* [PATCH bpf] xdp: Reset prog in dev_change_xdp_fd when fd is negative
@ 2020-04-12 13:32 David Ahern
2020-04-12 18:11 ` Jakub Kicinski
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: David Ahern @ 2020-04-12 13:32 UTC (permalink / raw)
To: daniel, ast; +Cc: netdev, David Ahern, Toke Høiland-Jørgensen
From: David Ahern <dsahern@gmail.com>
The commit mentioned in the Fixes tag reuses the local prog variable
when looking up an expected_fd. The variable is not reset when fd < 0
causing a detach with the expected_fd set to actually call
dev_xdp_install for the existing program. The end result is that the
detach does not happen.
Fixes: 92234c8f15c8 ("xdp: Support specifying expected existing program when attaching XDP")
Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Toke Høiland-Jørgensen <toke@redhat.com>
---
net/core/dev.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index df8097b8e286..522288177bbd 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -8667,8 +8667,8 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
const struct net_device_ops *ops = dev->netdev_ops;
enum bpf_netdev_command query;
u32 prog_id, expected_id = 0;
- struct bpf_prog *prog = NULL;
bpf_op_t bpf_op, bpf_chk;
+ struct bpf_prog *prog;
bool offload;
int err;
@@ -8734,6 +8734,7 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
} else {
if (!prog_id)
return 0;
+ prog = NULL;
}
err = dev_xdp_install(dev, bpf_op, extack, flags, prog);
--
2.20.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH bpf] xdp: Reset prog in dev_change_xdp_fd when fd is negative
2020-04-12 13:32 [PATCH bpf] xdp: Reset prog in dev_change_xdp_fd when fd is negative David Ahern
@ 2020-04-12 18:11 ` Jakub Kicinski
2020-04-13 22:08 ` Alexei Starovoitov
2020-04-14 7:17 ` Toke Høiland-Jørgensen
2 siblings, 0 replies; 5+ messages in thread
From: Jakub Kicinski @ 2020-04-12 18:11 UTC (permalink / raw)
To: David Ahern
Cc: daniel, ast, netdev, David Ahern, Toke Høiland-Jørgensen
On Sun, 12 Apr 2020 07:32:04 -0600 David Ahern wrote:
> From: David Ahern <dsahern@gmail.com>
>
> The commit mentioned in the Fixes tag reuses the local prog variable
> when looking up an expected_fd. The variable is not reset when fd < 0
> causing a detach with the expected_fd set to actually call
> dev_xdp_install for the existing program. The end result is that the
> detach does not happen.
>
> Fixes: 92234c8f15c8 ("xdp: Support specifying expected existing program when attaching XDP")
> Signed-off-by: David Ahern <dsahern@gmail.com>
> Cc: Toke Høiland-Jørgensen <toke@redhat.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH bpf] xdp: Reset prog in dev_change_xdp_fd when fd is negative
2020-04-12 13:32 [PATCH bpf] xdp: Reset prog in dev_change_xdp_fd when fd is negative David Ahern
2020-04-12 18:11 ` Jakub Kicinski
@ 2020-04-13 22:08 ` Alexei Starovoitov
2020-04-14 7:17 ` Toke Høiland-Jørgensen
2 siblings, 0 replies; 5+ messages in thread
From: Alexei Starovoitov @ 2020-04-13 22:08 UTC (permalink / raw)
To: David Ahern
Cc: daniel, ast, netdev, David Ahern, Toke Høiland-Jørgensen
On Sun, Apr 12, 2020 at 07:32:04AM -0600, David Ahern wrote:
> From: David Ahern <dsahern@gmail.com>
>
> The commit mentioned in the Fixes tag reuses the local prog variable
> when looking up an expected_fd. The variable is not reset when fd < 0
> causing a detach with the expected_fd set to actually call
> dev_xdp_install for the existing program. The end result is that the
> detach does not happen.
>
> Fixes: 92234c8f15c8 ("xdp: Support specifying expected existing program when attaching XDP")
> Signed-off-by: David Ahern <dsahern@gmail.com>
> Cc: Toke Høiland-Jørgensen <toke@redhat.com>
Argh. Thanks for the fix.
Toke, please review.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH bpf] xdp: Reset prog in dev_change_xdp_fd when fd is negative
2020-04-12 13:32 [PATCH bpf] xdp: Reset prog in dev_change_xdp_fd when fd is negative David Ahern
2020-04-12 18:11 ` Jakub Kicinski
2020-04-13 22:08 ` Alexei Starovoitov
@ 2020-04-14 7:17 ` Toke Høiland-Jørgensen
2020-04-14 19:45 ` Daniel Borkmann
2 siblings, 1 reply; 5+ messages in thread
From: Toke Høiland-Jørgensen @ 2020-04-14 7:17 UTC (permalink / raw)
To: David Ahern, daniel, ast; +Cc: netdev, David Ahern
David Ahern <dsahern@kernel.org> writes:
> From: David Ahern <dsahern@gmail.com>
>
> The commit mentioned in the Fixes tag reuses the local prog variable
> when looking up an expected_fd. The variable is not reset when fd < 0
> causing a detach with the expected_fd set to actually call
> dev_xdp_install for the existing program. The end result is that the
> detach does not happen.
>
> Fixes: 92234c8f15c8 ("xdp: Support specifying expected existing program when attaching XDP")
> Signed-off-by: David Ahern <dsahern@gmail.com>
> Cc: Toke Høiland-Jørgensen <toke@redhat.com>
Ugh, my bad (obviously!). Thanks for the fix! I'll send an update to the
selftest to catch errors like this...
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH bpf] xdp: Reset prog in dev_change_xdp_fd when fd is negative
2020-04-14 7:17 ` Toke Høiland-Jørgensen
@ 2020-04-14 19:45 ` Daniel Borkmann
0 siblings, 0 replies; 5+ messages in thread
From: Daniel Borkmann @ 2020-04-14 19:45 UTC (permalink / raw)
To: Toke Høiland-Jørgensen, David Ahern, ast; +Cc: netdev, David Ahern
On 4/14/20 9:17 AM, Toke Høiland-Jørgensen wrote:
> David Ahern <dsahern@kernel.org> writes:
>
>> From: David Ahern <dsahern@gmail.com>
>>
>> The commit mentioned in the Fixes tag reuses the local prog variable
>> when looking up an expected_fd. The variable is not reset when fd < 0
>> causing a detach with the expected_fd set to actually call
>> dev_xdp_install for the existing program. The end result is that the
>> detach does not happen.
>>
>> Fixes: 92234c8f15c8 ("xdp: Support specifying expected existing program when attaching XDP")
>> Signed-off-by: David Ahern <dsahern@gmail.com>
>> Cc: Toke Høiland-Jørgensen <toke@redhat.com>
>
> Ugh, my bad (obviously!). Thanks for the fix! I'll send an update to the
> selftest to catch errors like this...
+1
> Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Applied, thanks!
^ permalink raw reply [flat|nested] 5+ messages in thread
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2020-04-12 13:32 [PATCH bpf] xdp: Reset prog in dev_change_xdp_fd when fd is negative David Ahern
2020-04-12 18:11 ` Jakub Kicinski
2020-04-13 22:08 ` Alexei Starovoitov
2020-04-14 7:17 ` Toke Høiland-Jørgensen
2020-04-14 19:45 ` Daniel Borkmann
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