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Chuck Ebbert ecd744eec3 x86 - 32-bit ptrace emulation mishandles 6th arg ... [ jdike - Pushing Chuck's patch - see http://lkml.org/lkml/2005/9/16/261 for some history and a test program. UML is also broken without this patch - its processes get SIGBUS from the corrupt 6th argument to mmap being interpretted as a file offset ] When the 32-bit vDSO is used to make a system call, the %ebp register for the 6th syscall arg has to be loaded from the user stack (where it's pushed by the vDSO user code). The native i386 kernel always does this before stopping for syscall tracing, so %ebp can be seen and modified via ptrace to access the 6th syscall argument. The x86-64 kernel fails to do this, presenting the stack address to ptrace instead. This makes the %rbp value seen by 64-bit ptrace of a 32-bit process, and the %ebp value seen by a 32-bit caller of ptrace, both differ from the native i386 behavior. This patch fixes the problem by putting the word loaded from the user stack into %rbp before calling syscall_trace_enter, and reloading the 6th syscall argument from there afterwards (so ptrace can change it). This makes the behavior match that of i386 kernels. Original-Patch-By: Roland McGrath <roland@redhat.com> Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>		17 years ago
..
Makefile	x86_64: install unstripped copies of compat vdso on disk	18 years ago
audit.c	i386/x86_64: move headers to include/asm-x86	18 years ago
fpu32.c	x86_64: move ia32	18 years ago
ia32_aout.c	x86: initialize 64bit registers for a.out executables	18 years ago
ia32_binfmt.c	x86: Use linux/elfcore-compat.h	18 years ago
ia32_signal.c	x86_64: move ia32	18 years ago
ia32entry.S	x86 - 32-bit ptrace emulation mishandles 6th arg	17 years ago
ipc32.c	remove include/asm-*/ipc.h	18 years ago
mmap32.c	x86_64: move ia32	18 years ago
ptrace32.c	x86_64: ia32 ptrace THREAD_AREA fix	17 years ago
sys_ia32.c	x86_64: move ia32	18 years ago
syscall32.c	x86_64: move ia32	18 years ago
syscall32_syscall.S	x86_64: move ia32	18 years ago
tls32.c	x86_64: move ia32	18 years ago
vsyscall-sigreturn.S	x86_64: move ia32	18 years ago
vsyscall-syscall.S	x86_64: move ia32	18 years ago
vsyscall-sysenter.S	x86_64: move ia32	18 years ago
vsyscall.lds	x86_64: move ia32	18 years ago