fkie_cve-2023-53489
Vulnerability from fkie_nvd
Published
2025-10-01 12:15
Modified
2025-10-02 19:12
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: tcp/udp: Fix memleaks of sk and zerocopy skbs with TX timestamp. syzkaller reported [0] memory leaks of an UDP socket and ZEROCOPY skbs. We can reproduce the problem with these sequences: sk = socket(AF_INET, SOCK_DGRAM, 0) sk.setsockopt(SOL_SOCKET, SO_TIMESTAMPING, SOF_TIMESTAMPING_TX_SOFTWARE) sk.setsockopt(SOL_SOCKET, SO_ZEROCOPY, 1) sk.sendto(b'', MSG_ZEROCOPY, ('127.0.0.1', 53)) sk.close() sendmsg() calls msg_zerocopy_alloc(), which allocates a skb, sets skb->cb->ubuf.refcnt to 1, and calls sock_hold(). Here, struct ubuf_info_msgzc indirectly holds a refcnt of the socket. When the skb is sent, __skb_tstamp_tx() clones it and puts the clone into the socket's error queue with the TX timestamp. When the original skb is received locally, skb_copy_ubufs() calls skb_unclone(), and pskb_expand_head() increments skb->cb->ubuf.refcnt. This additional count is decremented while freeing the skb, but struct ubuf_info_msgzc still has a refcnt, so __msg_zerocopy_callback() is not called. The last refcnt is not released unless we retrieve the TX timestamped skb by recvmsg(). Since we clear the error queue in inet_sock_destruct() after the socket's refcnt reaches 0, there is a circular dependency. If we close() the socket holding such skbs, we never call sock_put() and leak the count, sk, and skb. TCP has the same problem, and commit e0c8bccd40fc ("net: stream: purge sk_error_queue in sk_stream_kill_queues()") tried to fix it by calling skb_queue_purge() during close(). However, there is a small chance that skb queued in a qdisc or device could be put into the error queue after the skb_queue_purge() call. In __skb_tstamp_tx(), the cloned skb should not have a reference to the ubuf to remove the circular dependency, but skb_clone() does not call skb_copy_ubufs() for zerocopy skb. So, we need to call skb_orphan_frags_rx() for the cloned skb to call skb_copy_ubufs(). [0]: BUG: memory leak unreferenced object 0xffff88800c6d2d00 (size 1152): comm "syz-executor392", pid 264, jiffies 4294785440 (age 13.044s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 cd af e8 81 00 00 00 00 ................ 02 00 07 40 00 00 00 00 00 00 00 00 00 00 00 00 ...@............ backtrace: [<0000000055636812>] sk_prot_alloc+0x64/0x2a0 net/core/sock.c:2024 [<0000000054d77b7a>] sk_alloc+0x3b/0x800 net/core/sock.c:2083 [<0000000066f3c7e0>] inet_create net/ipv4/af_inet.c:319 [inline] [<0000000066f3c7e0>] inet_create+0x31e/0xe40 net/ipv4/af_inet.c:245 [<000000009b83af97>] __sock_create+0x2ab/0x550 net/socket.c:1515 [<00000000b9b11231>] sock_create net/socket.c:1566 [inline] [<00000000b9b11231>] __sys_socket_create net/socket.c:1603 [inline] [<00000000b9b11231>] __sys_socket_create net/socket.c:1588 [inline] [<00000000b9b11231>] __sys_socket+0x138/0x250 net/socket.c:1636 [<000000004fb45142>] __do_sys_socket net/socket.c:1649 [inline] [<000000004fb45142>] __se_sys_socket net/socket.c:1647 [inline] [<000000004fb45142>] __x64_sys_socket+0x73/0xb0 net/socket.c:1647 [<0000000066999e0e>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<0000000066999e0e>] do_syscall_64+0x38/0x90 arch/x86/entry/common.c:80 [<0000000017f238c1>] entry_SYSCALL_64_after_hwframe+0x63/0xcd BUG: memory leak unreferenced object 0xffff888017633a00 (size 240): comm "syz-executor392", pid 264, jiffies 4294785440 (age 13.044s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 2d 6d 0c 80 88 ff ff .........-m..... backtrace: [<000000002b1c4368>] __alloc_skb+0x229/0x320 net/core/skbuff.c:497 [<00000000143579a6>] alloc_skb include/linux/skbuff.h:1265 [inline] [<00000000143579a6>] sock_omalloc+0xaa/0x190 net/core/sock.c:2596 [<00000000be626478>] msg_zerocopy_alloc net/core/skbuff.c:1294 [inline] [<00000000be626478>] ---truncated---
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1f69c086b20e27763af28145981435423f088268
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/230a5ed7d813fb516de81d23f09d7506753e41e9
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/281072fb2a7294cde7acbf5375b879f40a8001b7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/30290f210ba7426ff7592fe2eb4114b1b5bad219
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/426384dd4980040651536fef5feac4dcc4d7ee4e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/43e4197dd5f6b474a8b16f8b6a42cd45cf4f9d1a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/50749f2dd6854a41830996ad302aef2ffaf011d8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/602fa8af44fd55a58f9e94eb673e8adad2c6cc46
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/cb52e7f24c1d01a536a847dff0d1d95889cc3b5c
Impacted products
Vendor Product Version


