| 2018-07-03 22:35:00 |
Kan Li |
description |
When read() function takes an mmap'ed address as output buffer, it returns EFAULT. The expected behavior is it should just work.
The following code works for qemu-system-arm, but not for qemu-arm-static.
Steps to reproduce (please substitute /path/to/qemu-arm-static with the path of the binary, and /tmp/a.cpp with the example source code attached):
# First register binfmt_misc
[hidden]$ docker run --rm --privileged multiarch/qemu-user-static:register --reset
# Compile the code and run
[hidden]$ docker run --rm -it -v /tmp/a.cpp:/tmp/a.cpp -v /path/to/qemu-arm-static:/usr/bin/qemu-arm-static arm32v7/ubuntu:18.04 bash -c '{ apt update -y && apt install -y g++; } >& /dev/null && g++ -std=c++14 /tmp/a.cpp -o /tmp/a.out && echo hehe > /tmp/haha.txt && /tmp/a.out'
ofd=3
ftruncate=0
mmap=0xff3f5000
fd=4
0xff3f5023 -1 14
The expected result in qemu-system-arm as well as natively on x86_64 host:
hidden$ ./a.out
ofd=3
ftruncate=0
mmap=0xb6fb7000
fd=4
0xb6fb7023 5 0 |
When read() function takes an mmap'ed address as output buffer, it returns EFAULT. The expected behavior is it should just work.
The following code works for qemu-system-arm, but not for qemu-arm-static.
QEMU version affected: latest release 2.12.0.
Steps to reproduce (please substitute /path/to/qemu-arm-static with the path of the binary, and /tmp/a.cpp with the example source code attached):
# First register binfmt_misc
[hidden]$ docker run --rm --privileged multiarch/qemu-user-static:register --reset
# Compile the code and run
[hidden]$ docker run --rm -it -v /tmp/a.cpp:/tmp/a.cpp -v /path/to/qemu-arm-static:/usr/bin/qemu-arm-static arm32v7/ubuntu:18.04 bash -c '{ apt update -y && apt install -y g++; } >& /dev/null && g++ -std=c++14 /tmp/a.cpp -o /tmp/a.out && echo hehe > /tmp/haha.txt && /tmp/a.out'
ofd=3
ftruncate=0
mmap=0xff3f5000
fd=4
0xff3f5023 -1 14
The expected result in qemu-system-arm as well as natively on x86_64 host:
hidden$ ./a.out
ofd=3
ftruncate=0
mmap=0xb6fb7000
fd=4
0xb6fb7023 5 0 |
|
