Messages in this thread | | | Date | Mon, 5 Mar 2018 16:07:10 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] mm: relax ptrace mode in process_vm_readv(2) |
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On Sat, 3 Mar 2018 23:11:16 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote:
> It is more natural to check for read-from-memory permissions in case of > process_vm_readv() as PTRACE_MODE_ATTACH is equivalent to write > permissions. > > ... > > --- a/mm/process_vm_access.c > +++ b/mm/process_vm_access.c > @@ -204,7 +204,7 @@ static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter, > goto free_proc_pages; > } > > - mm = mm_access(task, PTRACE_MODE_ATTACH_REALCREDS); > + mm = mm_access(task, vm_write ? PTRACE_MODE_ATTACH_REALCREDS : PTRACE_MODE_READ_REALCREDS); > if (!mm || IS_ERR(mm)) { > rc = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH; > /*
But what is the risk of breaking existing userspace?
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