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Message-ID: <20240619145101.GI690967@kernel.org>
Date: Wed, 19 Jun 2024 15:51:01 +0100
From: Simon Horman <horms@...nel.org>
To: Petr Machata <petrm@...dia.com>
Cc: "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
netdev@...r.kernel.org, Ido Schimmel <idosch@...dia.com>,
mlxsw@...dia.com, Amit Cohen <amcohen@...dia.com>
Subject: Re: [PATCH net 3/3] mlxsw: spectrum_buffers: Fix memory corruptions
on Spectrum-4 systems
On Mon, Jun 17, 2024 at 06:56:02PM +0200, Petr Machata wrote:
> From: Ido Schimmel <idosch@...dia.com>
>
> The following two shared buffer operations make use of the Shared Buffer
> Status Register (SBSR):
>
> # devlink sb occupancy snapshot pci/0000:01:00.0
> # devlink sb occupancy clearmax pci/0000:01:00.0
>
> The register has two masks of 256 bits to denote on which ingress /
> egress ports the register should operate on. Spectrum-4 has more than
> 256 ports, so the register was extended by cited commit with a new
> 'port_page' field.
>
> However, when filling the register's payload, the driver specifies the
> ports as absolute numbers and not relative to the first port of the port
> page, resulting in memory corruptions [1].
>
> Fix by specifying the ports relative to the first port of the port page.
>
> [1]
> BUG: KASAN: slab-use-after-free in mlxsw_sp_sb_occ_snapshot+0xb6d/0xbc0
> Read of size 1 at addr ffff8881068cb00f by task devlink/1566
> [...]
> Call Trace:
> <TASK>
> dump_stack_lvl+0xc6/0x120
> print_report+0xce/0x670
> kasan_report+0xd7/0x110
> mlxsw_sp_sb_occ_snapshot+0xb6d/0xbc0
> mlxsw_devlink_sb_occ_snapshot+0x75/0xb0
> devlink_nl_sb_occ_snapshot_doit+0x1f9/0x2a0
> genl_family_rcv_msg_doit+0x20c/0x300
> genl_rcv_msg+0x567/0x800
> netlink_rcv_skb+0x170/0x450
> genl_rcv+0x2d/0x40
> netlink_unicast+0x547/0x830
> netlink_sendmsg+0x8d4/0xdb0
> __sys_sendto+0x49b/0x510
> __x64_sys_sendto+0xe5/0x1c0
> do_syscall_64+0xc1/0x1d0
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> [...]
> Allocated by task 1:
> kasan_save_stack+0x33/0x60
> kasan_save_track+0x14/0x30
> __kasan_kmalloc+0x8f/0xa0
> copy_verifier_state+0xbc2/0xfb0
> do_check_common+0x2c51/0xc7e0
> bpf_check+0x5107/0x9960
> bpf_prog_load+0xf0e/0x2690
> __sys_bpf+0x1a61/0x49d0
> __x64_sys_bpf+0x7d/0xc0
> do_syscall_64+0xc1/0x1d0
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> Freed by task 1:
> kasan_save_stack+0x33/0x60
> kasan_save_track+0x14/0x30
> kasan_save_free_info+0x3b/0x60
> poison_slab_object+0x109/0x170
> __kasan_slab_free+0x14/0x30
> kfree+0xca/0x2b0
> free_verifier_state+0xce/0x270
> do_check_common+0x4828/0xc7e0
> bpf_check+0x5107/0x9960
> bpf_prog_load+0xf0e/0x2690
> __sys_bpf+0x1a61/0x49d0
> __x64_sys_bpf+0x7d/0xc0
> do_syscall_64+0xc1/0x1d0
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> Fixes: f8538aec88b4 ("mlxsw: Add support for more than 256 ports in SBSR register")
> Cc: Amit Cohen <amcohen@...dia.com>
> Signed-off-by: Ido Schimmel <idosch@...dia.com>
> Reviewed-by: Petr Machata <petrm@...dia.com>
> Signed-off-by: Petr Machata <petrm@...dia.com>
Reviewed-by: Simon Horman <horms@...nel.org>
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