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maccess: unify the probe kernel arch hooks

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Currently architectures have to override every routine that probes
kernel memory, which includes a pure read and strcpy, both in strict
and not strict variants.  Just provide a single arch hooks instead to
make sure all architectures cover all the cases.

[akpm@linux-foundation.org: fix !CONFIG_X86_64 build]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-11-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Christoph Hellwig
2020-06-08 21:34:27 -07:00
committed by Linus Torvalds
parent cd0309058f
commit eab0c6089b
5 changed files with 61 additions and 50 deletions
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33
arch/x86/mm/maccess.c
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@@ -9,35 +9,26 @@ static __always_inline u64 canonical_address(u64 vaddr, u8 vaddr_bits)
return ((s64)vaddr << (64 - vaddr_bits)) >> (64 - vaddr_bits);
}
static __always_inline bool invalid_probe_range(u64 vaddr)
bool probe_kernel_read_allowed(const void *unsafe_src, size_t size, bool strict)
{
unsigned long vaddr = (unsigned long)unsafe_src;
if (!strict)
return true;
/*
* Range covering the highest possible canonical userspace address
* as well as non-canonical address range. For the canonical range
* we also need to include the userspace guard page.
*/
return vaddr < TASK_SIZE_MAX + PAGE_SIZE ||
canonical_address(vaddr, boot_cpu_data.x86_virt_bits) != vaddr;
return vaddr >= TASK_SIZE_MAX + PAGE_SIZE &&
canonical_address(vaddr, boot_cpu_data.x86_virt_bits) == vaddr;
}
#else
static __always_inline bool invalid_probe_range(u64 vaddr)
bool probe_kernel_read_allowed(const void *unsafe_src, size_t size, bool strict)
{
return vaddr < TASK_SIZE_MAX;
if (!strict)
return true;
return (unsigned long)unsafe_src >= TASK_SIZE_MAX;
}
#endif
long probe_kernel_read_strict(void *dst, const void *src, size_t size)
{
if (unlikely(invalid_probe_range((unsigned long)src)))
return -EFAULT;
return __probe_kernel_read(dst, src, size);
}
long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count)
{
if (unlikely(invalid_probe_range((unsigned long)unsafe_addr)))
return -EFAULT;
return __strncpy_from_unsafe(dst, unsafe_addr, count);
}