2023-10-25 03:27:37

by Dust Li

Subject: [PATCH net] net/mlx5e: fix double free of encap_header

When mlx5_packet_reformat_alloc() fails, the encap_header allocated in
mlx5e_tc_tun_create_header_ipv4{6} will be released within it. However,
e->encap_header is already set to the previously freed encap_header
before mlx5_packet_reformat_alloc(). As a result, the later
mlx5e_encap_put() will free e->encap_header again, causing a double free
issue.

mlx5e_encap_put()
--> mlx5e_encap_dealloc()
--> kfree(e->encap_header)

This happens when cmd: MLX5_CMD_OP_ALLOC_PACKET_REFORMAT_CONTEXT fail.

This patch fix it by not setting e->encap_header until
mlx5_packet_reformat_alloc() success.

Fixes: d589e785baf5e("net/mlx5e: Allow concurrent creation of encap entries")
Reported-by: Cruz Zhao <[email protected]>
Reported-by: Tianchen Ding <[email protected]>
Signed-off-by: Dust Li <[email protected]>
---
drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
index 00a04fdd756f..8bca696b6658 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
@@ -300,9 +300,6 @@ int mlx5e_tc_tun_create_header_ipv4(struct mlx5e_priv *priv,
if (err)
goto destroy_neigh_entry;

- e->encap_size = ipv4_encap_size;
- e->encap_header = encap_header;
-
if (!(nud_state & NUD_VALID)) {
neigh_event_send(attr.n, NULL);
/* the encap entry will be made valid on neigh update event
@@ -322,6 +319,8 @@ int mlx5e_tc_tun_create_header_ipv4(struct mlx5e_priv *priv,
goto destroy_neigh_entry;
}

+ e->encap_size = ipv4_encap_size;
+ e->encap_header = encap_header;
e->flags |= MLX5_ENCAP_ENTRY_VALID;
mlx5e_rep_queue_neigh_stats_work(netdev_priv(attr.out_dev));
mlx5e_route_lookup_ipv4_put(&attr);
@@ -568,9 +567,6 @@ int mlx5e_tc_tun_create_header_ipv6(struct mlx5e_priv *priv,
if (err)
goto destroy_neigh_entry;

- e->encap_size = ipv6_encap_size;
- e->encap_header = encap_header;
-
if (!(nud_state & NUD_VALID)) {
neigh_event_send(attr.n, NULL);
/* the encap entry will be made valid on neigh update event
@@ -590,6 +586,8 @@ int mlx5e_tc_tun_create_header_ipv6(struct mlx5e_priv *priv,
goto destroy_neigh_entry;
}

+ e->encap_size = ipv6_encap_size;
+ e->encap_header = encap_header;
e->flags |= MLX5_ENCAP_ENTRY_VALID;
mlx5e_rep_queue_neigh_stats_work(netdev_priv(attr.out_dev));
mlx5e_route_lookup_ipv6_put(&attr);
--
2.19.1.6.gb485710b

2023-10-25 09:07:56

by Wojciech Drewek

Subject: Re: [PATCH net] net/mlx5e: fix double free of encap_header

On 25.10.2023 05:27, Dust Li wrote:
> When mlx5_packet_reformat_alloc() fails, the encap_header allocated in
> mlx5e_tc_tun_create_header_ipv4{6} will be released within it. However,
> e->encap_header is already set to the previously freed encap_header
> before mlx5_packet_reformat_alloc(). As a result, the later
> mlx5e_encap_put() will free e->encap_header again, causing a double free
> issue.
>
> mlx5e_encap_put()
> --> mlx5e_encap_dealloc()
> --> kfree(e->encap_header)

nit: I think it should mlx5e_encap_put_locked not mlx5e_encap_put to be precise.

>
> This happens when cmd: MLX5_CMD_OP_ALLOC_PACKET_REFORMAT_CONTEXT fail.
>
> This patch fix it by not setting e->encap_header until
> mlx5_packet_reformat_alloc() success.
>
> Fixes: d589e785baf5e("net/mlx5e: Allow concurrent creation of encap entries")
> Reported-by: Cruz Zhao <[email protected]>
> Reported-by: Tianchen Ding <[email protected]>
> Signed-off-by: Dust Li <[email protected]>
> ---

Reviewed-by: Wojciech Drewek <[email protected]>

> drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c | 10 ++++------
> 1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
> index 00a04fdd756f..8bca696b6658 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
> @@ -300,9 +300,6 @@ int mlx5e_tc_tun_create_header_ipv4(struct mlx5e_priv *priv,
> if (err)
> goto destroy_neigh_entry;
>
> - e->encap_size = ipv4_encap_size;
> - e->encap_header = encap_header;
> -
> if (!(nud_state & NUD_VALID)) {
> neigh_event_send(attr.n, NULL);
> /* the encap entry will be made valid on neigh update event
> @@ -322,6 +319,8 @@ int mlx5e_tc_tun_create_header_ipv4(struct mlx5e_priv *priv,
> goto destroy_neigh_entry;
> }
>
> + e->encap_size = ipv4_encap_size;
> + e->encap_header = encap_header;
> e->flags |= MLX5_ENCAP_ENTRY_VALID;
> mlx5e_rep_queue_neigh_stats_work(netdev_priv(attr.out_dev));
> mlx5e_route_lookup_ipv4_put(&attr);
> @@ -568,9 +567,6 @@ int mlx5e_tc_tun_create_header_ipv6(struct mlx5e_priv *priv,
> if (err)
> goto destroy_neigh_entry;
>
> - e->encap_size = ipv6_encap_size;
> - e->encap_header = encap_header;
> -
> if (!(nud_state & NUD_VALID)) {
> neigh_event_send(attr.n, NULL);
> /* the encap entry will be made valid on neigh update event
> @@ -590,6 +586,8 @@ int mlx5e_tc_tun_create_header_ipv6(struct mlx5e_priv *priv,
> goto destroy_neigh_entry;
> }
>
> + e->encap_size = ipv6_encap_size;
> + e->encap_header = encap_header;
> e->flags |= MLX5_ENCAP_ENTRY_VALID;
> mlx5e_rep_queue_neigh_stats_work(netdev_priv(attr.out_dev));
> mlx5e_route_lookup_ipv6_put(&attr);

