| From 9f2801da8ffa98255156ee9832f7ebb1d06971c4 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Sun, 25 Apr 2021 18:16:47 -0700 |
| Subject: RDMA/siw: Fix a use after free in siw_alloc_mr |
| |
| From: Lv Yunlong <lyl2019@mail.ustc.edu.cn> |
| |
| [ Upstream commit 3093ee182f01689b89e9f8797b321603e5de4f63 ] |
| |
| Our code analyzer reported a UAF. |
| |
| In siw_alloc_mr(), it calls siw_mr_add_mem(mr,..). In the implementation of |
| siw_mr_add_mem(), mem is assigned to mr->mem and then mem is freed via |
| kfree(mem) if xa_alloc_cyclic() failed. Here, mr->mem still point to a |
| freed object. After, the execution continue up to the err_out branch of |
| siw_alloc_mr, and the freed mr->mem is used in siw_mr_drop_mem(mr). |
| |
| My patch moves "mr->mem = mem" behind the if (xa_alloc_cyclic(..)<0) {} |
| section, to avoid the uaf. |
| |
| Fixes: 2251334dcac9 ("rdma/siw: application buffer management") |
| Link: https://lore.kernel.org/r/20210426011647.3561-1-lyl2019@mail.ustc.edu.cn |
| Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn> |
| Reviewed-by: Bernard Metzler <bmt@zurich.ihm.com> |
| Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/infiniband/sw/siw/siw_mem.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| diff --git a/drivers/infiniband/sw/siw/siw_mem.c b/drivers/infiniband/sw/siw/siw_mem.c |
| index 34a910cf0edb..61c17db70d65 100644 |
| --- a/drivers/infiniband/sw/siw/siw_mem.c |
| +++ b/drivers/infiniband/sw/siw/siw_mem.c |
| @@ -106,8 +106,6 @@ int siw_mr_add_mem(struct siw_mr *mr, struct ib_pd *pd, void *mem_obj, |
| mem->perms = rights & IWARP_ACCESS_MASK; |
| kref_init(&mem->ref); |
| |
| - mr->mem = mem; |
| - |
| get_random_bytes(&next, 4); |
| next &= 0x00ffffff; |
| |
| @@ -116,6 +114,8 @@ int siw_mr_add_mem(struct siw_mr *mr, struct ib_pd *pd, void *mem_obj, |
| kfree(mem); |
| return -ENOMEM; |
| } |
| + |
| + mr->mem = mem; |
| /* Set the STag index part */ |
| mem->stag = id << 8; |
| mr->base_mr.lkey = mr->base_mr.rkey = mem->stag; |
| -- |
| 2.30.2 |
| |