCcuNfARK8sRgmB6LyBJxm5PrmCs77O52QyZP65qXY4LDUQrLI14UWxPT+5RUhc2NyzWQmdmTNlMybtYm+S6tTv4ov5hp8f3jL3F9iPmcLsD5KrLA5vTTixke+VcZit3Y81CQftar6WLETsMrnWQrY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784656287; c=relaxed/simple; bh=t/uOhgY5yYrk3sHvarFI3GZ4dI1zxyyZmCvhFXMkhcg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tjp+aXEUSlJo2DGiis0ZfPXHmQofwJ2NJpNYgRsTIBmdAoRdVSCzs5YNTi1TnV2rEZ6hK2jVkS99jVBPIkc3DRHkBGvLNPPZ33d8PYCjnv26+JhiZ6bDte48ivv1LszO/fLpIkYNjdQWvjWkU3mslGOd8FqDZ5WUV5F+GklAQio= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=WteMVfru; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="WteMVfru" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2AA3A1F000E9; Tue, 21 Jul 2026 17:51:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784656286; bh=zTFty6OrDZ9tebjrXfRrmVQOVzkQJdXZEqDBWmRfLGQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=WteMVfruB1kS6i47mgJMz6jAYREbeABk9TlYMRWMfUwBKThMIKaXioajFmSESReC5 xwSzFFxmymNHKsdBz32A7fAqoJKekwi79JRO47NUho8hErmXSBAsQi2NUtXpSO6dFd /9/viMAJccCG3j/BTiOzXWqOPa+KJtjG8GCImGbM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, sashiko , Daniel Borkmann , Alexei Starovoitov , Sasha Levin Subject: [PATCH 6.18 0287/1611] libbpf: Skip hash computation when loader generation failed Date: Tue, 21 Jul 2026 17:06:43 +0200 Message-ID: <20260721152521.516060431@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152514.750365251@linuxfoundation.org> References: <20260721152514.750365251@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Borkmann [ Upstream commit 3c5e2f1a85844abbb65df4694f5ebad0a13e219c ] bpf_gen__finish() calls compute_sha_update_offsets() gated only on the gen_hash option, without first consulting gen->error. On a failed generation this is buggy: a failed realloc_data_buf() sets gen->data_start to NULL (leaving gen->data_cur dangling), so compute_sha_update_offsets() runs libbpf_sha256() over a NULL buffer with a bogus length; a failed realloc_insn_buf() likewise sets gen->insn_start to NULL and the hash immediates get patched through that NULL base. The computed program is discarded in either case, since the following "if (!gen->error)" block does not publish opts->insns once an error is set. Thus, skip the hash pass when generation has already failed. Fixes: ea923080c145 ("libbpf: Embed and verify the metadata hash in the loader") Reported-by: sashiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/r/20260529094119.307264-2-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- tools/lib/bpf/gen_loader.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/tools/lib/bpf/gen_loader.c b/tools/lib/bpf/gen_loader.c index cd5c2543f54d85..b2e8b4224640f8 100644 --- a/tools/lib/bpf/gen_loader.c +++ b/tools/lib/bpf/gen_loader.c @@ -398,13 +398,12 @@ int bpf_gen__finish(struct bpf_gen *gen, int nr_progs, int nr_maps) blob_fd_array_off(gen, i)); emit(gen, BPF_MOV64_IMM(BPF_REG_0, 0)); emit(gen, BPF_EXIT_INSN()); - if (OPTS_GET(gen->opts, gen_hash, false)) - compute_sha_update_offsets(gen); - - pr_debug("gen: finish %s\n", errstr(gen->error)); if (!gen->error) { struct gen_loader_opts *opts = gen->opts; + if (OPTS_GET(opts, gen_hash, false)) + compute_sha_update_offsets(gen); + opts->insns = gen->insn_start; opts->insns_sz = gen->insn_cur - gen->insn_start; opts->data = gen->data_start; @@ -419,6 +418,7 @@ int bpf_gen__finish(struct bpf_gen *gen, int nr_progs, int nr_maps) bpf_insn_bswap(insn++); } } + pr_debug("gen: finish %s\n", errstr(gen->error)); return gen->error; } -- 2.53.0