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Commit fe7096ab authored by Todd Kjos's avatar Todd Kjos Committed by Todd Kjos
Browse files

UPSTREAM: binder: fix incorrect calculation for num_valid 



commit 16981742717b04644a41052570fb502682a315d2 upstream.

For BINDER_TYPE_PTR and BINDER_TYPE_FDA transactions, the
num_valid local was calculated incorrectly causing the
range check in binder_validate_ptr() to miss out-of-bounds
offsets.

Fixes: bde4a19fc04f ("binder: use userspace pointer as base of buffer space")
Change-Id: Ida77db13d8e5b726f0b14513f55c2b30277338cd
Signed-off-by: default avatarTodd Kjos <tkjos@google.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191213202531.55010-1-tkjos@google.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Bug: 145988638
Signed-off-by: default avatarTodd Kjos <tkjos@google.com>
parent cb87cb11

drivers/android/binder.c

+2 −2
Original line number Diff line number Diff line
@@ -3428,7 +3428,7 @@ static void binder_transaction(struct binder_proc *proc, 
			binder_size_t parent_offset;

			struct binder_fd_array_object *fda =

				to_binder_fd_array_object(hdr);

			size_t num_valid = (buffer_offset - off_start_offset) *

			size_t num_valid = (buffer_offset - off_start_offset) /

						sizeof(binder_size_t);

			struct binder_buffer_object *parent =

				binder_validate_ptr(target_proc, t->buffer,
@@ -3502,7 +3502,7 @@ static void binder_transaction(struct binder_proc *proc, 
				t->buffer->user_data + sg_buf_offset;

			sg_buf_offset += ALIGN(bp->length, sizeof(u64));



			num_valid = (buffer_offset - off_start_offset) *

			num_valid = (buffer_offset - off_start_offset) /

					sizeof(binder_size_t);

			ret = binder_fixup_parent(t, thread, bp,

						  off_start_offset,