Date: Tue, 19 Jan 2021 12:25:36 +0000 From: Edward Tomasz Napierala <trasz@freebsd.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org Subject: Re: git: 47f7345baba0 - main - linux: fix PTRACE_POKEDATA and PTRACE_POKETEXT. Message-ID: <YAbPwJ7b8R461mru@brick> In-Reply-To: <YAa/I0fVrYePRrK%2B@kib.kiev.ua> References: <202101191053.10JArcDa041994@gitrepo.freebsd.org> <YAa/I0fVrYePRrK%2B@kib.kiev.ua>
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On 0119T1314, Konstantin Belousov wrote: > On Tue, Jan 19, 2021 at 10:53:38AM +0000, Edward Tomasz Napierala wrote: > > The branch main has been updated by trasz: > > > > URL: https://cgit.FreeBSD.org/src/commit/?id=47f7345baba01121e29c22b43f68345399a32912 > > > > commit 47f7345baba01121e29c22b43f68345399a32912 > > Author: Edward Tomasz Napierala <trasz@FreeBSD.org> > > AuthorDate: 2021-01-15 16:57:24 +0000 > > Commit: Edward Tomasz Napierala <trasz@FreeBSD.org> > > CommitDate: 2021-01-19 10:30:55 +0000 > > > > linux: fix PTRACE_POKEDATA and PTRACE_POKETEXT. > > > > Sponsored by: The FreeBSD Foundation > > --- > > sys/amd64/linux/linux_ptrace.c | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/sys/amd64/linux/linux_ptrace.c b/sys/amd64/linux/linux_ptrace.c > > index a14155ed7e97..c1d05db5bc42 100644 > > --- a/sys/amd64/linux/linux_ptrace.c > > +++ b/sys/amd64/linux/linux_ptrace.c > > @@ -594,10 +594,15 @@ linux_ptrace(struct thread *td, struct linux_ptrace_args *uap) > > error = linux_ptrace_peekuser(td, pid, addr, (void *)uap->data); > > break; > > case LINUX_PTRACE_POKETEXT: > > - error = kern_ptrace(td, PT_WRITE_I, pid, addr, uap->data); > > - break; > This is wrong. You should access text AS if linux request was for text. Do we actually want to maintain that distinction? Looking at sys/kern/sys_process.c, they are synonyms. > > case LINUX_PTRACE_POKEDATA: > > error = kern_ptrace(td, PT_WRITE_D, pid, addr, uap->data); > > + if (error != 0) > > + return (error); > > + /* > > + * Linux expects this syscall to write 64 bits, not 32. > > + */ > > + error = kern_ptrace(td, PT_WRITE_D, pid, > > + (void *)(uap->addr + 4), uap->data >> 32); > > break; > You should use PT_IO there instead of doing two accesses (to the wrong AS). Hm, you're right. The only problem I can see is that PT_IO fetches struct ptrace_io_desc from userspace, which makes wrapping somewhat hard. How about introducing PT_READ64 and PT_WRITE64 request types and using them instead? Thanks!
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