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authorYann Droneaud <ydroneaud@opteya.com>2014-05-05 19:33:21 +0200
committerRoland Dreier <roland@purestorage.com>2014-05-27 11:53:13 -0700
commita8237b32a3faab155a5dc8f886452147ce73da3e (patch)
treed1e5ab19dc27bf0f00fa0e59c61444ff9162000c /drivers/infiniband/hw/mlx5/cq.c
parenta74d24168d2df78e7a532567eb0e7538e6b09568 (diff)
IB/mlx5: add missing padding at end of struct mlx5_ib_create_cq
The i386 ABI disagrees with most other ABIs regarding alignment of data type larger than 4 bytes: on most ABIs a padding must be added at end of the structures, while it is not required on i386. So for most ABI struct mlx5_ib_create_cq get padded to be aligned on a 8 bytes multiple, while for i386, such padding is not added. The tool pahole can be used to find such implicit padding: $ pahole --anon_include \ --nested_anon_include \ --recursive \ --class_name mlx5_ib_create_cq \ drivers/infiniband/hw/mlx5/mlx5_ib.o Then, structure layout can be compared between i386 and x86_64: +++ obj-i386/drivers/infiniband/hw/mlx5/mlx5_ib.o.pahole.txt 2014-03-28 11:43:07.386413682 +0100 --- obj-x86_64/drivers/infiniband/hw/mlx5/mlx5_ib.o.pahole.txt 2014-03-27 13:06:17.788472721 +0100 @@ -34,9 +34,8 @@ struct mlx5_ib_create_cq { __u64 db_addr; /* 8 8 */ __u32 cqe_size; /* 16 4 */ - /* size: 20, cachelines: 1, members: 3 */ - /* last cacheline: 20 bytes */ + /* size: 24, cachelines: 1, members: 3 */ + /* padding: 4 */ + /* last cacheline: 24 bytes */ }; This ABI disagreement will make an x86_64 kernel try to read past the buffer provided by an i386 binary. When boundary check will be implemented, a x86_64 kernel will refuse to read past the i386 userspace provided buffer and the uverb will fail. Anyway, if the structure lies in memory on a page boundary and next page is not mapped, ib_copy_from_udata() will fail when trying to read the 4 bytes of padding and the uverb will fail. This patch makes create_cq_user() takes care of the input data size to handle the case where no padding is provided. This way, x86_64 kernel will be able to handle struct mlx5_ib_create_cq as sent by unpatched and patched i386 libmlx5. Link: http://marc.info/?i=cover.1399309513.git.ydroneaud@opteya.com Cc: <stable@vger.kernel.org> Fixes: e126ba97dba9e ("mlx5: Add driver for Mellanox Connect-IB adapter") Signed-off-by: Yann Droneaud <ydroneaud@opteya.com> Signed-off-by: Roland Dreier <roland@purestorage.com>
Diffstat (limited to 'drivers/infiniband/hw/mlx5/cq.c')
-rw-r--r--drivers/infiniband/hw/mlx5/cq.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/infiniband/hw/mlx5/cq.c b/drivers/infiniband/hw/mlx5/cq.c
index 62bb6b49dc1..8ae4f896cb4 100644
--- a/drivers/infiniband/hw/mlx5/cq.c
+++ b/drivers/infiniband/hw/mlx5/cq.c
@@ -32,6 +32,7 @@
#include <linux/kref.h>
#include <rdma/ib_umem.h>
+#include <rdma/ib_user_verbs.h>
#include "mlx5_ib.h"
#include "user.h"
@@ -602,14 +603,24 @@ static int create_cq_user(struct mlx5_ib_dev *dev, struct ib_udata *udata,
int *cqe_size, int *index, int *inlen)
{
struct mlx5_ib_create_cq ucmd;
+ size_t ucmdlen;
int page_shift;
int npages;
int ncont;
int err;
- if (ib_copy_from_udata(&ucmd, udata, sizeof(ucmd)))
+ ucmdlen =
+ (udata->inlen - sizeof(struct ib_uverbs_cmd_hdr) <
+ sizeof(ucmd)) ? (sizeof(ucmd) -
+ sizeof(ucmd.reserved)) : sizeof(ucmd);
+
+ if (ib_copy_from_udata(&ucmd, udata, ucmdlen))
return -EFAULT;
+ if (ucmdlen == sizeof(ucmd) &&
+ ucmd.reserved != 0)
+ return -EINVAL;
+
if (ucmd.cqe_size != 64 && ucmd.cqe_size != 128)
return -EINVAL;