From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f179.google.com (mail-pl1-f179.google.com [209.85.214.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DC93A27E045 for ; Sun, 26 Apr 2026 19:17:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777231031; cv=none; b=js3mAsnTS4rH8Rh+DwSZsi1rxkKBX2LrmMymqAXkXRT/mJJjWgSP1aY3t2JL9YfkgN8j6Rk4fkPr24OZ79cF2b6+eioSRQkfSAQL2QsaFmwQDthNs1HgisZ+ZyHowOP41bySNtyJl/x5/17qMDmToPi/gWtWizEL+TSSWldmfHU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777231031; c=relaxed/simple; bh=hx4muqT329gvnq8emb2sJIUT4hEB8hYF9W8WijtuD5A=; h=Mime-Version:Content-Type:Date:Message-Id:To:Cc:Subject:From: References:In-Reply-To; b=IkuKo+uC+c4qLJc5wWEp075JXSdFZnUbMFFVSMwci+tBrDmxHw3Fvqe7RxvrrTIhG9O06wTf+bMUk64M15m3qHM35oXuNFOUmjonOTLq7fdHFbVeYXGwvOX/Ptko1rLOgMgutJcGxY8oNB995JDNt2EAZhcDzS1kfPcXez3jWXA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=etsalapatis.com; spf=pass smtp.mailfrom=etsalapatis.com; dkim=pass (2048-bit key) header.d=etsalapatis-com.20251104.gappssmtp.com header.i=@etsalapatis-com.20251104.gappssmtp.com header.b=RMMLJEf4; arc=none smtp.client-ip=209.85.214.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=etsalapatis.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=etsalapatis.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=etsalapatis-com.20251104.gappssmtp.com header.i=@etsalapatis-com.20251104.gappssmtp.com header.b="RMMLJEf4" Received: by mail-pl1-f179.google.com with SMTP id d9443c01a7336-2b7adb38d65so33149185ad.2 for ; Sun, 26 Apr 2026 12:17:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=etsalapatis-com.20251104.gappssmtp.com; s=20251104; t=1777231029; x=1777835829; darn=vger.kernel.org; h=in-reply-to:references:from:subject:cc:to:message-id:date :content-transfer-encoding:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=TSblK11nZsAuu6dBblEvTDaeDGn9LCh73TEkAHVfyjE=; b=RMMLJEf4590MoUilHmvsjowveElP5vUUM7ThmkzaQNIPnFGb6xRRFUB7XIdrze1eqd e3b8zBD+NYV4BavwzAGXfABrjopDPloRb55Ilp7Ovwcw4EaVoSCQX4YsK+qRO5J8Q48i gXDEEW+pnp8ajEndqzlIwCVf+3HRgWiIk+wX5GvavmVeHySC2g4ugY7zt/wMkfAajOqF imPS4GU/iHJApRfWVxFRjLeI2FasFVJQ1DpGjNuFCnhFgE7sT//RAoa4nftamOFz5UuS Qhyxm7AQpPdazbnEGBCDXbX845AMievO/W40Wb8jymSan3rfxwFncrTgfyduo8Cfw9Je SiKw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777231029; x=1777835829; h=in-reply-to:references:from:subject:cc:to:message-id:date :content-transfer-encoding:mime-version:x-gm-gg:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=TSblK11nZsAuu6dBblEvTDaeDGn9LCh73TEkAHVfyjE=; b=lzNKzZF60W1zX51lIoFAO+0Kq1IMJj86BX2s1UoAu0daPT20Vn3UrgJyO9WOuuUT8R SLq3vZVr/E8FofC52pB1c2QkZzKvDiprtH1Zcn+ZVSmyzO/zqeeAGQy5ZrkJZohJQSFG FsK8uonqFfkS1HtD04aneyEyV9h8L89GtEEFrSXqFjbx9EdtXNJx3J/jFraQlgd0GqKi loRyy3KJYegPpnmpGsrwXZYzvlx61/0fvDG01NUNHi9lm31TdKoFztu0Kq672IJp0Pc6 /kQZQSDnOYt62G5US+HrI7E+eM9Lhd0v8v4bXn1dm2XCRLFlF4GvfLgsRsVjTvyUG2dW s+xw== X-Forwarded-Encrypted: i=1; AFNElJ/3XKv9/tQzV7QH20WMHBPj8EDRrKXw/ENl5N51eDJ0Fb5DYuKvfhceTTaPvq26pWDZd4vazDES9jl6skg=@vger.kernel.org X-Gm-Message-State: AOJu0YwWHfVoBMhTDOkoYCCYYdR7dDohTy892nOwluQ1UtD/J8yzjBii Mk80OLJaL8uUksabmqdoHY8fEpOGk5wHaYK1KrAueF2jilw3IQ6nnR2PlqI5sDUYqA8= X-Gm-Gg: AeBDievA1VIm1h6drNTFOrmO6tzzexD/JyaI/zOGySLCJyGvngIGo0yyg+Jxsckg/kA x6UDBmBq3PcYtIKjou4Dt6X2GSkEcfKlDW/GLgI6k7oOSAR3YibqZOe98O0NGNC7wzMQRsfm353 YzlPEgHYoSgQhlC+L1dgUIcaiGz/fXXI/99lwVLEgQSlIJwodlf/bL4ygLbXxoyTGooJ2qzApqM 57ipZQr5Q9wVM1UHgzCMy1lWQVcjmS5T6+E8QzUojrGAsV0cRIRvoNFTdvvjGzww7yBRYlMH7lj S2gBXICOJ1rh6anotkZVPJ3x0zq0rvOn3zYevWnC96QrIEoADIEP/BeNBccs8veCn0kSwdzFZ8l dHmMVNc3nBpT8Yn5BWOseyhJERNPxGxl6YG29uCUCmmKFxzZRzVb/S1JCazK6H5jWA5pXrb/k2Q W5SwsK4ooAm4I+hTHo8mekNk2xr2v2 X-Received: by 2002:a17:903:2acb:b0:2b4:6398:6aa2 with SMTP id d9443c01a7336-2b5f9f3a802mr459892015ad.27.1777231029189; Sun, 26 Apr 2026 12:17:09 -0700 (PDT) Received: from localhost ([2604:3d08:487d:cd00::2af6]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2b5fab2114bsm270988425ad.60.2026.04.26.12.17.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 26 Apr 2026 12:17:08 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Sun, 26 Apr 2026 15:17:08 -0400 Message-Id: To: "Junyoung Jang" , , , , , Cc: , , , , , , , Subject: Re: [PATCH bpf v2] bpf: Fix off-by-one boundary validation in arena direct-value access From: "Emil Tsalapatis" X-Mailer: aerc 0.21.0-0-g5549850facc2 References: <2026042614-scowling-hankie-f84b@gregkh> <20260426172505.1947915-1-graypanda.inzag@gmail.com> In-Reply-To: <20260426172505.1947915-1-graypanda.inzag@gmail.com> On Sun Apr 26, 2026 at 1:25 PM EDT, Junyoung Jang wrote: > BPF_MAP_TYPE_ARENA accepts BPF_PSEUDO_MAP_VALUE offsets at exactly > the end of the arena mapping (off =3D=3D arena_size). The boundary check > in arena_map_direct_value_addr() uses `>` instead of `>=3D`, which > incorrectly allows a one-past-end pointer to be accepted. > > Change the condition to `>=3D` to correctly reject offsets that fall > outside the valid arena user_vm range. > > Fixes: 317460317a02 ("bpf: Introduce bpf_arena.") > Signed-off-by: Junyoung Jang > --- Reviewed-by: Emil Tsalapatis > kernel/bpf/arena.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c > index 802656c6fd3c..49a8f7b1beef 100644 > --- a/kernel/bpf/arena.c > +++ b/kernel/bpf/arena.c > @@ -511,7 +511,7 @@ static int arena_map_direct_value_addr(const struct b= pf_map *map, u64 *imm, u32 > { > struct bpf_arena *arena =3D container_of(map, struct bpf_arena, map); > =20 > - if ((u64)off > arena->user_vm_end - arena->user_vm_start) > + if ((u64)off >=3D arena->user_vm_end - arena->user_vm_start) > return -ERANGE; > *imm =3D (unsigned long)arena->user_vm_start; > return 0;