To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp/udp: Fix memleaks of sk and zerocopy skbs with TX timestamp.\n\nsyzkaller reported [0] memory leaks of an UDP socket and ZEROCOPY\nskbs.  We can reproduce the problem with these sequences:\n\n  sk = socket(AF_INET, SOCK_DGRAM, 0)\n  sk.setsockopt(SOL_SOCKET, SO_TIMESTAMPING, SOF_TIMESTAMPING_TX_SOFTWARE)\n  sk.setsockopt(SOL_SOCKET, SO_ZEROCOPY, 1)\n  sk.sendto(b\u0027\u0027, MSG_ZEROCOPY, (\u0027127.0.0.1\u0027, 53))\n  sk.close()\n\nsendmsg() calls msg_zerocopy_alloc(), which allocates a skb, sets\nskb-\u003ecb-\u003eubuf.refcnt to 1, and calls sock_hold().  Here, struct\nubuf_info_msgzc indirectly holds a refcnt of the socket.  When the\nskb is sent, __skb_tstamp_tx() clones it and puts the clone into\nthe socket\u0027s error queue with the TX timestamp.\n\nWhen the original skb is received locally, skb_copy_ubufs() calls\nskb_unclone(), and pskb_expand_head() increments skb-\u003ecb-\u003eubuf.refcnt.\nThis additional count is decremented while freeing the skb, but struct\nubuf_info_msgzc still has a refcnt, so __msg_zerocopy_callback() is\nnot called.\n\nThe last refcnt is not released unless we retrieve the TX timestamped\nskb by recvmsg().  Since we clear the error queue in inet_sock_destruct()\nafter the socket\u0027s refcnt reaches 0, there is a circular dependency.\nIf we close() the socket holding such skbs, we never call sock_put()\nand leak the count, sk, and skb.\n\nTCP has the same problem, and commit e0c8bccd40fc (\"net: stream:\npurge sk_error_queue in sk_stream_kill_queues()\") tried to fix it\nby calling skb_queue_purge() during close().  However, there is a\nsmall chance that skb queued in a qdisc or device could be put\ninto the error queue after the skb_queue_purge() call.\n\nIn __skb_tstamp_tx(), the cloned skb should not have a reference\nto the ubuf to remove the circular dependency, but skb_clone() does\nnot call skb_copy_ubufs() for zerocopy skb.  So, we need to call\nskb_orphan_frags_rx() for the cloned skb to call skb_copy_ubufs().\n\n[0]:\nBUG: memory leak\nunreferenced object 0xffff88800c6d2d00 (size 1152):\n  comm \"syz-executor392\", pid 264, jiffies 4294785440 (age 13.044s)\n  hex dump (first 32 bytes):\n    00 00 00 00 00 00 00 00 cd af e8 81 00 00 00 00  ................\n    02 00 07 40 00 00 00 00 00 00 00 00 00 00 00 00  ...@............\n  backtrace:\n    [\u003c0000000055636812\u003e] sk_prot_alloc+0x64/0x2a0 net/core/sock.c:2024\n    [\u003c0000000054d77b7a\u003e] sk_alloc+0x3b/0x800 net/core/sock.c:2083\n    [\u003c0000000066f3c7e0\u003e] inet_create net/ipv4/af_inet.c:319 [inline]\n    [\u003c0000000066f3c7e0\u003e] inet_create+0x31e/0xe40 net/ipv4/af_inet.c:245\n    [\u003c000000009b83af97\u003e] __sock_create+0x2ab/0x550 net/socket.c:1515\n    [\u003c00000000b9b11231\u003e] sock_create net/socket.c:1566 [inline]\n    [\u003c00000000b9b11231\u003e] __sys_socket_create net/socket.c:1603 [inline]\n    [\u003c00000000b9b11231\u003e] __sys_socket_create net/socket.c:1588 [inline]\n    [\u003c00000000b9b11231\u003e] __sys_socket+0x138/0x250 net/socket.c:1636\n    [\u003c000000004fb45142\u003e] __do_sys_socket net/socket.c:1649 [inline]\n    [\u003c000000004fb45142\u003e] __se_sys_socket net/socket.c:1647 [inline]\n    [\u003c000000004fb45142\u003e] __x64_sys_socket+0x73/0xb0 net/socket.c:1647\n    [\u003c0000000066999e0e\u003e] do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n    [\u003c0000000066999e0e\u003e] do_syscall_64+0x38/0x90 arch/x86/entry/common.c:80\n    [\u003c0000000017f238c1\u003e] entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nBUG: memory leak\nunreferenced object 0xffff888017633a00 (size 240):\n  comm \"syz-executor392\", pid 264, jiffies 4294785440 (age 13.044s)\n  hex dump (first 32 bytes):\n    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................\n    00 00 00 00 00 00 00 00 00 2d 6d 0c 80 88 ff ff  .........-m.....\n  backtrace:\n    [\u003c000000002b1c4368\u003e] __alloc_skb+0x229/0x320 net/core/skbuff.c:497\n    [\u003c00000000143579a6\u003e] alloc_skb include/linux/skbuff.h:1265 [inline]\n    [\u003c00000000143579a6\u003e] sock_omalloc+0xaa/0x190 net/core/sock.c:2596\n    [\u003c00000000be626478\u003e] msg_zerocopy_alloc net/core/skbuff.c:1294 [inline]\n    [\u003c00000000be626478\u003e]\n---truncated---"
    }
  ],
  "id": "CVE-2023-53489",
  "lastModified": "2025-10-02T19:12:17.160",
  "metrics": {},
  "published": "2025-10-01T12:15:51.950",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1f69c086b20e27763af28145981435423f088268"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/230a5ed7d813fb516de81d23f09d7506753e41e9"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/281072fb2a7294cde7acbf5375b879f40a8001b7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/30290f210ba7426ff7592fe2eb4114b1b5bad219"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/426384dd4980040651536fef5feac4dcc4d7ee4e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/43e4197dd5f6b474a8b16f8b6a42cd45cf4f9d1a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/50749f2dd6854a41830996ad302aef2ffaf011d8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/602fa8af44fd55a58f9e94eb673e8adad2c6cc46"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cb52e7f24c1d01a536a847dff0d1d95889cc3b5c"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.