| Message ID | 88d5255400fc6536d6a6895dd2a3aef0f0ecc899.1553093421.git.andreyknvl@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: untag user pointers passed to the kernel | expand |
On Wed, Mar 20, 2019 at 03:51:26PM +0100, Andrey Konovalov wrote: > This patch is a part of a series that extends arm64 kernel ABI to allow to > pass tagged user pointers (with the top byte set to something else other > than 0x00) as syscall arguments. > > find_active_uprobe() uses user pointers (obtained via > instruction_pointer(regs)) for vma lookups, which can only by done with > untagged pointers. > > Untag user pointers in this function. > > Signed-off-by: Andrey Konovalov <andreyknvl@google.com> > --- > kernel/events/uprobes.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c > index c5cde87329c7..d3a2716a813a 100644 > --- a/kernel/events/uprobes.c > +++ b/kernel/events/uprobes.c > @@ -1992,6 +1992,8 @@ static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp) > struct uprobe *uprobe = NULL; > struct vm_area_struct *vma; > > + bp_vaddr = untagged_addr(bp_vaddr); > + > down_read(&mm->mmap_sem); > vma = find_vma(mm, bp_vaddr); > if (vma && vma->vm_start <= bp_vaddr) { Similarly here, that's a breakpoint address, hence instruction pointer (PC) which is untagged.
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index c5cde87329c7..d3a2716a813a 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1992,6 +1992,8 @@ static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp) struct uprobe *uprobe = NULL; struct vm_area_struct *vma; + bp_vaddr = untagged_addr(bp_vaddr); + down_read(&mm->mmap_sem); vma = find_vma(mm, bp_vaddr); if (vma && vma->vm_start <= bp_vaddr) {
This patch is a part of a series that extends arm64 kernel ABI to allow to pass tagged user pointers (with the top byte set to something else other than 0x00) as syscall arguments. find_active_uprobe() uses user pointers (obtained via instruction_pointer(regs)) for vma lookups, which can only by done with untagged pointers. Untag user pointers in this function. Signed-off-by: Andrey Konovalov <andreyknvl@google.com> --- kernel/events/uprobes.c | 2 ++ 1 file changed, 2 insertions(+)