[PATCH 4.9 03/86] RDMA/mlx5: Fix integer overflow while resizing CQ

Greg Kroah-Hartman
2018-03-16T15:22:26Z

From: Leon Romanovsky <leonro@mellanox.com>

commit 28e9091e3119933c38933cb8fc48d5618eb784c8 upstream.

The user can provide very large cqe_size which will cause to integer
overflow as it can be seen in the following UBSAN warning:

=======================================================================
UBSAN: Undefined behaviour in drivers/infiniband/hw/mlx5/cq.c:1192:53
signed integer overflow:
64870 * 65536 cannot be represented in type 'int'
CPU: 0 PID: 267 Comm: syzkaller605279 Not tainted 4.15.0+ #90 Hardware
name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
Call Trace:
dump_stack+0xde/0x164
? dma_virt_map_sg+0x22c/0x22c
ubsan_epilogue+0xe/0x81
handle_overflow+0x1f3/0x251
? __ubsan_handle_negate_overflow+0x19b/0x19b
? lock_acquire+0x440/0x440
mlx5_ib_resize_cq+0x17e7/0x1e40
? cyc2ns_read_end+0x10/0x10
? native_read_msr_safe+0x6c/0x9b
? cyc2ns_read_end+0x10/0x10
? mlx5_ib_modify_cq+0x220/0x220
? sched_clock_cpu+0x18/0x200
? lookup_get_idr_uobject+0x200/0x200
? rdma_lookup_get_uobject+0x145/0x2f0
ib_uverbs_resize_cq+0x207/0x3e0
? ib_uverbs_ex_create_cq+0x250/0x250
ib_uverbs_write+0x7f9/0xef0
? cyc2ns_read_end+0x10/0x10
? print_irqtrace_events+0x280/0x280
? ib_uverbs_ex_create_cq+0x250/0x250
? uverbs_devnode+0x110/0x110
? sched_clock_cpu+0x18/0x200
? do_raw_spin_trylock+0x100/0x100
? __lru_cache_add+0x16e/0x290
__vfs_write+0x10d/0x700
? uverbs_devnode+0x110/0x110
? kernel_read+0x170/0x170
? sched_clock_cpu+0x18/0x200
? security_file_permission+0x93/0x260
vfs_write+0x1b0/0x550
SyS_write+0xc7/0x1a0
? SyS_read+0x1a0/0x1a0
? trace_hardirqs_on_thunk+0x1a/0x1c
entry_SYSCALL_64_fastpath+0x1e/0x8b
RIP: 0033:0x433549
RSP: 002b:00007ffe63bd1ea8 EFLAGS: 00000217
=======================================================================

Cc: syzkaller <syzkaller@googlegroups.com>
Cc: <stable@vger.kernel.org> # 3.13
Fixes: bde51583f49b ("IB/mlx5: Add support for resize CQ")
Reported-by: Noa Osherovich <noaos@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/infiniband/hw/mlx5/cq.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/hw/mlx5/cq.c
+++ b/drivers/infiniband/hw/mlx5/cq.c
@@ -1117,7 +1117,12 @@ static int resize_user(struct mlx5_ib_de
if (ucmd.reserved0 || ucmd.reserved1)
return -EINVAL;

- umem = ib_umem_get(context, ucmd.buf_addr, entries * ucmd.cqe_size,
+ /* check multiplication overflow */
+ if (ucmd.cqe_size && SIZE_MAX / ucmd.cqe_size <= entries - 1)
+ return -EINVAL;
+
+ umem = ib_umem_get(context, ucmd.buf_addr,
+ (size_t)ucmd.cqe_size * entries,
IB_ACCESS_LOCAL_WRITE, 1);
if (IS_ERR(umem)) {
err = PTR_ERR(umem);