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Groups > linux.kernel > #1296179
| From | Mickaël Salaün <mic@digikod.net> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v1 1/4] um: Fix ptrace GETREGS/SETREGS bugs |
| Date | 2015-12-21 21:00 +0100 |
| Message-ID | <qIeMG-2kK-3@gated-at.bofh.it> (permalink) |
| References | (2 earlier) <qHWwp-7K0-1@gated-at.bofh.it> <qI4tX-4fy-3@gated-at.bofh.it> <qI4DD-4y3-5@gated-at.bofh.it> <qI4WZ-4EK-9@gated-at.bofh.it> <qI5Jo-5ac-19@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
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On 21/12/2015 11:13, Richard Weinberger wrote: > Am 21.12.2015 um 10:23 schrieb Mickaël Salaün: >>>>> Doesn't this break the support for changing syscall numbers using PTRACE_SETREGS? >>>> >>>> The logic is unchanged except updating the UPT_SYSCALL_NR before syscall_trace_enter(). I did my last tests with the x86_32 subarchitecture and all tests (from selftest/seccomp), including PTRACE_SETREGS for syscall numbers tests, passed. However, 2 of this tests still fail for x86_64 (only). >>> >>> No, the logic is different. >>> syscall_trace_enter(regs) enters the ptrace() path and here registers can be changed. >>> Hence "syscall = UPT_SYSCALL_NR(r);" will see the old syscall number. >>> UPT_SYSCALL_NR() returns the syscall number before the ptrace() path... >> >> The thing is, PTRACE_SETREGS give access to *orig_ax* in the user_regs_struct from arch/x86/include/asm/user_*.h and selftest/seccomp only update this (virtual) register, not the EAX/RAX. Am I missing something? > > Sorry, meant orig... > > Please see the attached program. It proves that your patch is breaking stuff. > The test is extracted from UML's selftests. OK, I found the origin of this misunderstanding. On x86_32, PTRACE_SETREGS set regs->syscall when updating orig_eax, which is not the case on x86_64, hence the difference of behavior. I fixed this bug in the v2 series. The ptsc test and all the seccomp tests pass for 32 and 64 bits! Where can we find the UML selftests? Thanks, Mickaël
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[PATCH v1 0/4] um: Add seccomp support Mickaël Salaün <mic@digikod.net> - 2015-12-21 01:10 +0100
[PATCH v1 4/4] um: Add seccomp support Mickaël Salaün <mic@digikod.net> - 2015-12-21 01:20 +0100
[PATCH v1 1/4] um: Fix ptrace GETREGS/SETREGS bugs Mickaël Salaün <mic@digikod.net> - 2015-12-21 01:20 +0100
Re: [PATCH v1 1/4] um: Fix ptrace GETREGS/SETREGS bugs Richard Weinberger <richard@nod.at> - 2015-12-21 01:30 +0100
Re: [PATCH v1 1/4] um: Fix ptrace GETREGS/SETREGS bugs Richard Weinberger <richard@nod.at> - 2015-12-21 10:00 +0100
Re: [PATCH v1 1/4] um: Fix ptrace GETREGS/SETREGS bugs Richard Weinberger <richard@nod.at> - 2015-12-21 10:10 +0100
Re: [PATCH v1 1/4] um: Fix ptrace GETREGS/SETREGS bugs Mickaël Salaün <mic@digikod.net> - 2015-12-21 10:30 +0100
Re: [PATCH v1 1/4] um: Fix ptrace GETREGS/SETREGS bugs Richard Weinberger <richard@nod.at> - 2015-12-21 11:20 +0100
Re: [PATCH v1 1/4] um: Fix ptrace GETREGS/SETREGS bugs Mickaël Salaün <mic@digikod.net> - 2015-12-21 21:00 +0100
Re: [PATCH v1 1/4] um: Fix ptrace GETREGS/SETREGS bugs Mickaël Salaün <mic@digikod.net> - 2015-12-21 10:20 +0100
[PATCH v1 2/4] selftests/seccomp: Remove the need for HAVE_ARCH_TRACEHOOK Mickaël Salaün <mic@digikod.net> - 2015-12-21 01:30 +0100
[PATCH v1 3/4] um: Add full asm/syscall.h support Mickaël Salaün <mic@digikod.net> - 2015-12-21 01:30 +0100
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