mirror of
https://github.com/checkpoint-restore/criu.git
synced 2026-07-30 05:21:57 +00:00
8f74187af1
The register R12 has a special meaning when syscalls are hooked with ptrace() in ARM that results in a dumpee context corruption on an injected blob unmap. Note that this patch doesn't solve the problem entirely since the compiler may corrupt the register before issuing a call to the routine sys_munmap(); however we assume that a sufficiently decent compiler doesn't. Signed-off-by: Alexander Kartashov <alekskartashov@parallels.com> Tested-by: Andrew Vagin <avagin@parallels.com> Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
34 lines
731 B
ArmAsm
34 lines
731 B
ArmAsm
#include "asm/linkage.h"
|
|
|
|
@ We use the register R8 unlike libc that uses R12.
|
|
@ This avoids corruption of the register by the stub
|
|
@ for the syscall sys_munmap() when syscalls are hooked
|
|
@ by ptrace(). However we have to make sure that
|
|
@ the compiler doesn't use the register on the route
|
|
@ between parasite_service() and sys_munmap().
|
|
|
|
syscall_common:
|
|
ldr %r7, [%r7]
|
|
add %r8, %sp, #24
|
|
ldm %r8, {%r4, %r5, %r6}
|
|
svc 0x00000000
|
|
pop {%r4, %r5, %r6, %r7, %r8, %pc}
|
|
|
|
|
|
.macro syscall name, nr
|
|
.nr_\name :
|
|
.long \nr
|
|
|
|
ENTRY(\name)
|
|
push {%r4, %r5, %r6, %r7, %r8, %lr}
|
|
adr %r7, .nr_\name
|
|
b syscall_common
|
|
END(\name)
|
|
.endm
|
|
|
|
|
|
ENTRY(__cr_restore_rt)
|
|
adr %r7, .nr_sys_rt_sigreturn
|
|
ldr %r7, [%r7]
|
|
svc #0
|
|
END(__cr_restore_rt)
|