ghsa-rpv2-375w-83vr
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
inet: fully convert sk->sk_rx_dst to RCU rules
syzbot reported various issues around early demux, one being included in this changelog [1]
sk->sk_rx_dst is using RCU protection without clearly documenting it.
And following sequences in tcp_v4_do_rcv()/tcp_v6_do_rcv() are not following standard RCU rules.
[a] dst_release(dst); [b] sk->sk_rx_dst = NULL;
They look wrong because a delete operation of RCU protected pointer is supposed to clear the pointer before the call_rcu()/synchronize_rcu() guarding actual memory freeing.
In some cases indeed, dst could be freed before [b] is done.
We could cheat by clearing sk_rx_dst before calling dst_release(), but this seems the right time to stick to standard RCU annotations and debugging facilities.
[1] BUG: KASAN: use-after-free in dst_check include/net/dst.h:470 [inline] BUG: KASAN: use-after-free in tcp_v4_early_demux+0x95b/0x960 net/ipv4/tcp_ipv4.c:1792 Read of size 2 at addr ffff88807f1cb73a by task syz-executor.5/9204
CPU: 0 PID: 9204 Comm: syz-executor.5 Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
Allocated by task 13: kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:259 [inline] slab_post_alloc_hook mm/slab.h:519 [inline] slab_alloc_node mm/slub.c:3234 [inline] slab_alloc mm/slub.c:3242 [inline] kmem_cache_alloc+0x202/0x3a0 mm/slub.c:3247 dst_alloc+0x146/0x1f0 net/core/dst.c:92 rt_dst_alloc+0x73/0x430 net/ipv4/route.c:1613 ip_route_input_slow+0x1817/0x3a20 net/ipv4/route.c:234 ---truncated---
{
"affected": [],
"aliases": [
"CVE-2021-47103"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-03-04T18:15:08Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ninet: fully convert sk-\u003esk_rx_dst to RCU rules\n\nsyzbot reported various issues around early demux,\none being included in this changelog [1]\n\nsk-\u003esk_rx_dst is using RCU protection without clearly\ndocumenting it.\n\nAnd following sequences in tcp_v4_do_rcv()/tcp_v6_do_rcv()\nare not following standard RCU rules.\n\n[a] dst_release(dst);\n[b] sk-\u003esk_rx_dst = NULL;\n\nThey look wrong because a delete operation of RCU protected\npointer is supposed to clear the pointer before\nthe call_rcu()/synchronize_rcu() guarding actual memory freeing.\n\nIn some cases indeed, dst could be freed before [b] is done.\n\nWe could cheat by clearing sk_rx_dst before calling\ndst_release(), but this seems the right time to stick\nto standard RCU annotations and debugging facilities.\n\n[1]\nBUG: KASAN: use-after-free in dst_check include/net/dst.h:470 [inline]\nBUG: KASAN: use-after-free in tcp_v4_early_demux+0x95b/0x960 net/ipv4/tcp_ipv4.c:1792\nRead of size 2 at addr ffff88807f1cb73a by task syz-executor.5/9204\n\nCPU: 0 PID: 9204 Comm: syz-executor.5 Not tainted 5.16.0-rc5-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011\nCall Trace:\n \u003cTASK\u003e\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106\n print_address_description.constprop.0.cold+0x8d/0x320 mm/kasan/report.c:247\n __kasan_report mm/kasan/report.c:433 [inline]\n kasan_report.cold+0x83/0xdf mm/kasan/report.c:450\n dst_check include/net/dst.h:470 [inline]\n tcp_v4_early_demux+0x95b/0x960 net/ipv4/tcp_ipv4.c:1792\n ip_rcv_finish_core.constprop.0+0x15de/0x1e80 net/ipv4/ip_input.c:340\n ip_list_rcv_finish.constprop.0+0x1b2/0x6e0 