2023-10-26 23:00:18

by Saeed Mahameed

Subject: Re: [PATCH net] net/mlx5e: fix double free of encap_header

On 25 Oct 11:27, Dust Li wrote:
>When mlx5_packet_reformat_alloc() fails, the encap_header allocated in
>mlx5e_tc_tun_create_header_ipv4{6} will be released within it. However,
>e->encap_header is already set to the previously freed encap_header
>before mlx5_packet_reformat_alloc(). As a result, the later
>mlx5e_encap_put() will free e->encap_header again, causing a double free
>issue.
>
>mlx5e_encap_put()
> --> mlx5e_encap_dealloc()
> --> kfree(e->encap_header)
>
>This happens when cmd: MLX5_CMD_OP_ALLOC_PACKET_REFORMAT_CONTEXT fail.
>
>This patch fix it by not setting e->encap_header until
>mlx5_packet_reformat_alloc() success.
>
>Fixes: d589e785baf5e("net/mlx5e: Allow concurrent creation of encap entries")
>Reported-by: Cruz Zhao <[email protected]>
>Reported-by: Tianchen Ding <[email protected]>
>Signed-off-by: Dust Li <[email protected]>

Applied to net-mlx5

2023-10-27 06:59:23

by Dust Li

Subject: Re: [PATCH net] net/mlx5e: fix double free of encap_header

On Wed, Oct 25, 2023 at 11:06:25AM +0200, Wojciech Drewek wrote:
>
>
>On 25.10.2023 05:27, Dust Li wrote:
>> When mlx5_packet_reformat_alloc() fails, the encap_header allocated in
>> mlx5e_tc_tun_create_header_ipv4{6} will be released within it. However,
>> e->encap_header is already set to the previously freed encap_header
>> before mlx5_packet_reformat_alloc(). As a result, the later
>> mlx5e_encap_put() will free e->encap_header again, causing a double free
>> issue.
>>
>> mlx5e_encap_put()
>> --> mlx5e_encap_dealloc()
>> --> kfree(e->encap_header)
>
>nit: I think it should mlx5e_encap_put_locked not mlx5e_encap_put to be precise.

You are right.

The original version is mlx5e_encap_put, I mistakenly used the name of
the old version when doing git blame.

Best regards,
Dust


>
>>
>> This happens when cmd: MLX5_CMD_OP_ALLOC_PACKET_REFORMAT_CONTEXT fail.
>>
>> This patch fix it by not setting e->encap_header until
>> mlx5_packet_reformat_alloc() success.
>>
>> Fixes: d589e785baf5e("net/mlx5e: Allow concurrent creation of encap entries")
>> Reported-by: Cruz Zhao <[email protected]>
>> Reported-by: Tianchen Ding <[email protected]>
>> Signed-off-by: Dust Li <[email protected]>
>> ---
>
>Reviewed-by: Wojciech Drewek <[email protected]>
>
>> drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c | 10 ++++------
>> 1 file changed, 4 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
>> index 00a04fdd756f..8bca696b6658 100644
>> --- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
>> @@ -300,9 +300,6 @@ int mlx5e_tc_tun_create_header_ipv4(struct mlx5e_priv *priv,
>> if (err)
>> goto destroy_neigh_entry;
>>
>> - e->encap_size = ipv4_encap_size;
>> - e->encap_header = encap_header;
>> -
>> if (!(nud_state & NUD_VALID)) {
>> neigh_event_send(attr.n, NULL);
>> /* the encap entry will be made valid on neigh update event
>> @@ -322,6 +319,8 @@ int mlx5e_tc_tun_create_header_ipv4(struct mlx5e_priv *priv,
>> goto destroy_neigh_entry;
>> }
>>
>> + e->encap_size = ipv4_encap_size;
>> + e->encap_header = encap_header;
>> e->flags |= MLX5_ENCAP_ENTRY_VALID;
>> mlx5e_rep_queue_neigh_stats_work(netdev_priv(attr.out_dev));
>> mlx5e_route_lookup_ipv4_put(&attr);
>> @@ -568,9 +567,6 @@ int mlx5e_tc_tun_create_header_ipv6(struct mlx5e_priv *priv,
>> if (err)
>> goto destroy_neigh_entry;
>>
>> - e->encap_size = ipv6_encap_size;
>> - e->encap_header = encap_header;
>> -
>> if (!(nud_state & NUD_VALID)) {
>> neigh_event_send(attr.n, NULL);
>> /* the encap entry will be made valid on neigh update event
>> @@ -590,6 +586,8 @@ int mlx5e_tc_tun_create_header_ipv6(struct mlx5e_priv *priv,
>> goto destroy_neigh_entry;
>> }
>>
>> + e->encap_size = ipv6_encap_size;
>> + e->encap_header = encap_header;
>> e->flags |= MLX5_ENCAP_ENTRY_VALID;
>> mlx5e_rep_queue_neigh_stats_work(netdev_priv(attr.out_dev));
>> mlx5e_route_lookup_ipv6_put(&attr);