From: Liang Wang
maillist inclusion
category: bugfix
issue: #I4LRGQ
CVE: NA
Reference: https://lore.kernel.org/stable/20210731025057.78825-1-wangliang101@huawei.co...
--------------------------------
The physical address may exceed 32 bits on 32-bit systems with more than
32 bits of physcial address,use PFN_PHYS() in devmem_is_allowed(), or the
physical address may overflow and be truncated.
We found this bug when mapping a high addresses through devmem tool, when
CONFIG_STRICT_DEVMEM is enabled on the ARM with ARM_LPAE and devmem is
used to map a high address that is not in the iomem address range, an
unexpected error indicating no permission is returned.
This bug was initially introduced from v2.6.37, and the function was moved
to lib when v5.11.
Link: https://lkml.kernel.org/r/20210731025057.78825-1-wangliang101@huawei.com
Fixes: 087aaffcdf9c ("ARM: implement CONFIG_STRICT_DEVMEM by disabling access to RAM via /dev/mem")
Fixes: 527701eda5f1 ("lib: Add a generic version of devmem_is_allowed()")
Signed-off-by: Liang Wang
Reviewed-by: Luis Chamberlain
Cc: Palmer Dabbelt
Cc: Greg Kroah-Hartman
Cc: Russell King
Cc: Liang Wang
Cc: Xiaoming Ni
Cc: Kefeng Wang
Cc: [2.6.37+]
Signed-off-by: Andrew Morton
Signed-off-by: Stephen Rothwell
[KF: fix devmem_is_allowed() on ARM]
Signed-off-by: Kefeng Wang
Reviewed-by: Tong Tiangen
Signed-off-by: Chen Jun
Signed-off-by: Zheng Zengkai
Signed-off-by: Yu Changchun
---
arch/arm/mm/mmap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index b8d912ac9e61..c64124fb34ea 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -179,7 +179,7 @@ int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
*/
int devmem_is_allowed(unsigned long pfn)
{
- if (iomem_is_exclusive(pfn << PAGE_SHIFT))
+ if (iomem_is_exclusive(PFN_PHYS(pfn)))
return 0;
if (!page_is_ram(pfn))
return 1;
--
2.25.1
