Skip to content
CVE PROGRAM SOURCE RECORD9.8 Critical

CVE-2025-39703

net, hsr: reject HSR frame if skb can't hold tag

Read JSON ↗CVE.org ↗
Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: net, hsr: reject HSR frame if skb can't hold tag Receiving HSR frame with insufficient space to hold HSR tag in the skb can result in a crash (kernel BUG): [ 45.390915] skbuff: skb_under_panic: text:ffffffff86f32cac len:26 put:14 head:ffff888042418000 data:ffff888042417ff4 tail:0xe end:0x180 dev:bridge_slave_1 [ 45.392559] ------------[ cut here ]------------ [ 45.392912] kernel BUG at net/core/skbuff.c:211! [ 45.393276] Oops: invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI [ 45.393809] CPU: 1 UID: 0 PID: 2496 Comm: reproducer Not tainted 6.15.0 #12 PREEMPT(undef) [ 45.394433] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 45.395273] RIP: 0010:skb_panic+0x15b/0x1d0 <snip registers, remove unreliable trace> [ 45.402911] Call Trace: [ 45.403105] <IRQ> [ 45.404470] skb_push+0xcd/0xf0 [ 45.404726] br_dev_queue_push_xmit+0x7c/0x6c0 [ 45.406513] br_forward_finish+0x128/0x260 [ 45.408483] __br_forward+0x42d/0x590 [ 45.409464] maybe_deliver+0x2eb/0x420 [ 45.409763] br_flood+0x174/0x4a0 [ 45.410030] br_handle_frame_finish+0xc7c/0x1bc0 [ 45.411618] br_handle_frame+0xac3/0x1230 [ 45.413674] __netif_receive_skb_core.constprop.0+0x808/0x3df0 [ 45.422966] __netif_receive_skb_one_core+0xb4/0x1f0 [ 45.424478] __netif_receive_skb+0x22/0x170 [ 45.424806] process_backlog+0x242/0x6d0 [ 45.425116] __napi_poll+0xbb/0x630 [ 45.425394] net_rx_action+0x4d1/0xcc0 [ 45.427613] handle_softirqs+0x1a4/0x580 [ 45.427926] do_softirq+0x74/0x90 [ 45.428196] </IRQ> This issue was found by syzkaller. The panic happens in br_dev_queue_push_xmit() once it receives a corrupted skb with ETH header already pushed in linear data. When it attempts the skb_push() call, there's not enough headroom and skb_push() panics. The corrupted skb is put on the queue by HSR layer, which makes a sequence of unintended transformations when it receives a specific corrupted HSR frame (with incomplete TAG). Fix it by dropping and consuming frames that are not long enough to contain both ethernet and hsr headers. Alternative fix would be to check for enough headroom before skb_push() in br_dev_queue_push_xmit(). In the reproducer, this is injected via AF_PACKET, but I don't easily see why it couldn't be sent over the wire from adjacent network. Further Details: In the reproducer, the following network interface chain is set up: ┌────────────────┐ ┌────────────────┐ │ veth0_to_hsr ├───┤ hsr_slave0 ┼───┐ └────────────────┘ └────────────────┘ │ │ ┌──────┐ ├─┤ hsr0 ├───┐ │ └──────┘ │ ┌────────────────┐ ┌────────────────┐ │ │┌────────┐ │ veth1_to_hsr ┼───┤ hsr_slave1 ├───┘ └┤ │ └────────────────┘ └────────────────┘ ┌┼ bridge │ ││ │ │└────────┘ │ ┌───────┐ │ │ ... ├──────┘ └───────┘ To trigger the events leading up to crash, reproducer sends a corrupted HSR fr ---truncated---

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • f6442ee08fe66c8e45c4f246531a2aaf4f17a7a7 to < 8d9bc4a375a1ba05f7dfa0407de8e510ab9bd14daffected
  • 48b491a5cc74333c4a6a82fe21cea42c055a3b0b to < 3ae272ab523dd6bdc26e879027ed79feac9dd1b3affected
  • 48b491a5cc74333c4a6a82fe21cea42c055a3b0b to < b640188b8a6690e685939053c7efdbc7818b5f4eaffected
  • 48b491a5cc74333c4a6a82fe21cea42c055a3b0b to < b117c41b00902c1a7e24347c405cb82504aeae0baffected
  • 48b491a5cc74333c4a6a82fe21cea42c055a3b0b to < acd69b597bd3f76d3b3d322b84082226c00eeaa4affected
  • 48b491a5cc74333c4a6a82fe21cea42c055a3b0b to < 61009439e4bd8d74e705ee15940760321be91d8aaffected
  • 48b491a5cc74333c4a6a82fe21cea42c055a3b0b to < 7af76e9d18a9fd6f8611b3313c86c190f9b6a5a7affected
  • 4ffd1d4a6b306ff69cbe412d2c54d2dd349ff436affected
  • 5.10.42 to < 5.10.241affected
  • 5.12.9 to < 5.13affected

Linux Linux

Default version status: affected

  • 5.13affected
  • 0 to < 5.13unaffected
  • 5.10.241 to ≤ 5.10.*unaffected
  • 5.15.190 to ≤ 5.15.*unaffected
  • 6.1.149 to ≤ 6.1.*unaffected
  • 6.6.103 to ≤ 6.6.*unaffected
  • 6.12.44 to ≤ 6.12.*unaffected
  • 6.16.4 to ≤ 6.16.*unaffected
  • 6.17 to ≤ *unaffected

References