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=1794591189; b=YmrQgneBBifPzch7lN/Mfn+UIJ97GdDTJ6i2uAZPcxdswKDwG4TU40qLI0FS/fb0m51x KSabiu4zb3O8CQ4X/z18vK31IPXbLmO6ySUVviOsLTWY9c5EMqVWXP1VyzJyT6Vr6xYeP E7MLrN4lSaghbCz0f/A94u26aCQgoucyN8ZRuCh5M/tb3ckxmg2OhO59Jt3BOsvaPiDBx j9HbVBTZOACWDpVxLVxZLt1j4DvoujkuLwNe8h0YBDvBwIyKbacH+zgc9lBPnXEIeMWFv A4aKBX2Pgkwr0rPAGgKD2px0Rkm+ZSzasPO3BSZsm/x1SYnqptncCwB/97UNKnpMTCQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794591189; 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=kJDdb/Q+uDwkWTsreFdZLP0NTMcm3uA0ua6YO5OeaQg=; b=dpCZPg3xzxw+btnOvldwexmTZxLdweQacCZM6X99o0eMLgY5MGvtcSRAFbsGq5I83EvJ UCkSWupQkhiwc5gC0CTxiqkQwGFjJJqgbijzd0uCnUcX72kQMlyLxfBJVrAzO2zYywcOP c6Ga+60BteiTPHosb/8cKWS2HKcFKC3WsSoUxDCHMz+z4aq0xT5FbM80tzPL0sjwtNeh0 swzWNpHz5WbfoAu/uu96Ryn4/L1vUr4q6iw+/5NZ/Zv83syaWZXiCXvKAO7ozebCbNI/8 bn/FJ0BISel12Htf6TXMDAbOIo0vtzcFUm1mKPhTDUIGc2kKfyKFRNgWB+OfuV9l9Sg== 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=b9bSWin8; 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 410996075E09; Fri, 13 Nov 2026 17:33:09 +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=b9bSWin8 Received: by smtp.kernel.org (Postfix) with ESMTPSA id E5F471F000C5; Fri, 13 Nov 2026 17:33:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794591189; bh=kJDdb/Q+uDwkWTsreFdZLP0NTMcm3uA0ua6YO5OeaQg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=b9bSWin8A22tfCji/85Oi9ULnYDRvqaxyICOXC3txiBxdsoqJcg76dVxN+/dSmhsP fvmq8ClAK/LULyuSyJLVr4aHiD4wlk5bx0Hk7Oyiulq50dv2t/4qR18JdcqtLfEqcl leHjpxANA1J6knsGMe5yUNEJHaafltrL1MxfV6gE= 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 6.12 325/670] mm/gup: check for overflow when converting nr_pages to bytes in GUP-fast Date: Fri, 13 Nov 2026 10:48:09 -0500 Message-ID: <20261113153822.900675755@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153811.177190860@linuxfoundation.org> References: <20261113153811.177190860@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-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 c3df6f7d0bf2c..0e1a0c6c5f213 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -3458,8 +3458,8 @@ 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