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 23D953B19B9; Sat, 17 Oct 2026 17:29:56 +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=1792258197; cv=none; b=fZHeuhW+Hv1QoM3+oQLZiX0MJRxLbFYbB49pn8LkGwOK1x1AccBSL3xjW5YQslrD1cxpIlx/94AS4n/+zbTjWFGG3+oyh720BCQPo6HiHC1vgMzadclI2vGRVsS1POiBfHY4kFf1JMN5RhJ8cS6R6Opw0EAWc36vbgHn2ZoQf0Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792258197; c=relaxed/simple; bh=K95FdjEFiT8DjQnu5MCJocg1bsUtDTeV5NpNE5HpoT4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jXiRs3XnqdDYUHqCHp1HCk6yiAcQgYoTzVusDs53BsTasm+k+dlP+REq794q4nNSaMU/qrgpJuT5BP8/dwD0Ri/+9aBVRTZZ7YnZn1nbbPnssB8dkQumVuN8Tt4uH2avgmcSeu/5lQXYNXRfiV5DYyysCpDxVbc66fGdUEhnr8Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=IAVccKSS; 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="IAVccKSS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 773241F000C4; Sat, 17 Oct 2026 17:29:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792258196; bh=AQKFkkw3mP/B3iKsFGKJZNVRtl3SY3qs2LAitn5Ty+U=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=IAVccKSSEnOy4XoG+7JzeJV9x//WjlPPYGQ2WsJhG1tcZ9YUYmcX46ML95Nv4ORM2 /nnK1Rijj7DNZk7DTT/wYUXD4fbTFxIrqNAQkvaOQ5lPgYNxn0UvrSG0stsr28mvfK oqB3yq6RGhwqW155JJbczYuKfF1YVRCxdk0sEb/8= 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 6.6 0797/1674] bpf: Check the helper function is valid in get_helper_proto Date: Sat, 17 Oct 2026 17:51:09 +0200 Message-ID: <20261017160451.565030211@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160431.119607952@linuxfoundation.org> References: <20261017160431.119607952@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 6.6-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 3fc818987ef0e..5dee9d2c0420f 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2962,7 +2962,10 @@ 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 958da74f9045e..68e9660405342 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -10081,7 +10081,7 @@ 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, -- 2.53.0