CVE-2024-47734 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
bonding: Fix unnecessary warnings and logs from bond_xdp_get_xmit_slave()
syzbot reported a WARNING in bond_xdp_get_xmit_slave. To reproduce this[1], one bond device (bond1) has xdpdrv, which increases
bpf_master_redirect_enabled_key. Another bond device (bond0) which is unsupported by XDP but its slave (veth3) has xdpgeneric that returns XDP_TX. This triggers WARN_ON_ONCE() from the xdp_master_redirect(). To reduce unnecessary warnings and improve log management, we need to delete the WARN_ON_ONCE() and add ratelimit to the netdev_err().
[1] Steps to reproduce:
# Needs tx_xdp with return XDP_TX; ip l add veth0 type veth peer veth1 ip l add veth3 type veth peer veth4 ip l add bond0 type bond mode 6 # BOND_MODE_ALB, unsupported by XDP ip l add bond1 type bond # BOND_MODE_ROUNDROBIN by default ip l set veth0 master bond1 ip l set bond1 up # Increases bpf_master_redirect_enabled_key ip l set dev bond1 xdpdrv object tx_xdp.o section xdp_tx ip l set veth3 master bond0 ip l set bond0 up ip l set veth4 up # Triggers WARN_ON_ONCE() from the xdp_master_redirect() ip l set veth3 xdpgeneric object tx_xdp.o section xdp_tx
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Analysis
by VulDB Data Team • 01/19/2026
The vulnerability described in CVE-2024-47734 resides within the Linux kernel's bonding driver implementation, specifically in the bond_xdp_get_xmit_slave() function. This issue manifests as unnecessary warning messages that clutter system logs and potentially impact system performance through excessive logging. The problem occurs in environments where multiple bond devices coexist with different XDP (eXpress Data Path) configurations, creating a scenario where the kernel's XDP master redirect functionality encounters unexpected conditions that trigger warning states.
The technical flaw stems from the improper handling of XDP master redirect operations when multiple bond devices exist with varying XDP support capabilities. When one bond device (bond1) utilizes xdpdrv which increments the bpf_master_redirect_enabled_key counter, and another bond device (bond0) contains a slave interface (veth3) that supports xdpgeneric with XDP_TX return values, the system triggers a WARN_ON_ONCE() condition within the xdp_master_redirect() function. This occurs because the kernel's internal logic does not properly account for the scenario where XDP master redirect functionality is enabled but the slave interface configuration creates an inconsistent state that should not necessarily warrant a warning.
The operational impact of this vulnerability involves excessive logging that can overwhelm system administrators and potentially mask genuine issues within the network stack. The warnings generated are not indicative of actual system failures but rather represent a design oversight in how the kernel handles edge cases involving multiple XDP-enabled interfaces within bonding configurations. This can lead to log management challenges and make it more difficult to identify real security or performance issues that require attention.
The resolution strategy involves removing the WARN_ON_ONCE() macro from the xdp_master_redirect() function and implementing ratelimiting for the netdev_err() calls. This approach follows security best practices by preventing log flooding while maintaining the ability to capture genuine error conditions. The fix aligns with the principle of avoiding false positive warnings that can degrade system monitoring effectiveness. The implementation addresses the underlying issue by ensuring that the kernel's logging behavior remains appropriate for legitimate error conditions while eliminating noise from expected operational scenarios.
This vulnerability demonstrates the complexity of modern network stack implementations where multiple technologies like bonding and XDP must interoperate seamlessly. The fix reflects the importance of proper error handling and logging in kernel space code, where inappropriate warnings can create operational overhead and reduce system maintainability. The solution maintains system stability while improving the quality of diagnostic information available to administrators, which is consistent with security practices that emphasize the importance of meaningful logging over excessive noise generation. The issue relates to CWE-704 in the Common Weakness Enumeration catalog, which covers improper error handling in kernel modules, and aligns with ATT&CK technique T1562.006 for privilege escalation through kernel vulnerabilities, though this particular issue is more focused on operational impact than direct security compromise.