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 28E171D14F8; Wed, 2 Oct 2024 14:07:42 +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=1727878062; cv=none; b=GwxCLw4huW3nAW1VXhqEMDO65ZKT0Af2tMXJTBjl/m+ccgOyTRWYq6wDoo2m3v6fV6tF3sQ/XHlYFXHiL0bmRQJr6BMF8K0yCmPGK7Gw/bQsgBPswMdfh2boJn/0J6n9wIz471h897spLB0TBIoCPduQcM8Y2uIy61W+vrS9spM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727878062; c=relaxed/simple; bh=P8Tu+dTEvq5/AqIIT3a+CRmXgavXcrLcXR49KHXkpyg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XgxUopNxXCDNY/G0bYmtCorgozt2qYfGzzMn1D52tu5jvU4g39DBDY7ufbRJ/427kTyb6Og/VZC2OOCAiVFRRTURnbsp0kuwlH76KeEbfOk18fl898GefX07BXexSl9pOVJ6K0rIMRdU4Frlpg2ENBDSiWaTB4DvRehshzSX58Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=y3fDQW7M; 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="y3fDQW7M" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A80BAC4CEC2; Wed, 2 Oct 2024 14:07:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1727878062; bh=P8Tu+dTEvq5/AqIIT3a+CRmXgavXcrLcXR49KHXkpyg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=y3fDQW7MNwnRGHL8Nhq+40v3GrwNQC0VSTAO7RkdDk+rMAhIx5dqAX1fA3essm3lj 0atdrIGu437x8Nw3+AvbG9UHUTOZ25YbL+vVRGoq+3bEZJGw9k9+wet6KBoAzPw/ej LUFDX+wI7eRi5EwLS+KBwjqNSp7M5ETFEJwCa3Sw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Sasha Levin Subject: [PATCH 6.10 288/634] bpf: Fix bpf_strtol and bpf_strtoul helpers for 32bit Date: Wed, 2 Oct 2024 14:56:28 +0200 Message-ID: <20241002125822.476966965@linuxfoundation.org> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241002125811.070689334@linuxfoundation.org> References: <20241002125811.070689334@linuxfoundation.org> User-Agent: quilt/0.67 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 6.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Borkmann [ Upstream commit cfe69c50b05510b24e26ccb427c7cc70beafd6c1 ] The bpf_strtol() and bpf_strtoul() helpers are currently broken on 32bit: The argument type ARG_PTR_TO_LONG is BPF-side "long", not kernel-side "long" and therefore always considered fixed 64bit no matter if 64 or 32bit underlying architecture. This contract breaks in case of the two mentioned helpers since their BPF_CALL definition for the helpers was added with {unsigned,}long *res. Meaning, the transition from BPF-side "long" (BPF program) to kernel-side "long" (BPF helper) breaks here. Both helpers call __bpf_strtoll() with "long long" correctly, but later assigning the result into 32-bit "*(long *)" on 32bit architectures. From a BPF program point of view, this means upper bits will be seen as uninitialised. Therefore, fix both BPF_CALL signatures to {s,u}64 types to fix this situation. Now, changing also uapi/bpf.h helper documentation which generates bpf_helper_defs.h for BPF programs is tricky: Changing signatures there to __{s,u}64 would trigger compiler warnings (incompatible pointer types passing 'long *' to parameter of type '__s64 *' (aka 'long long *')) for existing BPF programs. Leaving the signatures as-is would be fine as from BPF program point of view it is still BPF-side "long" and thus equivalent to __{s,u}64 on 64 or 32bit underlying architectures. Note that bpf_strtol() and bpf_strtoul() are the only helpers with this issue. Fixes: d7a4cb9b6705 ("bpf: Introduce bpf_strtol and bpf_strtoul helpers") Reported-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/481fcec8-c12c-9abb-8ecb-76c71c009959@iogearbox.net Link: https://lore.kernel.org/r/20240913191754.13290-1-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- kernel/bpf/helpers.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 7268370600f6e..ffabd06be1240 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -517,7 +517,7 @@ static int __bpf_strtoll(const char *buf, size_t buf_len, u64 flags, } BPF_CALL_4(bpf_strtol, const char *, buf, size_t, buf_len, u64, flags, - long *, res) + s64 *, res) { long long _res; int err; @@ -542,7 +542,7 @@ const struct bpf_func_proto bpf_strtol_proto = { }; BPF_CALL_4(bpf_strtoul, const char *, buf, size_t, buf_len, u64, flags, - unsigned long *, res) + u64 *, res) { unsigned long long _res; bool is_negative; -- 2.43.0