CVE-2025-38224 Information

Jul 05, 2025 cve

Description

In the Linux kernel the following vulnerability has been resolved:

can: kvaser_pciefd: refine error prone echo_skb_max handling logic

echo_skb_max should define the supported upper limit of echo_skb[] allocated inside the netdevice’s priv. The corresponding size value provided by this driver to alloc_candev() is KVASER_PCIEFD_CAN_TX_MAX_COUNT which is 17.

But later echo_skb_max is rounded up to the nearest power of two (for the max case that would be 32) and the tx/ack indices calculated further during tx/rx may exceed the upper array boundary. Kasan reported this for the ack case inside kvaser_pciefd_handle_ack_packet() though the xmit function has actually caught the same thing earlier.

BUG: KASAN: slab-out-of-bounds in kvaser_pciefd_handle_ack_packet+0x2d7/0x92a drivers/net/can/kvaser_pciefd.c:1528 Read of size 8 at addr ffff888105e4f078 by task swapper/4/0

CPU: 4 UID: 0 PID: 0 Comm: swapper/4 Not tainted 6.15.0 12 PREEMPT(voluntary) Call Trace: dump_stack_lvl lib/dump_stack.c:122 print_report mm/kasan/report.c:521 kasan_report mm/kasan/report.c:634 kvaser_pciefd_handle_ack_packet drivers/net/can/kvaser_pciefd.c:1528 kvaser_pciefd_read_packet drivers/net/can/kvaser_pciefd.c:1605 kvaser_pciefd_read_buffer drivers/net/can/kvaser_pciefd.c:1656 kvaser_pciefd_receive_irq drivers/net/can/kvaser_pciefd.c:1684 kvaser_pciefd_irq_handler drivers/net/can/kvaser_pciefd.c:1733 __handle_irq_event_percpu kernel/irq/handle.c:158 handle_irq_event kernel/irq/handle.c:210 handle_edge_irq kernel/irq/chip.c:833 __common_interrupt arch/x86/kernel/irq.c:296 common_interrupt arch/x86/kernel/irq.c:286

Tx max count definitely matters for kvaser_pciefd_tx_avail() but for seq numbers’ generation that’s not the case - we’re free to calculate them as would be more convenient not taking tx max count into account. The only downside is that the size of echo_skb[] should correspond to the max seq number (not tx max count) so in some situations a bit more memory would be consumed than could be.

Thus make the size of the underlying echo_skb[] sufficient for the rounded max tx value.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Reference

https://git.kernel.org/stable/c/54ec8b08216f3be2cc98b33633d3c8ea79749895 https://git.kernel.org/stable/c/a6550c9aa11e2f57f9cdaa6249cdd44d446be874 https://git.kernel.org/stable/c/d8a054b6e6824a8b52c3977ebd38c9583a63efac

CNNVD-202507-434 (Published: 2025-07-04)

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