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ethtool: Remove link_mode param and derive link params from driver

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Some drivers clear the 'ethtool_link_ksettings' struct in their
get_link_ksettings() callback, before populating it with actual values.
Such drivers will set the new 'link_mode' field to zero, resulting in
user space receiving wrong link mode information given that zero is a
valid value for the field.

Another problem is that some drivers (notably tun) can report random
values in the 'link_mode' field. This can result in a general protection
fault when the field is used as an index to the 'link_mode_params' array
[1].

This happens because such drivers implement their set_link_ksettings()
callback by simply overwriting their private copy of
'ethtool_link_ksettings' struct with the one they get from the stack,
which is not always properly initialized.

Fix these problems by removing 'link_mode' from 'ethtool_link_ksettings'
and instead have drivers call ethtool_params_from_link_mode() with the
current link mode. The function will derive the link parameters (e.g.,
speed) from the link mode and fill them in the 'ethtool_link_ksettings'
struct.

v3:
	* Remove link_mode parameter and derive the link parameters in
	  the driver instead of passing link_mode parameter to ethtool
	  and derive it there.

v2:
	* Introduce 'cap_link_mode_supported' instead of adding a
	  validity field to 'ethtool_link_ksettings' struct.

[1]
general protection fault, probably for non-canonical address 0xdffffc00f14cc32c: 0000 [#1] PREEMPT SMP KASAN
KASAN: probably user-memory-access in range [0x000000078a661960-0x000000078a661967]
CPU: 0 PID: 8452 Comm: syz-executor360 Not tainted 5.11.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__ethtool_get_link_ksettings+0x1a3/0x3a0 net/ethtool/ioctl.c:446
Code: b7 3e fa 83 fd ff 0f 84 30 01 00 00 e8 16 b0 3e fa 48 8d 3c ed 60 d5 69 8a 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03
+38 d0 7c 08 84 d2 0f 85 b9
RSP: 0018:ffffc900019df7a0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff888026136008 RCX: 0000000000000000
RDX: 00000000f14cc32c RSI: ffffffff873439ca RDI: 000000078a661960
RBP: 00000000ffff8880 R08: 00000000ffffffff R09: ffff88802613606f
R10: ffffffff873439bc R11: 0000000000000000 R12: 0000000000000000
R13: ffff88802613606c R14: ffff888011d0c210 R15: ffff888011d0c210
FS:  0000000000749300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004b60f0 CR3: 00000000185c2000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 linkinfo_prepare_data+0xfd/0x280 net/ethtool/linkinfo.c:37
 ethnl_default_notify+0x1dc/0x630 net/ethtool/netlink.c:586
 ethtool_notify+0xbd/0x1f0 net/ethtool/netlink.c:656
 ethtool_set_link_ksettings+0x277/0x330 net/ethtool/ioctl.c:620
 dev_ethtool+0x2b35/0x45d0 net/ethtool/ioctl.c:2842
 dev_ioctl+0x463/0xb70 net/core/dev_ioctl.c:440
 sock_do_ioctl+0x148/0x2d0 net/socket.c:1060
 sock_ioctl+0x477/0x6a0 net/socket.c:1177
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: c8907043c6 ("ethtool: Get link mode in use instead of speed and duplex parameters")
Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Danielle Ratson 2021-04-07 13:06:51 +03:00 committed by David S. Miller
parent bb58023bee
commit a975d7d8a3
4 changed files with 39 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/net/ethernet/mellanox/mlxsw/spectrum_ethtool.c
View File

