diff options
| author | Arve Hjønnevåg <arve@android.com> | 2016-08-02 15:40:39 -0700 |
|---|---|---|
| committer | Pat Tjin <pattjin@google.com> | 2016-08-23 03:27:06 +0000 |
| commit | 5e2a2bc89956ae1c739854403408059144b23c28 (patch) | |
| tree | 9b6f8eb64cc838c1c2762b583e133e1347a2d322 | |
| parent | 9930e89e5cc32fee3e551e169a670e6cc8125f6c (diff) | |
ANDROID: binder: Add strong ref checks
Prevent using a binder_ref with only weak references where a strong
reference is required.
BUG: 30445380
Change-Id: I66c15b066808f28bd27bfe50fd0e03ff45a09fca
Signed-off-by: Arve Hjønnevåg <arve@android.com>
| -rw-r--r-- | drivers/staging/android/binder.c | 26 |
1 files changed, 17 insertions, 9 deletions
diff --git a/drivers/staging/android/binder.c b/drivers/staging/android/binder.c index b100985f2ecb..67bf35f94623 100644 --- a/drivers/staging/android/binder.c +++ b/drivers/staging/android/binder.c @@ -1058,7 +1058,7 @@ static int binder_dec_node(struct binder_node *node, int strong, int internal) static struct binder_ref *binder_get_ref(struct binder_proc *proc, - uint32_t desc) + uint32_t desc, bool need_strong_ref) { struct rb_node *n = proc->refs_by_desc.rb_node; struct binder_ref *ref; @@ -1066,12 +1066,16 @@ static struct binder_ref *binder_get_ref(struct binder_proc *proc, while (n) { ref = rb_entry(n, struct binder_ref, rb_node_desc); - if (desc < ref->desc) + if (desc < ref->desc) { n = n->rb_left; - else if (desc > ref->desc) + } else if (desc > ref->desc) { n = n->rb_right; - else + } else if (need_strong_ref && !ref->strong) { + binder_user_error("tried to use weak ref as strong ref\n"); + return NULL; + } else { return ref; + } } return NULL; } @@ -1338,7 +1342,8 @@ static void binder_transaction_buffer_release(struct binder_proc *proc, } break; case BINDER_TYPE_HANDLE: case BINDER_TYPE_WEAK_HANDLE: { - struct binder_ref *ref = binder_get_ref(proc, fp->handle); + struct binder_ref *ref = binder_get_ref(proc, fp->handle, + fp->type == BINDER_TYPE_HANDLE); if (ref == NULL) { pr_err("transaction release %d bad handle %d\n", debug_id, fp->handle); @@ -1431,7 +1436,7 @@ static void binder_transaction(struct binder_proc *proc, } else { if (tr->target.handle) { struct binder_ref *ref; - ref = binder_get_ref(proc, tr->target.handle); + ref = binder_get_ref(proc, tr->target.handle, true); if (ref == NULL) { binder_user_error("%d:%d got transaction to invalid handle\n", proc->pid, thread->pid); @@ -1634,7 +1639,8 @@ static void binder_transaction(struct binder_proc *proc, } break; case BINDER_TYPE_HANDLE: case BINDER_TYPE_WEAK_HANDLE: { - struct binder_ref *ref = binder_get_ref(proc, fp->handle); + struct binder_ref *ref = binder_get_ref(proc, fp->handle, + fp->type == BINDER_TYPE_HANDLE); if (ref == NULL) { binder_user_error("%d:%d got transaction with invalid handle, %d\n", proc->pid, @@ -1845,7 +1851,9 @@ static int binder_thread_write(struct binder_proc *proc, ref->desc); } } else - ref = binder_get_ref(proc, target); + ref = binder_get_ref(proc, target, + cmd == BC_ACQUIRE || + cmd == BC_RELEASE); if (ref == NULL) { binder_user_error("%d:%d refcount change on invalid ref %d\n", proc->pid, thread->pid, target); @@ -2047,7 +2055,7 @@ static int binder_thread_write(struct binder_proc *proc, if (get_user_preempt_disabled(cookie, (binder_uintptr_t __user *)ptr)) return -EFAULT; ptr += sizeof(binder_uintptr_t); - ref = binder_get_ref(proc, target); + ref = binder_get_ref(proc, target, false); if (ref == NULL) { binder_user_error("%d:%d %s invalid ref %d\n", proc->pid, thread->pid, |