fkie_cve-2025-38525
Vulnerability from fkie_nvd
Published
2025-08-16 12:15
Modified
2025-08-18 20:16
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix irq-disabled in local_bh_enable() The rxrpc_assess_MTU_size() function calls down into the IP layer to find out the MTU size for a route. When accepting an incoming call, this is called from rxrpc_new_incoming_call() which holds interrupts disabled across the code that calls down to it. Unfortunately, the IP layer uses local_bh_enable() which, config dependent, throws a warning if IRQs are enabled: WARNING: CPU: 1 PID: 5544 at kernel/softirq.c:387 __local_bh_enable_ip+0x43/0xd0 ... RIP: 0010:__local_bh_enable_ip+0x43/0xd0 ... Call Trace: <TASK> rt_cache_route+0x7e/0xa0 rt_set_nexthop.isra.0+0x3b3/0x3f0 __mkroute_output+0x43a/0x460 ip_route_output_key_hash+0xf7/0x140 ip_route_output_flow+0x1b/0x90 rxrpc_assess_MTU_size.isra.0+0x2a0/0x590 rxrpc_new_incoming_peer+0x46/0x120 rxrpc_alloc_incoming_call+0x1b1/0x400 rxrpc_new_incoming_call+0x1da/0x5e0 rxrpc_input_packet+0x827/0x900 rxrpc_io_thread+0x403/0xb60 kthread+0x2f7/0x310 ret_from_fork+0x2a/0x230 ret_from_fork_asm+0x1a/0x30 ... hardirqs last enabled at (23): _raw_spin_unlock_irq+0x24/0x50 hardirqs last disabled at (24): _raw_read_lock_irq+0x17/0x70 softirqs last enabled at (0): copy_process+0xc61/0x2730 softirqs last disabled at (25): rt_add_uncached_list+0x3c/0x90 Fix this by moving the call to rxrpc_assess_MTU_size() out of rxrpc_init_peer() and further up the stack where it can be done without interrupts disabled. It shouldn't be a problem for rxrpc_new_incoming_call() to do it after the locks are dropped as pmtud is going to be performed by the I/O thread - and we're in the I/O thread at this point.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2029f21f10dedb88c0f86abffcf8d6c21dcf6040
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e4d2878369d590bf8455e3678a644e503172eafa
Impacted products
Vendor Product Version


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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix irq-disabled in local_bh_enable()\n\nThe rxrpc_assess_MTU_size() function calls down into the IP layer to find\nout the MTU size for a route.  When accepting an incoming call, this is\ncalled from rxrpc_new_incoming_call() which holds interrupts disabled\nacross the code that calls down to it.  Unfortunately, the IP layer uses\nlocal_bh_enable() which, config dependent, throws a warning if IRQs are\nenabled:\n\nWARNING: CPU: 1 PID: 5544 at kernel/softirq.c:387 __local_bh_enable_ip+0x43/0xd0\n...\nRIP: 0010:__local_bh_enable_ip+0x43/0xd0\n...\nCall Trace:\n \u003cTASK\u003e\n rt_cache_route+0x7e/0xa0\n rt_set_nexthop.isra.0+0x3b3/0x3f0\n __mkroute_output+0x43a/0x460\n ip_route_output_key_hash+0xf7/0x140\n ip_route_output_flow+0x1b/0x90\n rxrpc_assess_MTU_size.isra.0+0x2a0/0x590\n rxrpc_new_incoming_peer+0x46/0x120\n rxrpc_alloc_incoming_call+0x1b1/0x400\n rxrpc_new_incoming_call+0x1da/0x5e0\n rxrpc_input_packet+0x827/0x900\n rxrpc_io_thread+0x403/0xb60\n kthread+0x2f7/0x310\n ret_from_fork+0x2a/0x230\n ret_from_fork_asm+0x1a/0x30\n...\nhardirqs last  enabled at (23): _raw_spin_unlock_irq+0x24/0x50\nhardirqs last disabled at (24): _raw_read_lock_irq+0x17/0x70\nsoftirqs last  enabled at (0): copy_process+0xc61/0x2730\nsoftirqs last disabled at (25): rt_add_uncached_list+0x3c/0x90\n\nFix this by moving the call to rxrpc_assess_MTU_size() out of\nrxrpc_init_peer() and further up the stack where it can be done without\ninterrupts disabled.\n\nIt shouldn\u0027t be a problem for rxrpc_new_incoming_call() to do it after the\nlocks are dropped as pmtud is going to be performed by the I/O thread - and\nwe\u0027re in the I/O thread at this point."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: rxrpc: Se corrige la inhabilitaci\u00f3n de irq en local_bh_enable(). La funci\u00f3n rxrpc_assess_MTU_size() realiza una llamada a la capa IP para determinar el tama\u00f1o de MTU de una ruta. Al aceptar una llamada entrante, se realiza una llamada desde rxrpc_new_incoming_call(), que mantiene las interrupciones deshabilitadas en el c\u00f3digo que la realiza. Desafortunadamente, la capa IP usa local_bh_enable() que, dependiendo de la configuraci\u00f3n, lanza una advertencia si las IRQ est\u00e1n habilitadas: WARNING: CPU: 1 PID: 5544 at kernel/softirq.c:387 __local_bh_enable_ip+0x43/0xd0 ... RIP: 0010:__local_bh_enable_ip+0x43/0xd0 ... Call Trace:  rt_cache_route+0x7e/0xa0 rt_set_nexthop.isra.0+0x3b3/0x3f0 __mkroute_output+0x43a/0x460 ip_route_output_key_hash+0xf7/0x140 ip_route_output_flow+0x1b/0x90 rxrpc_assess_MTU_size.isra.0+0x2a0/0x590 rxrpc_new_incoming_peer+0x46/0x120 rxrpc_alloc_incoming_call+0x1b1/0x400 rxrpc_new_incoming_call+0x1da/0x5e0 rxrpc_input_packet+0x827/0x900 rxrpc_io_thread+0x403/0xb60 kthread+0x2f7/0x310 ret_from_fork+0x2a/0x230 ret_from_fork_asm+0x1a/0x30 ... hardirqs last enabled at (23): _raw_spin_unlock_irq+0x24/0x50 hardirqs last disabled at (24): _raw_read_lock_irq+0x17/0x70 softirqs last enabled at (0): copy_process+0xc61/0x2730 softirqs last disabled at (25): rt_add_uncached_list+0x3c/0x90. Para solucionar esto, mueva la llamada a rxrpc_assess_MTU_size() fuera de rxrpc_init_peer() y a una posici\u00f3n m\u00e1s alta en la pila, donde pueda realizarse sin interrupciones deshabilitadas. No deber\u00eda ser un problema para rxrpc_new_incoming_call() realizarlo despu\u00e9s de que se eliminen los bloqueos, ya que pmtud lo realizar\u00e1 el hilo de E/S (y en este momento estamos en el hilo de E/S)."
    }
  ],
  "id": "CVE-2025-38525",
  "lastModified": "2025-08-18T20:16:28.750",
  "metrics": {},
  "published": "2025-08-16T12:15:27.933",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2029f21f10dedb88c0f86abffcf8d6c21dcf6040"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e4d2878369d590bf8455e3678a644e503172eafa"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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