@ -1230,16 +1230,22 @@ mlxsw_sp1_from_ptys_link_mode(struct mlxsw_sp *mlxsw_sp, bool carrier_ok,
u32 ptys_eth_proto,
struct ethtool_link_ksettings *cmd)
{
struct mlxsw_sp1_port_link_mode link;
int i;
cmd->link_mode = -1;
cmd->base.speed = SPEED_UNKNOWN;
cmd->base.duplex = DUPLEX_UNKNOWN;
cmd->lanes = 0;
if (!carrier_ok)
return;
for (i = 0; i < MLXSW_SP1_PORT_LINK_MODE_LEN; i++) {
if (ptys_eth_proto & mlxsw_sp1_port_link_mode[i].mask)
cmd->link_mode = mlxsw_sp1_port_link_mode[i].mask_ethtool;
if (ptys_eth_proto & mlxsw_sp1_port_link_mode[i].mask) {
link = mlxsw_sp1_port_link_mode[i];
ethtool_params_from_link_mode(cmd,
link.mask_ethtool);
}
}
}
@ -1672,7 +1678,9 @@ mlxsw_sp2_from_ptys_link_mode(struct mlxsw_sp *mlxsw_sp, bool carrier_ok,
struct mlxsw_sp2_port_link_mode link;
int i;
cmd->link_mode = -1;
cmd->base.speed = SPEED_UNKNOWN;
cmd->base.duplex = DUPLEX_UNKNOWN;
cmd->lanes = 0;
if (!carrier_ok)
return;
@ -1680,7 +1688,8 @@ mlxsw_sp2_from_ptys_link_mode(struct mlxsw_sp *mlxsw_sp, bool carrier_ok,
for (i = 0; i < MLXSW_SP2_PORT_LINK_MODE_LEN; i++) {
if (ptys_eth_proto & mlxsw_sp2_port_link_mode[i].mask) {
link = mlxsw_sp2_port_link_mode[i];
cmd->link_mode = link.mask_ethtool[1];
ethtool_params_from_link_mode(cmd,
link.mask_ethtool[1]);
}
}
}

9
include/linux/ethtool.h
View File

@ -127,7 +127,6 @@ struct ethtool_link_ksettings {
__ETHTOOL_DECLARE_LINK_MODE_MASK(lp_advertising);
} link_modes;
u32 lanes;
enum ethtool_link_mode_bit_indices link_mode;
};
/**
@ -574,4 +573,12 @@ struct ethtool_phy_ops {
*/
void ethtool_set_ethtool_phy_ops(const struct ethtool_phy_ops *ops);
/*
* ethtool_params_from_link_mode - Derive link parameters from a given link mode
* @link_ksettings: Link parameters to be derived from the link mode
* @link_mode: Link mode
*/
void
ethtool_params_from_link_mode(struct ethtool_link_ksettings *link_ksettings,
enum ethtool_link_mode_bit_indices link_mode);
#endif /* _LINUX_ETHTOOL_H */

16
net/ethtool/common.c
View File

@ -562,3 +562,19 @@ void ethtool_set_ethtool_phy_ops(const struct ethtool_phy_ops *ops)
rtnl_unlock();
}
EXPORT_SYMBOL_GPL(ethtool_set_ethtool_phy_ops);
void
ethtool_params_from_link_mode(struct ethtool_link_ksettings *link_ksettings,
enum ethtool_link_mode_bit_indices link_mode)
{
const struct link_mode_info *link_info;
if (WARN_ON_ONCE(link_mode >= __ETHTOOL_LINK_MODE_MASK_NBITS))
return;
link_info = &link_mode_params[link_mode];
link_ksettings->base.speed = link_info->speed;
link_ksettings->lanes = link_info->lanes;
link_ksettings->base.duplex = link_info->duplex;
}
EXPORT_SYMBOL_GPL(ethtool_params_from_link_mode);

18
net/ethtool/ioctl.c
View File

@ -426,29 +426,13 @@ struct ethtool_link_usettings {
int __ethtool_get_link_ksettings(struct net_device *dev,
struct ethtool_link_ksettings *link_ksettings)
{
const struct link_mode_info *link_info;
int err;
ASSERT_RTNL();
if (!dev->ethtool_ops->get_link_ksettings)
return -EOPNOTSUPP;
memset(link_ksettings, 0, sizeof(*link_ksettings));
link_ksettings->link_mode = -1;
err = dev->ethtool_ops->get_link_ksettings(dev, link_ksettings);
if (err)
return err;
if (link_ksettings->link_mode != -1) {
link_info = &link_mode_params[link_ksettings->link_mode];
link_ksettings->base.speed = link_info->speed;
link_ksettings->lanes = link_info->lanes;
link_ksettings->base.duplex = link_info->duplex;
}
return 0;
return dev->ethtool_ops->get_link_ksettings(dev, link_ksettings);
}
EXPORT_SYMBOL(__ethtool_get_link_ksettings);