From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 9157C13B785; Tue, 16 Jan 2024 19:53:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705434812; cv=none; b=hajMgtvMuLgWRc4GWqcWQM7HMNu00lcrtKqS9uFU1UOQNEjpikC0OntmwE24wkbtopLaScUuX5Kawkv6nOrlUEpETdHs/uPXnj5hbYeCRsYN08Y1wNsMr9J07gVprjeBblPiMGyjyk50Ce+QhM2vhpkMbb8KE9A1c/DgwZUB5PI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705434812; c=relaxed/simple; bh=sQ0wS/58+NtRgomC/D/pCetGutfZh6iT0unc47ZnxnU=; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID: X-Mailer:In-Reply-To:References:MIME-Version:X-stable: X-Patchwork-Hint:X-stable-base:Content-Transfer-Encoding; b=fcj/ZGPPrMfuYu7JJBKP+PCzTJHQHxt0wTrJd+yRL0ohFrGuDuoOhDsKrrz8M4E6jvPovEFJd9+tWbLyH9trL1ytXXz0YFkXQ/CI20H4yg/N2T/xbqOPrHbzdcIabt0wXmuTqNyWJLkgGrmGb419kv9kxu29xFENpVRHZdZEGR4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=M3S9b5o+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="M3S9b5o+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6B1B1C43390; Tue, 16 Jan 2024 19:53:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1705434812; bh=sQ0wS/58+NtRgomC/D/pCetGutfZh6iT0unc47ZnxnU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M3S9b5o+9Vy5k3YPaF+e+Ft709urC1rM0Om5JEIkZSJWcIwioEGeeBb0nwkTO77KQ NGV2y2HHz8vu48HLMby20zOVEEhLeVgQCprMQFqvODgb80Thl/bpJoxhJAqoI0l7Kk hbcTYFfZ2vwB6asSfxRJoMUgy8+/P5C2wXX4eVL3YmQdjyIKUIgON20HnmcLsJcsSE T3++krKHr6RlUPTFeqhSovRk1Xx+Yfc5DKU4tzzrHK44bwnz3/jpMxRT3JDoaXCCe7 w9e++YBY2J7nQpoJS0jeQXqOsYwElFqmknwgXTi6Fu08405fhozo82MFtPJpFAQi/n GVVRWYQMFkDaw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Mingyi Zhang , Xin Liu , Changye Wu , Andrii Nakryiko , Daniel Borkmann , Sasha Levin , ast@kernel.org, bpf@vger.kernel.org Subject: [PATCH AUTOSEL 6.6 089/104] libbpf: Fix NULL pointer dereference in bpf_object__collect_prog_relos Date: Tue, 16 Jan 2024 14:46:55 -0500 Message-ID: <20240116194908.253437-89-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240116194908.253437-1-sashal@kernel.org> References: <20240116194908.253437-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.12 Content-Transfer-Encoding: 8bit From: Mingyi Zhang [ Upstream commit fc3a5534e2a8855427403113cbeb54af5837bbe0 ] An issue occurred while reading an ELF file in libbpf.c during fuzzing: Program received signal SIGSEGV, Segmentation fault. 0x0000000000958e97 in bpf_object.collect_prog_relos () at libbpf.c:4206 4206 in libbpf.c (gdb) bt #0 0x0000000000958e97 in bpf_object.collect_prog_relos () at libbpf.c:4206 #1 0x000000000094f9d6 in bpf_object.collect_relos () at libbpf.c:6706 #2 0x000000000092bef3 in bpf_object_open () at libbpf.c:7437 #3 0x000000000092c046 in bpf_object.open_mem () at libbpf.c:7497 #4 0x0000000000924afa in LLVMFuzzerTestOneInput () at fuzz/bpf-object-fuzzer.c:16 #5 0x000000000060be11 in testblitz_engine::fuzzer::Fuzzer::run_one () #6 0x000000000087ad92 in tracing::span::Span::in_scope () #7 0x00000000006078aa in testblitz_engine::fuzzer::util::walkdir () #8 0x00000000005f3217 in testblitz_engine::entrypoint::main::{{closure}} () #9 0x00000000005f2601 in main () (gdb) scn_data was null at this code(tools/lib/bpf/src/libbpf.c): if (rel->r_offset % BPF_INSN_SZ || rel->r_offset >= scn_data->d_size) { The scn_data is derived from the code above: scn = elf_sec_by_idx(obj, sec_idx); scn_data = elf_sec_data(obj, scn); relo_sec_name = elf_sec_str(obj, shdr->sh_name); sec_name = elf_sec_name(obj, scn); if (!relo_sec_name || !sec_name)// don't check whether scn_data is NULL return -EINVAL; In certain special scenarios, such as reading a malformed ELF file, it is possible that scn_data may be a null pointer Signed-off-by: Mingyi Zhang Signed-off-by: Xin Liu Signed-off-by: Changye Wu Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20231221033947.154564-1-liuxin350@huawei.com Signed-off-by: Sasha Levin --- tools/lib/bpf/libbpf.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 96ff1aa4bf6a..de08b920a149 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4251,6 +4251,8 @@ bpf_object__collect_prog_relos(struct bpf_object *obj, Elf64_Shdr *shdr, Elf_Dat scn = elf_sec_by_idx(obj, sec_idx); scn_data = elf_sec_data(obj, scn); + if (!scn_data) + return -LIBBPF_ERRNO__FORMAT; relo_sec_name = elf_sec_str(obj, shdr->sh_name); sec_name = elf_sec_name(obj, scn); -- 2.43.0