From: Saeed Mahameed <saeed@kernel.org>
To: "David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org, Kees Cook <keescook@chromium.org>,
Saeed Mahameed <saeedm@nvidia.com>
Subject: [net 18/18] net/mlx5e: Avoid field-overflowing memcpy()
Date: Tue, 1 Feb 2022 21:04:04 -0800 [thread overview]
Message-ID: <20220202050404.100122-19-saeed@kernel.org> (raw)
In-Reply-To: <20220202050404.100122-1-saeed@kernel.org>
From: Kees Cook <keescook@chromium.org>
In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally writing across neighboring fields.
Use flexible arrays instead of zero-element arrays (which look like they
are always overflowing) and split the cross-field memcpy() into two halves
that can be appropriately bounds-checked by the compiler.
We were doing:
#define ETH_HLEN 14
#define VLAN_HLEN 4
...
#define MLX5E_XDP_MIN_INLINE (ETH_HLEN + VLAN_HLEN)
...
struct mlx5e_tx_wqe *wqe = mlx5_wq_cyc_get_wqe(wq, pi);
...
struct mlx5_wqe_eth_seg *eseg = &wqe->eth;
struct mlx5_wqe_data_seg *dseg = wqe->data;
...
memcpy(eseg->inline_hdr.start, xdptxd->data, MLX5E_XDP_MIN_INLINE);
target is wqe->eth.inline_hdr.start (which the compiler sees as being
2 bytes in size), but copying 18, intending to write across start
(really vlan_tci, 2 bytes). The remaining 16 bytes get written into
wqe->data[0], covering byte_count (4 bytes), lkey (4 bytes), and addr
(8 bytes).
struct mlx5e_tx_wqe {
struct mlx5_wqe_ctrl_seg ctrl; /* 0 16 */
struct mlx5_wqe_eth_seg eth; /* 16 16 */
struct mlx5_wqe_data_seg data[]; /* 32 0 */
/* size: 32, cachelines: 1, members: 3 */
/* last cacheline: 32 bytes */
};
struct mlx5_wqe_eth_seg {
u8 swp_outer_l4_offset; /* 0 1 */
u8 swp_outer_l3_offset; /* 1 1 */
u8 swp_inner_l4_offset; /* 2 1 */
u8 swp_inner_l3_offset; /* 3 1 */
u8 cs_flags; /* 4 1 */
u8 swp_flags; /* 5 1 */
__be16 mss; /* 6 2 */
__be32 flow_table_metadata; /* 8 4 */
union {
struct {
__be16 sz; /* 12 2 */
u8 start[2]; /* 14 2 */
} inline_hdr; /* 12 4 */
struct {
__be16 type; /* 12 2 */
__be16 vlan_tci; /* 14 2 */
} insert; /* 12 4 */
__be32 trailer; /* 12 4 */
}; /* 12 4 */
/* size: 16, cachelines: 1, members: 9 */
/* last cacheline: 16 bytes */
};
struct mlx5_wqe_data_seg {
__be32 byte_count; /* 0 4 */
__be32 lkey; /* 4 4 */
__be64 addr; /* 8 8 */
/* size: 16, cachelines: 1, members: 3 */
/* last cacheline: 16 bytes */
};
So, split the memcpy() so the compiler can reason about the buffer
sizes.
"pahole" shows no size nor member offset changes to struct mlx5e_tx_wqe
nor struct mlx5e_umr_wqe. "objdump -d" shows no meaningful object
code changes (i.e. only source line number induced differences and
optimizations).
