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[Qemu-devel] [Bug 1783362] Re: qemu-user-aarch64: mmap returns success (
From: |
umarcor |
Subject: |
[Qemu-devel] [Bug 1783362] Re: qemu-user-aarch64: mmap returns success (NULL, 0) instead of failure (MAP_FAILED, -1) with len==0 |
Date: |
Wed, 25 Jul 2018 15:23:50 -0000 |
I did some research and found that this bug is present since 2003:
- 2003/05/13:
https://github.com/qemu/qemu/commit/54936004fddc52c321cb3f9a9a51140e782bed5d#diff-2bf4728e0473404c39c97190bd02b2f8
-
https://github.com/qemu/qemu/blob/54936004fddc52c321cb3f9a9a51140e782bed5d/linux-user/mmap.c#L182-L183
- 2008/06/02:
https://github.com/qemu/qemu/commit/c8a706fe6242a553960ccc3071a4e75ceba6f3d2#diff-2bf4728e0473404c39c97190bd02b2f8
-
https://github.com/qemu/qemu/blob/c8a706fe6242a553960ccc3071a4e75ceba6f3d2/linux-user/mmap.c#L284-L285
-
https://github.com/qemu/qemu/blob/c8a706fe6242a553960ccc3071a4e75ceba6f3d2/linux-user/mmap.c#L400-L410
It is present in versions 2.11.2, 2.12.0 and master:
- https://github.com/qemu/qemu/blob/v2.11.2/linux-user/mmap.c#L401-L402
- https://github.com/qemu/qemu/blob/v2.12.0/linux-user/mmap.c#L401-L402
- https://github.com/qemu/qemu/blob/master/linux-user/mmap.c#L400-L401
I think that a possible fix is:
@@ -397,8 +397,10 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int
prot,
}
len = TARGET_PAGE_ALIGN(len);
- if (len == 0)
- goto the_end;
+ if (len == 0) {
+ errno = EINVAL;
+ goto fail;
+ }
real_start = start & qemu_host_page_mask;
host_offset = offset & qemu_host_page_mask;
--
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https://bugs.launchpad.net/bugs/1783362
Title:
qemu-user-aarch64: mmap returns success (NULL, 0) instead of failure
(MAP_FAILED, -1) with len==0
Status in QEMU:
New
Status in qemu package in Ubuntu:
New
Bug description:
As shown in https://github.com/beehive-
lab/mambo/issues/19#issuecomment-407420602, with len==0 mmap returns
success (NULL, 0) instead of failure (MAP_FAILED, -1) in a x86_64 host
executing a ELF 64-bit LSB executable, ARM aarch64 binary.
Steps to reproduce the bug:
- (cross-)compile the attached source file:
$ aarch64-linux-gnu-gcc -static -std=gnu99 -lpthread test/mmap_qemu.c
-o mmap_qemu
- Execute in a x86_64 host with qemu-user and qemu-user-binfmt:
$ ./mmap_qemu
alloc: 0
MAP_FAILED: -1
errno: 0
mmap_qemu: test/mmap_qemu.c:15: main: Assertion `alloc == MAP_FAILED' failed.
qemu: uncaught target signal 6 (Aborted) - core dumped
Aborted (core dumped)
- Execute in a ARM host without any additional dependecy:
$ ./mmap_qemu
alloc: -1
MAP_FAILED: -1
errno: 22
The bug is present in Fedora:
$ qemu-aarch64 --version
qemu-aarch64 version 2.11.2(qemu-2.11.2-1.fc28)
Copyright (c) 2003-2017 Fabrice Bellard and the QEMU Project developers
$ uname -r
4.17.7-200.fc28.x86_64
And also in Ubuntu:
$ qemu-aarch64 --version
qemu-aarch64 version 2.12.0 (Debian 1:2.12+dfsg-3ubuntu3)
Copyright (c) 2003-2017 Fabrice Bellard and the QEMU Project developers
$ uname -r
4.15.0-23-generic
Possibly related to:
- https://lists.freebsd.org/pipermail/freebsd-hackers/2009-July/029109.html
- https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=203852
To manage notifications about this bug go to:
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- [Qemu-devel] [Bug 1783362] [NEW] qemu-user-aarch64: mmap returns success (NULL, 0) instead of failure (MAP_FAILED, -1) with len==0, umarcor, 2018/07/24
- [Qemu-devel] [Bug 1783362] Re: qemu-user-aarch64: mmap returns success (NULL, 0) instead of failure (MAP_FAILED, -1) with len==0,
umarcor <=
- [Qemu-devel] [Bug 1783362] Re: qemu-user: mmap should return failure (MAP_FAILED, -1) instead of success (NULL, 0) when len==0, umarcor, 2018/07/25
- [Qemu-devel] [Bug 1783362] Re: qemu-user: mmap should return failure (MAP_FAILED, -1) instead of success (NULL, 0) when len==0, umarcor, 2018/07/25
- [Qemu-devel] [Bug 1783362] Re: qemu-user: mmap should return failure (MAP_FAILED, -1) instead of success (NULL, 0) when len==0, umarcor, 2018/07/29
- [Qemu-devel] [Bug 1783362] Re: qemu-user: mmap should return failure (MAP_FAILED, -1) instead of success (NULL, 0) when len==0, umarcor, 2018/07/31