net/ipv4/ip_input.c:583\n ip_sublist_rcv net/ipv4/ip_input.c:609 [inline]\n ip_list_rcv+0x34e/0x490 net/ipv4/ip_input.c:644\n __netif_receive_skb_list_ptype net/core/dev.c:5508 [inline]\n __netif_receive_skb_list_core+0x549/0x8e0 net/core/dev.c:5556\n __netif_receive_skb_list net/core/dev.c:5608 [inline]\n netif_receive_skb_list_internal+0x75e/0xd80 net/core/dev.c:5699\n gro_normal_list net/core/dev.c:5853 [inline]\n gro_normal_list net/core/dev.c:5849 [inline]\n napi_complete_done+0x1f1/0x880 net/core/dev.c:6590\n virtqueue_napi_complete drivers/net/virtio_net.c:339 [inline]\n virtnet_poll+0xca2/0x11b0 drivers/net/virtio_net.c:1557\n __napi_poll+0xaf/0x440 net/core/dev.c:7023\n napi_poll net/core/dev.c:7090 [inline]\n net_rx_action+0x801/0xb40 net/core/dev.c:7177\n __do_softirq+0x29b/0x9c2 kernel/softirq.c:558\n invoke_softirq kernel/softirq.c:432 [inline]\n __irq_exit_rcu+0x123/0x180 kernel/softirq.c:637\n irq_exit_rcu+0x5/0x20 kernel/softirq.c:649\n common_interrupt+0x52/0xc0 arch/x86/kernel/irq.c:240\n asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:629\nRIP: 0033:0x7f5e972bfd57\nCode: 39 d1 73 14 0f 1f 80 00 00 00 00 48 8b 50 f8 48 83 e8 08 48 39 ca 77 f3 48 39 c3 73 3e 48 89 13 48 8b 50 f8 48 89 38 49 8b 0e \u003c48\u003e 8b 3e 48 83 c3 08 48 83 c6 08 eb bc 48 39 d1 72 9e 48 39 d0 73\nRSP: 002b:00007fff8a413210 EFLAGS: 00000283\nRAX: 00007f5e97108990 RBX: 00007f5e97108338 RCX: ffffffff81d3aa45\nRDX: ffffffff81d3aa45 RSI: 00007f5e97108340 RDI: ffffffff81d3aa45\nRBP: 00007f5e97107eb8 R08: 00007f5e97108d88 R09: 0000000093c2e8d9\nR10: 0000000000000000 R11: 0000000000000000 R12: 00007f5e97107eb0\nR13: 00007f5e97108338 R14: 00007f5e97107ea8 R15: 0000000000000019\n \u003c/TASK\u003e\n\nAllocated by task 13:\n kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38\n kasan_set_track mm/kasan/common.c:46 [inline]\n set_alloc_info mm/kasan/common.c:434 [inline]\n __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:467\n kasan_slab_alloc include/linux/kasan.h:259 [inline]\n slab_post_alloc_hook mm/slab.h:519 [inline]\n slab_alloc_node mm/slub.c:3234 [inline]\n slab_alloc mm/slub.c:3242 [inline]\n kmem_cache_alloc+0x202/0x3a0 mm/slub.c:3247\n dst_alloc+0x146/0x1f0 net/core/dst.c:92\n rt_dst_alloc+0x73/0x430 net/ipv4/route.c:1613\n ip_route_input_slow+0x1817/0x3a20 net/ipv4/route.c:234\n---truncated---",
"id": "GHSA-rpv2-375w-83vr",
"modified": "2024-03-04T18:30:39Z",
"published": "2024-03-04T18:30:39Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-47103"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0249a4b8a554f2eb6a27b62516fa50168584faa4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/68c34ce11ef23328692aa35fa6aaafdd75913100"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/75a578000ae5e511e5d0e8433c94a14d9c99c412"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8f905c0e7354ef261360fb7535ea079b1082c105"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/92e6e36ecd16808866ac6172b9491b5097cde449"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c3bb4a7e8cbc984e1cdac0fe6af60e880214ed6e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f039b43cbaea5e0700980c2f0052da05a70782e0"
}
],
"schema_version": "1.4.0",
"severity": []
}
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- 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.