From nobody Sun May 24 18:42:24 2026 Received: from mail-wm1-f52.google.com (mail-wm1-f52.google.com [209.85.128.52]) (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 84E5538C2C3 for ; Fri, 22 May 2026 12:41:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.52 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779453684; cv=none; b=GyZtsg9aMk9TNFe5j/o1UWUKrytMbYJ0Fz44Rnth5xcCD5IsGn48GEROM1w3pn52AvaJkdYrauPqXPxWjMMtdDzDx3qQHfQFqRcqG/YOcxK8qsMhgAL1vx63z6Bn3N0J3sA4TK8UbnXJdPKcC9E2O43htKDWn0oodPWHiht55Q4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779453684; c=relaxed/simple; bh=K2Kd3pQcxsqBFlbqqWudAqW3CNfDdi0gezIfNvhDKBY=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=COybQWlHYuLDCLTnBbag0enrY4sTrWdImobbJkWVwrgR0DjeameFXN1722maSuSKOMOg+wzZJdJafU+pV6v/Ol/O10k+ofbBaT9lp+rsBQuGrz/37HCH/lMO8rfmvuvjsG0uUYvnBWtMUWl1tyKy0QOHsAU+zVJ3SZJwyCbP42o= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=W4LPgBew; arc=none smtp.client-ip=209.85.128.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="W4LPgBew" Received: by mail-wm1-f52.google.com with SMTP id 5b1f17b1804b1-48a7fe4f40bso84373855e9.0 for ; Fri, 22 May 2026 05:41:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1779453681; x=1780058481; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=vaGTVnVDkb8ouPe24yBBCJM7yry1NUndZsBJBBuR2jQ=; b=W4LPgBewexWeEE5/ltIbxQ9xpGd5yxTODv6zU2QrXnAR8FEN7Y24ZGdFnmAMD1JoFK Ea2cGZAZQJSs052ypgfo/MDt54K2mRl6nI2OHJX6rsgJm3kLRU6PCBuv8aGhz229eoO/ YSxhu3FvzVker9cYTmRoQm6KXyQFUKcw87mXswTiqkhE/pro5tvE0l99g3IcdLermDRf Oh/clAzoIsGaIECjYkwci8wAtmphtG9OZtKsL9UYdk+G9/gWCIGUalK1KIUHzPEFv716 FR8wX0KItg2aHmJiOHOIcLwSUm9x48ueMUpSmdO3hkDIkKNJ1lUH1KK0GN6H3jKoQNVO 9H6w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779453681; x=1780058481; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=vaGTVnVDkb8ouPe24yBBCJM7yry1NUndZsBJBBuR2jQ=; b=qqkI+L9pQPHDglTZn+5juvIzWiK5BLsjXsvw9ALjv4GtCg0t3VQhuBJObUoeqch9df JO3Gfjt8v5MFTcZBoJk1ApwWqgaXaxVRFGH4AiCU3x/68i+AZxSZObrHHug2ybSgGLHf eqG1KVi67azGyh4wC4xTMXVW6J2BIux/HoZ34FZ4ZjSaNTf2Kjatrm27yd5KCWVl0X6i H//DdaSBs+gGIXEtva9u/zB9b+w/GxUETGbBuiAr+hyKqcRyfeAw3w47gjUvwITVfnWx gpC89aZaH8v1KEz9Tc4g0c9sAiQsvOvKyFQH+YDhTaX0qWByuVIPUkOxFO0yjK9d6Jiq zKFA== X-Forwarded-Encrypted: i=1; AFNElJ8/H1KFl8n5b+X/+++rlJVu7dZpgc51qWrsl62OVVXFHVXhOfyVAxWUDMWr4kgStcHhMPzctP8Zy/gG/14=@vger.kernel.org X-Gm-Message-State: AOJu0YxO/ZU+Ed01sEoxG10hST1+rREfm/HaS/OTfkW+3tDoTRjmn47O DzjesoOn8d81FlYsaa6fBBlcpeeTGNsZZqzFH1jN4v+bdAQHX0uzig1Y X-Gm-Gg: Acq92OF2n6t4KBCdB7oD16vBGq4dl8QCy7CK5h/XlxqCZ5SutUdism9phWSTVhEttJr IssbdIn9PdwVhOxjNn2mq6xlp6G7jVHg64jjbFZIY1nVR4S9Nt4pW5hM6UqyiNyxwFF0ygiFERo xzwk1I/6Cj2TpOzzrCKyJa9DFSapvF3Cp2GsUHPm3HFaKBOhAbIXZHLDvTy2zQq9z9ZcnPY9zF+ tA0yZzJp9/Afti7OFbWkKvJpyPPaXU/ttpn13Rr5jDWVGHLVoWmPOrNbishgaEFzDEDYLvITgPC EPZSuAbsoWTFXe3rKjQtlSx143VLC5PDbJ+OqmYQrMfvl3jNTVt/4gE5rp102v9zdU3CtjgX/OP 1KQYGwSp5KQmfZrBEJxlGAPQ/EEWP383rLijttlS391XQAg+orOWswUp5OP2Wg+5yEIdCGWaDor 90lDitsuif7v32ByzlCURI7VGgJjzoiqu+rTgzN+XY3Yri5/YNeC5+OqyDih3e1HU8jkmTwG/iC H1fGe2mzn7yyCGN5/fDmQWm6hWoYp5cgg1/ynPfRigE06JTUegk5HXUQFE7Fpqx9pS08VGja/4C ww9psU4TlajAZA== X-Received: by 2002:a05:600c:4688:b0:490:4224:e0a2 with SMTP id 5b1f17b1804b1-49042ae265bmr45561905e9.33.1779453680765; Fri, 22 May 2026 05:41:20 -0700 (PDT) Received: from localhost.localdomain ([149.22.234.166]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-490452765f5sm38872395e9.5.2026.05.22.05.41.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 May 2026 05:41:20 -0700 (PDT) From: Himanshu Anand To: martin.lau@linux.dev, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, Himanshu Anand Subject: [PATCH] bpf: Add nelems overflow check in btf_find_field_one() btf_find_field_one() multiplies a u32 nelems accumulator by each nested array level's element count without checking for overflow. The sibling function __btf_resolve_size() already guards against the same overflow pattern (btf.c line 2110). Currently the BTF array verifier (btf_array_resolve) rejects BTF blobs whose total array size would overflow u32, so this code path is not reachable with crafted BTF input on kernels that include that check. Add check_mul_overflow() anyway to keep btf_find_field_one() self-consistent with __btf_resolve_size() and to guard against future changes in the validation ordering. Fixes: 994796c0256c ("bpf: create repeated fields for arrays.") Date: Fri, 22 May 2026 13:41:17 +0100 Message-Id: <20260522124117.13846-1-anand.himanshu17@gmail.com> X-Mailer: git-send-email 2.34.1 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" Signed-off-by: Himanshu Anand --- kernel/bpf/btf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index a62d78581207..b767a9fcf095 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3765,7 +3765,8 @@ static int btf_find_field_one(const struct btf *btf, */ for (i =3D 0; i < MAX_RESOLVE_DEPTH && btf_type_is_array(var_type); i++) { array =3D btf_array(var_type); - nelems *=3D array->nelems; + if (check_mul_overflow(nelems, array->nelems, &nelems)) + return -E2BIG; var_type =3D btf_type_by_id(btf, array->type); } if (i =3D=3D MAX_RESOLVE_DEPTH) --=20 2.34.1