eth: bnxt: return fail if interface is down in bnxt_queue_mem_alloc()

JIRA: https://issues.redhat.com/browse/RHEL-106550
CVE: CVE-2025-21974

commit ca2456e
Author: Taehee Yoo <[email protected]>
Date:   Sun Mar 9 13:42:13 2025 +0000

    eth: bnxt: return fail if interface is down in bnxt_queue_mem_alloc()

    The bnxt_queue_mem_alloc() is called to allocate new queue memory when
    a queue is restarted.
    It internally accesses rx buffer descriptor corresponding to the index.
    The rx buffer descriptor is allocated and set when the interface is up
    and it's freed when the interface is down.
    So, if queue is restarted if interface is down, kernel panic occurs.

    Splat looks like:
     BUG: unable to handle page fault for address: 000000000000b240
     #PF: supervisor read access in kernel mode
     #PF: error_code(0x0000) - not-present page
     PGD 0 P4D 0
     Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI
     CPU: 3 UID: 0 PID: 1563 Comm: ncdevmem2 Not tainted 6.14.0-rc2+ #9 844ddba6e7c459cafd0bf4db9a3198e
     Hardware name: ASUS System Product Name/PRIME Z690-P D4, BIOS 0603 11/01/2021
     RIP: 0010:bnxt_queue_mem_alloc+0x3f/0x4e0 [bnxt_en]
     Code: 41 54 4d 89 c4 4d 69 c0 c0 05 00 00 55 48 89 f5 53 48 89 fb 4c 8d b5 40 05 00 00 48 83 ec 15
     RSP: 0018:ffff9dcc83fef9e8 EFLAGS: 00010202
     RAX: ffffffffc0457720 RBX: ffff934ed8d40000 RCX: 0000000000000000
     RDX: 000000000000001f RSI: ffff934ea508f800 RDI: ffff934ea508f808
     RBP: ffff934ea508f800 R08: 000000000000b240 R09: ffff934e84f4b000
     R10: ffff9dcc83fefa30 R11: ffff934e84f4b000 R12: 000000000000001f
     R13: ffff934ed8d40ac0 R14: ffff934ea508fd40 R15: ffff934e84f4b000
     FS:  00007fa73888c740(0000) GS:ffff93559f780000(0000) knlGS:0000000000000000
     CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
     CR2: 000000000000b240 CR3: 0000000145a2e000 CR4: 00000000007506f0
     PKRU: 55555554
     Call Trace:
      <TASK>
      ? __die+0x20/0x70
      ? page_fault_oops+0x15a/0x460
      ? exc_page_fault+0x6e/0x180
      ? asm_exc_page_fault+0x22/0x30
      ? __pfx_bnxt_queue_mem_alloc+0x10/0x10 [bnxt_en 7f85e76f4d724ba07471d7e39d9e773aea6597b7]
      ? bnxt_queue_mem_alloc+0x3f/0x4e0 [bnxt_en 7f85e76f4d724ba07471d7e39d9e773aea6597b7]
      netdev_rx_queue_restart+0xc5/0x240
      net_devmem_bind_dmabuf_to_queue+0xf8/0x200
      netdev_nl_bind_rx_doit+0x3a7/0x450
      genl_family_rcv_msg_doit+0xd9/0x130
      genl_rcv_msg+0x184/0x2b0
      ? __pfx_netdev_nl_bind_rx_doit+0x10/0x10
      ? __pfx_genl_rcv_msg+0x10/0x10
      netlink_rcv_skb+0x54/0x100
      genl_rcv+0x24/0x40
    ...

    Reviewed-by: Somnath Kotur <[email protected]>
    Reviewed-by: Jakub Kicinski <[email protected]>
    Fixes: 2d694c2 ("bnxt_en: implement netdev_queue_mgmt_ops")
    Signed-off-by: Taehee Yoo <[email protected]>
    Reviewed-by: Mina Almasry <[email protected]>
    Link: https://patch.msgid.link/[email protected]
    Signed-off-by: Jakub Kicinski <[email protected]>

Signed-off-by: Michal Schmidt <[email protected]>

Author: michich

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -15581,6 +15581,9 @@ static int bnxt_queue_mem_alloc(struct net_device *dev, void *qmem, int idx)
 	struct bnxt_ring_struct *ring;
 	int rc;
 
+	if (!bp->rx_ring)
+		return -ENETDOWN;
+
 	rxr = &bp->rx_ring[idx];
 	clone = qmem;
 	memcpy(clone, rxr, sizeof(*rxr));