From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794590408; b=hvnU8Q78kL+MQRlILZb5xw6QHuh1wJkRpA8HVmDB3/iw3jOHboptRba+6N50CebfqGfM 4RO1cH6CLXXWiQS7zei+OBAUWL7hfQ9+Nw/WEvoPjElYoEQWF0bWu0EFuCuYf1ADyF9lD QZiNIfJH0XNv02rlnWFASemcMambdham+PtWsv6k41nkvl0+tJgwOnhBrnfa+HkeVd60q vbkgqjWJpO2WrcMOgrVQh9lWS5HtQtpz4Wb20hDulPwXvX33RBESIrAO5KTcENIVH7ZOp wDhRDHHBRgglZ7WXru9ysPoJAxzJA4SjiCVZz+vQzUQS00JLgUEYMlZLkwo8fTxA57w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794590408; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=uDL5vpi+NXNzTf62HaAP9YEDhGNj8PSQrI8fhrV4Thw=; b=upZonU1SnHWkJcsQFU4PoEXCO8yfVi9rjlbTJkH0NVbxHbW0S6QqTTGQ7F5JwKURoLtI LeAy8A2wTUWXTf2RlWrXJtfc063CAHGV+2axxEPjXvvrevuM/1Me/6DyHScX8pCPeDCXC eddAyFtAvhOmu0+GkXcWhPqMX/5bPRDHt0hzPdHcPCvvw+5orS+cy7MRz0BMkvz5X/xKh DiXGlORvBDuh6w41QSWA9nPO5uo5P8gZzpvjLnLjboBUJj98cRoOGGOqcFVBkZzbVIcwe JM/piY+0j2S0xe5sls9Vazz13t911kbtTWD6RhZhEAkWcPPqxz0fQuSsdTWq3iaShSg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=ucHKn2LO; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8071E606F70D; Fri, 13 Nov 2026 17:20:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=ucHKn2LO Received: by smtp.kernel.org (Postfix) with ESMTPSA id 310AB1F000C4; Fri, 13 Nov 2026 17:20:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794590408; bh=uDL5vpi+NXNzTf62HaAP9YEDhGNj8PSQrI8fhrV4Thw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ucHKn2LOSDjPLqjDBbloHd4s94OC/w9gSUjV93mBNlWW/WmGJHcENki2ja2AC4u1g MAQ5oWoHMVMLkMzvIt2GTuj9aa3AnBIio/FVacxD5d614R2/iNJbs0jyOnW7PdcoOl O9C3KPMC6fbzmmBLRKcgGSgPBr/u440/m37mAqqI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Lorenzo Stoakes (ARM)" , Muchun Song , Barry Song , Muhammad Usama Anjum , "David Hildenbrand (Arm)" , Sasha Levin Subject: [PATCH 6.18 375/686] mm/gup: check for overflow when converting nr_pages to bytes in GUP-fast Date: Fri, 13 Nov 2026 10:48:28 -0500 Message-ID: <20261113153833.624861306@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153820.902362109@linuxfoundation.org> References: <20261113153820.902362109@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Hildenbrand (Arm) [ Upstream commit 21a3888d3d2f87b7f15ccea1f0befd57346fe899 ] The overflow check in gup_fast_fallback() only covers the addition to start. The preceding nr_pages << PAGE_SHIFT can already have truncated the length on 32bit. Users such as RapidIO's rio_dma_transfer() can derive such page counts from a 64-bit userspace length. Let's just check_shl_overflow() to reject any such overflow with -EOVERFLOW early. Fixes: c28b1fc70390 ("mm/gup: reorganize internal_get_user_pages_fast()") Cc: stable@vger.kernel.org Reviewed-by: Lorenzo Stoakes (ARM) Acked-by: Muchun Song Reviewed-by: Barry Song Tested-by: Muhammad Usama Anjum Link: https://patch.msgid.link/20261031-fixes_core-v3-22-d6437171ecc3@kernel.org Signed-off-by: David Hildenbrand (Arm) Signed-off-by: Sasha Levin --- mm/gup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index ac5abfc3dff7e..9ce5c8ef72fad 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -3217,8 +3217,8 @@ static int gup_fast_fallback(unsigned long start, unsigned long nr_pages, might_lock_read(¤t->mm->mmap_lock); start = untagged_addr(start) & PAGE_MASK; - len = nr_pages << PAGE_SHIFT; - if (check_add_overflow(start, len, &end)) + if (check_shl_overflow(nr_pages, PAGE_SHIFT, &len) || + check_add_overflow(start, len, &end)) return -EOVERFLOW; if (end > TASK_SIZE_MAX) return -EFAULT; -- 2.53.0