From 212265e5ad726ed7fd2ec7d61d36d9e0b0d3e655 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= Date: Tue, 9 Feb 2016 21:05:32 -0800 Subject: [PATCH] android: binder: More offset validation MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Make sure offsets don't point to overlapping flat_binder_object structs. Cc: Colin Cross Cc: Arve Hjønnevåg Cc: Dmitry Shmidt Cc: Rom Lemarchand Cc: Serban Constantinescu Cc: Greg Kroah-Hartman Cc: Android Kernel Team Signed-off-by: Dmitry Shmidt Signed-off-by: John Stultz Signed-off-by: Greg Kroah-Hartman --- 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 a39e85f9efa9..1db376184955 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: { -- 2.30.2