linux-kernel - [PATCH AUTOSEL 5.2 18/85] swiotlb: fix phys_addr

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190726133936.11177-18-sashal@kernel.org>
Date:   Fri, 26 Jul 2019 09:38:28 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Arnd Bergmann <arnd@...db.de>,
        Stefano Stabellini <sstabellini@...nel.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Sasha Levin <sashal@...nel.org>,
        iommu@...ts.linux-foundation.org
Subject: [PATCH AUTOSEL 5.2 18/85] swiotlb: fix phys_addr_t overflow warning

From: Arnd Bergmann <arnd@...db.de>

[ Upstream commit 9c106119f6538f65bdddb7948a157d90625effa7 ]

On architectures that have a larger dma_addr_t than phys_addr_t,
the swiotlb_tbl_map_single() function truncates its return code
in the failure path, making it impossible to identify the error
later, as we compare to the original value:

kernel/dma/swiotlb.c:551:9: error: implicit conversion from 'dma_addr_t' (aka 'unsigned long long') to 'phys_addr_t' (aka 'unsigned int') changes value from 18446744073709551615 to 4294967295 [-Werror,-Wconstant-conversion]
        return DMA_MAPPING_ERROR;

Use an explicit typecast here to convert it to the narrower type,
and use the same expression in the error handling later.

Fixes: b907e20508d0 ("swiotlb: remove SWIOTLB_MAP_ERROR")
Acked-by: Stefano Stabellini <sstabellini@...nel.org>
Signed-off-by: Arnd Bergmann <arnd@...db.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/xen/swiotlb-xen.c | 2 +-
 kernel/dma/swiotlb.c      | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index d53f3493a6b9..cfbe46785a3b 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -402,7 +402,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
 
 	map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir,
 				     attrs);
-	if (map == DMA_MAPPING_ERROR)
+	if (map == (phys_addr_t)DMA_MAPPING_ERROR)
 		return DMA_MAPPING_ERROR;
 
 	dev_addr = xen_phys_to_bus(map);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 13f0cb080a4d..5f4e1b78babb 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -546,7 +546,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
 	if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
 		dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
 			 size, io_tlb_nslabs, tmp_io_tlb_used);
-	return DMA_MAPPING_ERROR;
+	return (phys_addr_t)DMA_MAPPING_ERROR;
 found:
 	io_tlb_used += nslots;
 	spin_unlock_irqrestore(&io_tlb_lock, flags);
@@ -664,7 +664,7 @@ bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr,
 	/* Oh well, have to allocate and map a bounce buffer. */
 	*phys = swiotlb_tbl_map_single(dev, __phys_to_dma(dev, io_tlb_start),
 			*phys, size, dir, attrs);
-	if (*phys == DMA_MAPPING_ERROR)
+	if (*phys == (phys_addr_t)DMA_MAPPING_ERROR)
 		return false;
 
 	/* Ensure that the address returned is DMA'ble */
-- 
2.20.1