qemu/linux-user
Helge Deller 0102c92a1c linux-user: Fix qemu brk() to not zero bytes on current page
The qemu brk() implementation is too aggressive and cleans remaining bytes
on the current page above the last brk address.

But some existing applications are buggy and read/write bytes above their
current heap address. On a phyiscal machine this does not trigger a
runtime error as long as the access happens on the same page. Additionally
the Linux kernel allocates only full pages and does no zeroing on already
allocated pages, even if the brk address is lowered.

Fix qemu to behave the same way as the kernel does. Do not touch already
allocated pages, and - when running with different page sizes of guest and
host - zero out only those memory areas where the host page size is bigger
than the guest page size.

Signed-off-by: Helge Deller <deller@gmx.de>
Tested-by: "Markus F.X.J. Oberhumer" <markus@oberhumer.com>
Fixes: 86f04735ac ("linux-user: Fix brk() to release pages")
Cc: qemu-stable@nongnu.org
Buglink: https://github.com/upx/upx/issues/683
(cherry picked from commit 15ad98536a)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2023-07-31 08:52:38 +03:00
..
aarch64 linux-user: move target_flat.h to target subdirs 2023-02-03 22:55:12 +01:00
alpha linux-user: Add translation for argument of msync() 2023-03-10 20:45:47 +01:00
arm include/exec: Change reserved_va semantics to last byte 2023-03-28 15:23:10 -07:00
cris linux-user: Provide MADV_* definitions 2022-09-27 09:30:09 +02:00
generic linux-user: Add translation for argument of msync() 2023-03-10 20:45:47 +01:00
hexagon linux-user/hexagon: fix signal context save & restore 2023-01-05 09:19:02 -08:00
hppa linux-user: Add translation for argument of msync() 2023-03-10 20:45:47 +01:00
i386 linux-user: fix bug about incorrect base addresss of gdt on i386 and x86_64 2023-03-10 20:50:11 +01:00
include linux-user: Implment host/ppc/host-signal.h 2023-01-23 14:39:48 -10:00
loongarch64 linux-user: Provide MADV_* definitions 2022-09-27 09:30:09 +02:00
m68k linux-user: move target_flat.h to target subdirs 2023-02-03 22:55:12 +01:00
microblaze linux-user/microblaze: Handle privileged exception 2023-02-21 08:44:13 -10:00
mips linux-user: Fix mips fp64 executables loading 2023-05-18 14:44:13 +03:00
mips64 linux-user: Provide MADV_* definitions 2022-09-27 09:30:09 +02:00
nios2 linux-user: Provide MADV_* definitions 2022-09-27 09:30:09 +02:00
openrisc linux-user: Provide MADV_* definitions 2022-09-27 09:30:09 +02:00
ppc linux-user: Provide MADV_* definitions 2022-09-27 09:30:09 +02:00
riscv linux-user: Provide MADV_* definitions 2022-09-27 09:30:09 +02:00
s390x linux-user/s390x: Fix single-stepping SVC 2023-06-07 12:36:29 +03:00
sh4 linux-user: move target_flat.h to target subdirs 2023-02-03 22:55:12 +01:00
sparc linux-user/sparc: Handle tag overflow traps 2023-03-10 20:45:47 +01:00
x86_64 linux-user: Provide MADV_* definitions 2022-09-27 09:30:09 +02:00
xtensa linux-user: Provide MADV_* definitions 2022-09-27 09:30:09 +02:00
cpu_loop-common.h linux-user: Add guest memory layout to exception dump 2022-10-25 09:20:40 +02:00
elfload.c linux-user/arm: Do not allocate a commpage at all for M-profile CPUs 2023-07-31 08:52:38 +03:00
errnos.c.inc linux-user: Simplify host <-> target errno conversion using macros 2021-07-12 21:53:35 +02:00
exit.c *: Add missing includes of qemu/plugin.h 2023-03-22 15:06:57 +00:00
fd-trans.c linux-user: handle netlink flag NLA_F_NESTED 2023-03-10 20:45:47 +01:00
fd-trans.h linux-user: fix timerfd read endianness conversion 2023-03-10 20:42:00 +01:00
flat.h linux-user/: fix some comment spelling errors 2020-09-17 20:39:22 +02:00
flatload.c linux-user: Pass last not end to probe_guest_base 2023-03-28 15:23:10 -07:00
ioctls.h linux-user: remove conditionals for many fs.h ioctls 2022-10-21 17:46:19 +02:00
linux_loop.h linux-user: implement more loop ioctls 2021-11-29 14:54:17 +01:00
linuxload.c linux-user: Clean up arg_start/arg_end confusion 2022-05-23 08:15:19 +02:00
loader.h linux-user: Split loader-related prototypes into loader.h 2021-09-13 20:35:44 +02:00
main.c include/exec: Change reserved_va semantics to last byte 2023-03-28 15:23:10 -07:00
meson.build accel/tcg: Add debuginfo support 2023-01-16 10:14:12 -10:00
mmap.c linux-user: Avoid mmap of the last byte of the reserved_va 2023-07-01 13:57:27 +03:00
qemu.h linux-user: Honor PT_GNU_STACK 2022-09-06 08:04:25 +01:00
semihost.c semihosting: Remove qemu_semihosting_console_outs 2022-06-28 04:41:20 +05:30
signal-common.h linux-user: Add missing signals in strace output 2022-09-27 09:29:33 +02:00
signal.c gdbstub: move chunks of user code into own files 2023-03-07 20:44:04 +00:00
socket.h Supply missing header guards 2019-06-12 13:20:21 +02:00
strace.c linux-user: Emulate CLONE_PIDFD flag in clone() 2023-03-10 20:45:47 +01:00
strace.h linux-user: Have do_syscall() use CPUArchState* instead of void* 2022-05-23 22:47:19 +02:00
strace.list linux-user: Add translation for argument of msync() 2023-03-10 20:45:47 +01:00
syscall.c linux-user: Fix qemu brk() to not zero bytes on current page 2023-07-31 08:52:38 +03:00
syscall_defs.h linux-user/sparc: Don't use 16-bit UIDs on SPARC V9 2023-03-30 15:03:23 +02:00
syscall_types.h linux-user: implement more loop ioctls 2021-11-29 14:54:17 +01:00
thunk.c linux-user: Move thunk.c from top-level 2021-12-20 10:12:29 -08:00
trace-events linux-user: Rename user_force_sig tracepoint to match function name 2022-01-18 12:41:42 +01:00
trace.h trace: switch position of headers to what Meson requires 2020-08-21 06:18:24 -04:00
uaccess.c linux-user: Split linux-user internals out of qemu.h 2021-09-13 20:35:45 +02:00
uname.c linux-user: Remove pointless CPU{ARCH}State casts 2022-05-23 22:47:20 +02:00
uname.h linux-user: Have do_syscall() use CPUArchState* instead of void* 2022-05-23 22:47:19 +02:00
user-internals.h linux-user: Pass last not end to probe_guest_base 2023-03-28 15:23:10 -07:00
user-mmap.h linux-user: Add partial support for MADV_DONTNEED 2022-06-24 10:00:00 +02:00
vm86.c linux-user: Split linux-user internals out of qemu.h 2021-09-13 20:35:45 +02:00