From 43bc889380c2ad9aa230eccc03a15cc52cf710d4 Mon Sep 17 00:00:00 2001 From: Yann Droneaud Date: Mon, 5 May 2014 19:33:22 +0200 Subject: [PATCH] IB/mlx5: add missing padding at end of struct mlx5_ib_create_srq 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 ABIs struct mlx5_ib_create_srq gets implicitly padded to be aligned on a 8 bytes multiple, while for i386, such padding is not added. Tool pahole could be used to find such implicit padding: $ pahole --anon_include \ --nested_anon_include \ --recursive \ --class_name mlx5_ib_create_srq \ 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 @@ -69,7 +68,6 @@ struct mlx5_ib_create_srq { __u64 db_addr; /* 8 8 */ __u32 flags; /* 16 4 */ - /* size: 20, cachelines: 1, members: 3 */ - /* last cacheline: 20 bytes */ + /* size: 24, cachelines: 1, members: 3 */ + /* padding: 4 */ + /* last cacheline: 24 bytes */ }; 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, the x86_64 kernel will refuse to read past the i386 userspace provided buffer and the uverb will fail. Anyway, if the structure lay in memory on a page boundary and next page is not mapped, ib_copy_from_udata() will fail and the uverb will fail. This patch makes create_srq_user() takes care of the input data size to handle the case where no padding was provided. This way, x86_64 kernel will be able to handle struct mlx5_ib_create_srq as sent by unpatched and patched i386 libmlx5. Link: http://marc.info/?i=cover.1399309513.git.ydroneaud@opteya.com Cc: Fixes: e126ba97dba9e ("mlx5: Add driver for Mellanox Connect-IB adapter") Signed-off-by: Yann Droneaud Signed-off-by: Roland Dreier --- drivers/infiniband/hw/mlx5/srq.c | 14 +++++++++++++- drivers/infiniband/hw/mlx5/user.h | 1 + 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/hw/mlx5/srq.c b/drivers/infiniband/hw/mlx5/srq.c index 210b3eaf188a..384af6dec5eb 100644 --- a/drivers/infiniband/hw/mlx5/srq.c +++ b/drivers/infiniband/hw/mlx5/srq.c @@ -35,6 +35,7 @@ #include #include #include +#include #include "mlx5_ib.h" #include "user.h" @@ -78,16 +79,27 @@ static int create_srq_user(struct ib_pd *pd, struct mlx5_ib_srq *srq, { struct mlx5_ib_dev *dev = to_mdev(pd->device); struct mlx5_ib_create_srq ucmd; + size_t ucmdlen; int err; int npages; int page_shift; int ncont; u32 offset; - 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)) { mlx5_ib_dbg(dev, "failed copy udata\n"); return -EFAULT; } + + if (ucmdlen == sizeof(ucmd) && + ucmd.reserved != 0) + return -EINVAL; + srq->wq_sig = !!(ucmd.flags & MLX5_SRQ_FLAG_SIGNATURE); srq->umem = ib_umem_get(pd->uobject->context, ucmd.buf_addr, buf_size, diff --git a/drivers/infiniband/hw/mlx5/user.h b/drivers/infiniband/hw/mlx5/user.h index d44ecd2c2faf..d0ba264ac1ed 100644 --- a/drivers/infiniband/hw/mlx5/user.h +++ b/drivers/infiniband/hw/mlx5/user.h @@ -110,6 +110,7 @@ struct mlx5_ib_create_srq { __u64 buf_addr; __u64 db_addr; __u32 flags; + __u32 reserved; /* explicit padding (optional on i386) */ }; struct mlx5_ib_create_srq_resp { -- 2.20.1