ghsa-6jf4-4jp9-4wmw
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
net/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets
when 'act_mirred' tries to fragment IPv4 packets that had been previously re-assembled using 'act_ct', splats like the following can be observed on kernels built with KASAN:
BUG: KASAN: stack-out-of-bounds in ip_do_fragment+0x1b03/0x1f60 Read of size 1 at addr ffff888147009574 by task ping/947
CPU: 0 PID: 947 Comm: ping Not tainted 5.12.0-rc6+ #418
Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014
Call Trace:
The buggy address belongs to the page: page:000000001dff2e03 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x147009 flags: 0x17ffffc0001000(reserved) raw: 0017ffffc0001000 ffffea00051c0248 ffffea00051c0248 0000000000000000 raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected
Memory state around the buggy address: ffff888147009400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888147009480: f1 f1 f1 f1 04 f2 f2 f2 f2 f2 f2 f2 00 00 00 00
ffff888147009500: 00 00 00 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 f2 ^ ffff888147009580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888147009600: 00 00 00 00 00 00 00 00 00 00 00 00 00 f2 f2 f2
for IPv4 packets, sch_fragment() uses a temporary struct dst_entry. Then, in the following call graph:
ip_do_fragment() ip_skb_dst_mtu() ip_dst_mtu_maybe_forward() ip_mtu_locked()
the pointer to struct dst_entry is used as pointer to struct rtable: this turns the access to struct members like rt_mtu_locked into an OOB read in the stack. Fix this changing the temporary variable used for IPv4 packets in sch_fragment(), similarly to what is done for IPv6 few lines below.
{
"affected": [],
"aliases": [
"CVE-2021-46954"
],
"database_specific": {
"cwe_ids": [
"CWE-125"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-02-27T19:04:06Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets\n\nwhen \u0027act_mirred\u0027 tries to fragment IPv4 packets that had been previously\nre-assembled using \u0027act_ct\u0027, splats like the following can be observed on\nkernels built with KASAN:\n\n BUG: KASAN: stack-out-of-bounds in ip_do_fragment+0x1b03/0x1f60\n Read of size 1 at addr ffff888147009574 by task ping/947\n\n CPU: 0 PID: 947 Comm: ping Not tainted 5.12.0-rc6+ #418\n Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014\n Call Trace:\n \u003cIRQ\u003e\n dump_stack+0x92/0xc1\n print_address_description.constprop.7+0x1a/0x150\n kasan_report.cold.13+0x7f/0x111\n ip_do_fragment+0x1b03/0x1f60\n sch_fragment+0x4bf/0xe40\n tcf_mirred_act+0xc3d/0x11a0 [act_mirred]\n tcf_action_exec+0x104/0x3e0\n fl_classify+0x49a/0x5e0 [cls_flower]\n tcf_classify_ingress+0x18a/0x820\n __netif_receive_skb_core+0xae7/0x3340\n __netif_receive_skb_one_core+0xb6/0x1b0\n process_backlog+0x1ef/0x6c0\n __napi_poll+0xaa/0x500\n net_rx_action+0x702/0xac0\n __do_softirq+0x1e4/0x97f\n do_softirq+0x71/0x90\n \u003c/IRQ\u003e\n __local_bh_enable_ip+0xdb/0xf0\n ip_finish_output2+0x760/0x2120\n ip_do_fragment+0x15a5/0x1f60\n __ip_finish_output+0x4c2/0xea0\n ip_output+0x1ca/0x4d0\n ip_send_skb+0x37/0xa0\n raw_sendmsg+0x1c4b/0x2d00\n sock_sendmsg+0xdb/0x110\n __sys_sendto+0x1d7/0x2b0\n __x64_sys_sendto+0xdd/0x1b0\n do_syscall_64+0x33/0x40\n entry_SYSCALL_64_after_hwframe+0x44/0xae\n RIP: 0033:0x7f82e13853eb\n Code: 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 48 8d 05 75 42 2c 00 41 89 ca 8b 00 85 c0 75 14 b8 2c 00 00 00 0f 05 \u003c48\u003e 3d 00 f0 ff ff 77 75 c3 0f 1f 40 00 41 57 4d 89 c7 41 56 41 89\n RSP: 002b:00007ffe01fad888 EFLAGS: 00000246 ORIG_RAX: 000000000000002c\n RAX: ffffffffffffffda RBX: 00005571aac13700 RCX: 00007f82e13853eb\n RDX: 0000000000002330 RSI: 00005571aac13700 RDI: 0000000000000003\n RBP: 0000000000002330 R08: 00005571aac10500 R09: 0000000000000010\n R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe01faefb0\n R13: 00007ffe01fad890 R14: 00007ffe01fad980 R15: 00005571aac0f0a0\n\n The buggy address belongs to the page:\n page:000000001dff2e03 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x147009\n flags: 0x17ffffc0001000(reserved)\n raw: 0017ffffc0001000 ffffea00051c0248 ffffea00051c0248 0000000000000000\n raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000\n page dumped because: kasan: bad access detected\n\n Memory state around the buggy address:\n ffff888147009400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n ffff888147009480: f1 f1 f1 f1 04 f2 f2 f2 f2 f2 f2 f2 00 00 00 00\n \u003effff888147009500: 00 00 00 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 f2\n ^\n ffff888147009580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n ffff888147009600: 00 00 00 00 00 00 00 00 00 00 00 00 00 f2 f2 f2\n\nfor IPv4 packets, sch_fragment() uses a temporary struct dst_entry. Then,\nin the following call graph:\n\n ip_do_fragment()\n ip_skb_dst_mtu()\n ip_dst_mtu_maybe_forward()\n ip_mtu_locked()\n\nthe pointer to struct dst_entry is used as pointer to struct rtable: this\nturns the access to struct members like rt_mtu_locked into an OOB read in\nthe stack. Fix this changing the temporary variable used for IPv4 packets\nin sch_fragment(), similarly to what is done for IPv6 few lines below.",
"id": "GHSA-6jf4-4jp9-4wmw",
"modified": "2024-04-10T21:30:29Z",
"published": "2024-02-27T21:31:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-46954"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/018bb8da5b5888e19585f9b802f036afe643fcef"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/31fe34a0118e0acc958c802e830ad5d37ef6b1d3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8e6dfb7beeb6489ac1365b8a71052e737f5da76e"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
"type": "CVSS_V3"
}
]
}