Fixes: b5503b994ed5 ("net/mlx5e: XDP TX forwarding support")
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
---
drivers/net/ethernet/mellanox/mlx5/core/en.h | 6 +++---
drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c | 4 +++-
2 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index 812e6810cb3b..c14e06ca64d8 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -224,7 +224,7 @@ static inline int mlx5e_get_max_num_channels(struct mlx5_core_dev *mdev)
struct mlx5e_tx_wqe {
struct mlx5_wqe_ctrl_seg ctrl;
struct mlx5_wqe_eth_seg eth;
- struct mlx5_wqe_data_seg data[0];
+ struct mlx5_wqe_data_seg data[];
};
struct mlx5e_rx_wqe_ll {
@@ -241,8 +241,8 @@ struct mlx5e_umr_wqe {
struct mlx5_wqe_umr_ctrl_seg uctrl;
struct mlx5_mkey_seg mkc;
union {
- struct mlx5_mtt inline_mtts[0];
- struct mlx5_klm inline_klms[0];
+ DECLARE_FLEX_ARRAY(struct mlx5_mtt, inline_mtts);
+ DECLARE_FLEX_ARRAY(struct mlx5_klm, inline_klms);
};
};
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
index 338d65e2c9ce..56e10c84a706 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
@@ -341,8 +341,10 @@ mlx5e_xmit_xdp_frame(struct mlx5e_xdpsq *sq, struct mlx5e_xmit_data *xdptxd,
/* copy the inline part if required */
if (sq->min_inline_mode != MLX5_INLINE_MODE_NONE) {
- memcpy(eseg->inline_hdr.start, xdptxd->data, MLX5E_XDP_MIN_INLINE);
+ memcpy(eseg->inline_hdr.start, xdptxd->data, sizeof(eseg->inline_hdr.start));
eseg->inline_hdr.sz = cpu_to_be16(MLX5E_XDP_MIN_INLINE);
+ memcpy(dseg, xdptxd->data + sizeof(eseg->inline_hdr.start),
+ MLX5E_XDP_MIN_INLINE - sizeof(eseg->inline_hdr.start));
dma_len -= MLX5E_XDP_MIN_INLINE;
dma_addr += MLX5E_XDP_MIN_INLINE;
dseg++;
--
2.34.1
prev parent reply other threads:[~2022-02-02 5:06 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-02 5:03 [pull request][net 00/18] mlx5 fixes 2022-02-01 Saeed Mahameed
2022-02-02 5:03 ` [net 01/18] net/mlx5: Bridge, take rtnl lock in init error handler Saeed Mahameed
2022-02-02 14:30 ` patchwork-bot+netdevbpf
2022-02-02 5:03 ` [net 02/18] net/mlx5: Bridge, ensure dev_name is null-terminated Saeed Mahameed
2022-02-02 5:03 ` [net 03/18] net/mlx5e: TC, Reject rules with drop and modify hdr action Saeed Mahameed
2022-02-02 5:03 ` [net 04/18] net/mlx5e: Fix module EEPROM query Saeed Mahameed
2022-02-02 5:03 ` [net 05/18] net/mlx5: Use del_timer_sync in fw reset flow of halting poll Saeed Mahameed
2022-02-02 5:03 ` [net 06/18] net/mlx5e: TC, Reject rules with forward and drop actions Saeed Mahameed
2022-02-02 5:03 ` [net 07/18] net/mlx5: Fix offloading with ESWITCH_IPV4_TTL_MODIFY_ENABLE Saeed Mahameed
2022-02-02 5:03 ` [net 08/18] net/mlx5: Bridge, Fix devlink deadlock on net namespace deletion Saeed Mahameed
2022-02-02 5:03 ` [net 09/18] net/mlx5e: Fix wrong calculation of header index in HW_GRO Saeed Mahameed
2022-02-02 5:03 ` [net 10/18] net/mlx5e: Fix broken SKB allocation in HW-GRO Saeed Mahameed
2022-02-02 5:03 ` [net 11/18] net/mlx5e: Fix handling of wrong devices during bond netevent Saeed Mahameed
2022-02-02 5:03 ` [net 12/18] net/mlx5: E-Switch, Fix uninitialized variable modact Saeed Mahameed
2022-02-02 5:03 ` [net 13/18] net/mlx5e: Don't treat small ceil values as unlimited in HTB offload Saeed Mahameed
2022-02-02 5:04 ` [net 14/18] net/mlx5e: IPsec: Fix crypto offload for non TCP/UDP encapsulated traffic Saeed Mahameed
2022-02-02 5:04 ` [net 15/18] net/mlx5e: IPsec: Fix tunnel mode crypto offload for non TCP/UDP traffic Saeed Mahameed
2022-02-02 5:04 ` [net 16/18] net/mlx5e: Avoid implicit modify hdr for decap drop rule Saeed Mahameed
2022-02-02 5:04 ` [net 17/18] net/mlx5e: Use struct_group() for memcpy() region Saeed Mahameed
2022-02-02 5:04 ` Saeed Mahameed [this message]
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