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linux-user/mmap: Avoid asserts for out of range mremap calls 

If mremap() is called without the MREMAP_MAYMOVE flag with a start address
just before the end of memory (reserved_va) where new_size would exceed
it (and GUEST_ADDR_MAX), the assert(end - 1 <= GUEST_ADDR_MAX) in 
page_set_flags() would trigger.

Add an extra guard to the guest_range_valid() checks to prevent this and
avoid asserting binaries when reserved_va is set.

This meant a bug I was seeing locally now gives the same behaviour 
regardless of whether reserved_va is set or not.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org
Reviewed-by: Laurent Vivier <laurent@vivier.eu>

Message-Id: <70c46e7b999bafbb01d54bfafd44b420d0b782e9.camel@linuxfoundation.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
This commit is contained in:
Richard Purdie 2021-01-08 17:42:12 +00:00 committed by Laurent Vivier
parent 22d113b52f
commit ccc5ccc17f
1 changed files with 3 additions and 1 deletions
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4
linux-user/mmap.c
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@ -724,7 +724,9 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
if (!guest_range_valid(old_addr, old_size) ||
((flags & MREMAP_FIXED) &&
!guest_range_valid(new_addr, new_size))) {
!guest_range_valid(new_addr, new_size)) ||
((flags & MREMAP_MAYMOVE) == 0 &&
!guest_range_valid(old_addr, new_size))) {
errno = ENOMEM;
return -1;
}