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[PATCH] linux-user/mmap: Avoid asserts for out of range mremap calls
From: |
Richard Purdie |
Subject: |
[PATCH] linux-user/mmap: Avoid asserts for out of range mremap calls |
Date: |
Fri, 08 Jan 2021 17:42:12 +0000 |
User-agent: |
Evolution 3.38.1-1 |
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
Index: qemu-5.2.0/linux-user/mmap.c
===================================================================
--- qemu-5.2.0.orig/linux-user/mmap.c
+++ qemu-5.2.0/linux-user/mmap.c
@@ -727,7 +727,9 @@ abi_long target_mremap(abi_ulong old_add
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;
}
- [PATCH] linux-user/mmap: Avoid asserts for out of range mremap calls,
Richard Purdie <=