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author | Lennert Buytenhek <buytenh@wantstofly.org> | 2006-09-16 10:50:22 +0100 |
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committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2006-09-25 10:25:26 +0100 |
commit | 51635ad282ead58b9d164f07e1fb62a9456b427c (patch) | |
tree | a7d9fb162d09aaf02da3dee89520b10c07d92c8b /arch/arm/mm | |
parent | bf11d26cb96fe8221ef056eedab692e91634cc65 (diff) | |
download | kernel_samsung_smdk4412-51635ad282ead58b9d164f07e1fb62a9456b427c.zip kernel_samsung_smdk4412-51635ad282ead58b9d164f07e1fb62a9456b427c.tar.gz kernel_samsung_smdk4412-51635ad282ead58b9d164f07e1fb62a9456b427c.tar.bz2 |
[ARM] 3813/1: prevent >= 4G /dev/mem mmap()
Prevent userland from mapping in physical address regions >= 4G by
checking for that in valid_mmap_phys_addr_range().
Unfortunately, we cannot override valid_mmap_phys_addr_range() without
also overriding valid_phys_addr_range(), so copy drivers/char/mem.c's
version of valid_phys_addr_range() over to arch/arm/mm/mmap.c as well.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mm')
-rw-r--r-- | arch/arm/mm/mmap.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index 29e5480..b0b5f46 100644 --- a/arch/arm/mm/mmap.c +++ b/arch/arm/mm/mmap.c @@ -114,3 +114,25 @@ full_search: } } + +/* + * You really shouldn't be using read() or write() on /dev/mem. This + * might go away in the future. + */ +int valid_phys_addr_range(unsigned long addr, size_t size) +{ + if (addr + size > __pa(high_memory)) + return 0; + + return 1; +} + +/* + * We don't use supersection mappings for mmap() on /dev/mem, which + * means that we can't map the memory area above the 4G barrier into + * userspace. + */ +int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) +{ + return !(pfn + (size >> PAGE_SHIFT) > 0x00100000); +} |