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 221A83C465; Tue, 30 Sep 2025 15:28:51 +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=1759246132; cv=none; b=RdPcrW8CDnjW3PIy5b7XJ9siZ2khlyHJw3XQpC6uVQAybsvZlNfLcvLObjP8pYL6g3HV9hGjHvG8HvRjSqHt0xbmzJoIZVMRLHpOvhpuJVzDjZblbcx98JRhZntz/iBRRl2joN6E+EYr2kQI1CXkUuqEe+70MI1tVPK1DroN9Uo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759246132; c=relaxed/simple; bh=Z0huMTC1EBQm4jf0JufU2I1LHit+R1qfdBGNK7XoMYY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tbUwdZNg9hEsOF4zD3UNqaVVcrYfvvWf47UYWvSJfRltVj5G+ygEUuVb1cKECYsjwGibtupxn/tl5PeWc+2SSeAdF6W7PfdGhaHRuRsJxO3rYYWbfipSCcGtf8FBUH1l3nWxr5TmVNKeDHrjZhkZYLUKgqiz6G2/sCyfFIHpvHw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=djDzfiPu; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="djDzfiPu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52927C4CEF0; Tue, 30 Sep 2025 15:28:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1759246131; bh=Z0huMTC1EBQm4jf0JufU2I1LHit+R1qfdBGNK7XoMYY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=djDzfiPubhcie6ZNqabsa4kO4KHgoW8OniRAwz69VllQklU49ex/oyHEKcIjQQiw/ CqOtyZEDCAJwGiOus4F6ATbkM3biLlRv3cgxcsdXWbBPkYL4T0oVZp0XuJ5niP4BOT XJH4snUZqui+TIzFOirK3oZi/bSOxooDPzAmtYsM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, kernel test robot , syzbot+a9ed3d9132939852d0df@syzkaller.appspotmail.com, Alexei Starovoitov , Jiri Olsa , Daniel Borkmann , Paul Chaignon , Sasha Levin Subject: [PATCH 6.12 34/89] bpf: Check the helper function is valid in get_helper_proto Date: Tue, 30 Sep 2025 16:47:48 +0200 Message-ID: <20250930143823.331350367@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250930143821.852512002@linuxfoundation.org> References: <20250930143821.852512002@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiri Olsa [ Upstream commit e4414b01c1cd9887bbde92f946c1ba94e40d6d64 ] kernel test robot reported verifier bug [1] where the helper func pointer could be NULL due to disabled config option. As Alexei suggested we could check on that in get_helper_proto directly. Marking tail_call helper func with BPF_PTR_POISON, because it is unused by design. [1] https://lore.kernel.org/oe-lkp/202507160818.68358831-lkp@intel.com Reported-by: kernel test robot Reported-by: syzbot+a9ed3d9132939852d0df@syzkaller.appspotmail.com Suggested-by: Alexei Starovoitov Signed-off-by: Jiri Olsa Signed-off-by: Daniel Borkmann Acked-by: Paul Chaignon Acked-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20250814200655.945632-1-jolsa@kernel.org Closes: https://lore.kernel.org/oe-lkp/202507160818.68358831-lkp@intel.com Signed-off-by: Sasha Levin --- kernel/bpf/core.c | 5 ++++- kernel/bpf/verifier.c | 2 +- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 9380e0fd5e4af..1f51c8f20722e 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2953,7 +2953,10 @@ EXPORT_SYMBOL_GPL(bpf_event_output); /* Always built-in helper functions. */ const struct bpf_func_proto bpf_tail_call_proto = { - .func = NULL, + /* func is unused for tail_call, we set it to pass the + * get_helper_proto check + */ + .func = BPF_PTR_POISON, .gpl_only = false, .ret_type = RET_VOID, .arg1_type = ARG_PTR_TO_CTX, diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 24ae8f33e5d76..6e22abf3326b6 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -10465,7 +10465,7 @@ static int get_helper_proto(struct bpf_verifier_env *env, int func_id, return -EINVAL; *ptr = env->ops->get_func_proto(func_id, env->prog); - return *ptr ? 0 : -EINVAL; + return *ptr && (*ptr)->func ? 0 : -EINVAL; } static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn, -- 2.51.0