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authorOleg Nesterov <oleg@redhat.com>2014-04-28 20:15:43 +0200
committerOleg Nesterov <oleg@redhat.com>2014-04-30 19:10:43 +0200
commit13f59c5e45be59665c11ddde19799b6295543b7d (patch)
tree86b9999733f0826f2bad3e4d2285d9585f3a9f67 /kernel/events
parent927d687480ab7e43d73a003bab58803fc67717d9 (diff)
downloadop-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.c2
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;
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