lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date:   Sun, 12 Apr 2020 07:32:04 -0600
From:   David Ahern <>
Cc:, David Ahern <>,
        Toke Høiland-Jørgensen <>
Subject: [PATCH bpf] xdp: Reset prog in dev_change_xdp_fd when fd is negative

From: David Ahern <>

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 <>
Cc: Toke Høiland-Jørgensen <>
 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);

Powered by blists - more mailing lists