The patch below does not apply to the 4.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 05f58ceba123bdb420cf44c6ea04b6db467edd1c Mon Sep 17 00:00:00 2001

From: Leon Romanovsky leonro@mellanox.com Date: Sun, 8 Jul 2018 13:50:21 +0300 Subject: [PATCH] RDMA/mlx5: Check that supplied blue flame index doesn't overflow

User's supplied index is checked again total number of system pages, but this number already includes num_static_sys_pages, so addition of that value to supplied index causes to below error while trying to access sys_pages[].

BUG: KASAN: slab-out-of-bounds in bfregn_to_uar_index+0x34f/0x400 Read of size 4 at addr ffff880065561904 by task syz-executor446/314

CPU: 0 PID: 314 Comm: syz-executor446 Not tainted 4.18.0-rc1+ #256 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.0-0-g63451fca13-prebuilt.qemu-project.org 04/01/2014 Call Trace: dump_stack+0xef/0x17e print_address_description+0x83/0x3b0 kasan_report+0x18d/0x4d0 bfregn_to_uar_index+0x34f/0x400 create_user_qp+0x272/0x227d create_qp_common+0x32eb/0x43e0 mlx5_ib_create_qp+0x379/0x1ca0 create_qp.isra.5+0xc94/0x22d0 ib_uverbs_create_qp+0x21b/0x2a0 ib_uverbs_write+0xc2c/0x1010 vfs_write+0x1b0/0x550 ksys_write+0xc6/0x1a0 do_syscall_64+0xa7/0x590 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x433679 Code: fd ff 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b 91 fd ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff2b3d8e48 EFLAGS: 00000217 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00000000004002f8 RCX: 0000000000433679 RDX: 0000000000000040 RSI: 0000000020000240 RDI: 0000000000000003 RBP: 00000000006d4018 R08: 00000000004002f8 R09: 00000000004002f8 R10: 00000000004002f8 R11: 0000000000000217 R12: 0000000000000000 R13: 000000000040cb00 R14: 000000000040cb90 R15: 0000000000000006

Allocated by task 314: kasan_kmalloc+0xa0/0xd0 __kmalloc+0x1a9/0x510 mlx5_ib_alloc_ucontext+0x966/0x2620 ib_uverbs_get_context+0x23f/0xa60 ib_uverbs_write+0xc2c/0x1010 __vfs_write+0x10d/0x720 vfs_write+0x1b0/0x550 ksys_write+0xc6/0x1a0 do_syscall_64+0xa7/0x590 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 1: __kasan_slab_free+0x12e/0x180 kfree+0x159/0x630 kvfree+0x37/0x50 single_release+0x8e/0xf0 __fput+0x2d8/0x900 task_work_run+0x102/0x1f0 exit_to_usermode_loop+0x159/0x1c0 do_syscall_64+0x408/0x590 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff880065561100 which belongs to the cache kmalloc-4096 of size 4096 The buggy address is located 2052 bytes inside of 4096-byte region [ffff880065561100, ffff880065562100) The buggy address belongs to the page: page:ffffea0001955800 count:1 mapcount:0 mapping:ffff88006c402480 index:0x0 compound_mapcount: 0 flags: 0x4000000000008100(slab|head) raw: 4000000000008100 ffffea0001a7c000 0000000200000002 ffff88006c402480 raw: 0000000000000000 0000000080070007 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected

Memory state around the buggy address: ffff880065561800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff880065561880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

ffff880065561900: 04 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

^ ffff880065561980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff880065561a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

Cc: stable@vger.kernel.org # 4.15 Fixes: 1ee47ab3e8d8 ("IB/mlx5: Enable QP creation with a given blue flame index") Reported-by: Noa Osherovich noaos@mellanox.com Signed-off-by: Leon Romanovsky leonro@mellanox.com Signed-off-by: Jason Gunthorpe jgg@mellanox.com

diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h index 93087409f4b8..04a5d82c9cf3 100644 --- a/drivers/infiniband/hw/mlx5/mlx5_ib.h +++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h @@ -1330,6 +1330,6 @@ unsigned long mlx5_ib_get_xlt_emergency_page(void); void mlx5_ib_put_xlt_emergency_page(void);

int bfregn_to_uar_index(struct mlx5_ib_dev *dev, - struct mlx5_bfreg_info *bfregi, int bfregn, + struct mlx5_bfreg_info *bfregi, u32 bfregn, bool dyn_bfreg); #endif /* MLX5_IB_H */ diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c index 51e68ca20215..d4414015b64f 100644 --- a/drivers/infiniband/hw/mlx5/qp.c +++ b/drivers/infiniband/hw/mlx5/qp.c @@ -631,22 +631,23 @@ static void mlx5_ib_unlock_cqs(struct mlx5_ib_cq *send_cq, struct mlx5_ib_cq *recv_cq);

int bfregn_to_uar_index(struct mlx5_ib_dev *dev, - struct mlx5_bfreg_info *bfregi, int bfregn, + struct mlx5_bfreg_info *bfregi, u32 bfregn, bool dyn_bfreg) { - int bfregs_per_sys_page; - int index_of_sys_page; - int offset; + unsigned int bfregs_per_sys_page; + u32 index_of_sys_page; + u32 offset;

bfregs_per_sys_page = get_uars_per_sys_page(dev, bfregi->lib_uar_4k) * MLX5_NON_FP_BFREGS_PER_UAR; index_of_sys_page = bfregn / bfregs_per_sys_page;

- if (index_of_sys_page >= bfregi->num_sys_pages) - return -EINVAL; - if (dyn_bfreg) { index_of_sys_page += bfregi->num_static_sys_pages; + + if (index_of_sys_page >= bfregi->num_sys_pages) + return -EINVAL; + if (bfregn > bfregi->num_dyn_bfregs || bfregi->sys_pages[index_of_sys_page] == MLX5_IB_INVALID_UAR_INDEX) { mlx5_ib_dbg(dev, "Invalid dynamic uar index\n");