From 212265e5ad726ed7fd2ec7d61d36d9e0b0d3e655 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= <arve@android.com>
Date: Tue, 9 Feb 2016 21:05:32 -0800
Subject: [PATCH] android: binder: More offset validation
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Make sure offsets don't point to overlapping flat_binder_object
structs.
Cc: Colin Cross <ccross@android.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Cc: Rom Lemarchand <romlem@google.com>
Cc: Serban Constantinescu <serban.constantinescu@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/android/binder.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index a39e85f9efa98..1db376184955d 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -1321,6 +1321,7 @@ static void binder_transaction(struct binder_proc *proc,
struct binder_transaction *t;
struct binder_work *tcomplete;
binder_size_t *offp, *off_end;
+ binder_size_t off_min;
struct binder_proc *target_proc;
struct binder_thread *target_thread = NULL;
struct binder_node *target_node = NULL;
@@ -1522,18 +1523,24 @@ static void binder_transaction(struct binder_proc *proc,
goto err_bad_offset;
}
off_end = (void *)offp + tr->offsets_size;
+ off_min = 0;
for (; offp < off_end; offp++) {
struct flat_binder_object *fp;
if (*offp > t->buffer->data_size - sizeof(*fp) ||
+ *offp < off_min ||
t->buffer->data_size < sizeof(*fp) ||
!IS_ALIGNED(*offp, sizeof(u32))) {
- binder_user_error("%d:%d got transaction with invalid offset, %lld\n",
- proc->pid, thread->pid, (u64)*offp);
+ binder_user_error("%d:%d got transaction with invalid offset, %lld (min %lld, max %lld)\n",
+ proc->pid, thread->pid, (u64)*offp,
+ (u64)off_min,
+ (u64)(t->buffer->data_size -
+ sizeof(*fp)));
return_error = BR_FAILED_REPLY;
goto err_bad_offset;
}
fp = (struct flat_binder_object *)(t->buffer->data + *offp);
+ off_min = *offp + sizeof(struct flat_binder_object);
switch (fp->type) {
case BINDER_TYPE_BINDER:
case BINDER_TYPE_WEAK_BINDER: {
--
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