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| author | Oleg Nesterov <oleg@redhat.com> | 2014-04-28 20:15:43 +0200 |
|---|---|---|
| committer | Oleg Nesterov <oleg@redhat.com> | 2014-04-30 19:10:43 +0200 |
| commit | 13f59c5e45be59665c11ddde19799b6295543b7d (patch) | |
| tree | 86b9999733f0826f2bad3e4d2285d9585f3a9f67 /kernel/events | |
| parent | 927d687480ab7e43d73a003bab58803fc67717d9 (diff) | |
| download | op-kernel-dev-13f59c5e45be59665c11ddde19799b6295543b7d.zip op-kernel-dev-13f59c5e45be59665c11ddde19799b6295543b7d.tar.gz | |
uprobes: Refuse to insert a probe into MAP_SHARED vma
valid_vma() rejects the VM_SHARED vmas, but this still allows to insert
a probe into the MAP_SHARED but not VM_MAYWRITE vma.
Currently this is fine, such a mapping doesn't really differ from the
private read-only mmap except mprotect(PROT_WRITE) won't work. However,
get_user_pages(FOLL_WRITE | FOLL_FORCE) doesn't allow to COW in this
case, and it would be safer to follow the same conventions as mm even
if currently this happens to work.
After the recent cda540ace6a1 "mm: get_user_pages(write,force) refuse
to COW in shared areas" only uprobes can insert an anon page into the
shared file-backed area, lets stop this and change valid_vma() to check
VM_MAYSHARE instead.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Diffstat (limited to 'kernel/events')
| -rw-r--r-- | kernel/events/uprobes.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index d1edc5e..7716c40 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -127,7 +127,7 @@ struct xol_area { */ static bool valid_vma(struct vm_area_struct *vma, bool is_register) { - vm_flags_t flags = VM_HUGETLB | VM_MAYEXEC | VM_SHARED; + vm_flags_t flags = VM_HUGETLB | VM_MAYEXEC | VM_MAYSHARE; if (is_register) flags |= VM_WRITE; |
