| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2021-47175: net/sched: fq_pie: fix OOB access in the traffic path |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| net/sched: fq_pie: fix OOB access in the traffic path |
| |
| the following script: |
| |
| # tc qdisc add dev eth0 handle 0x1 root fq_pie flows 2 |
| # tc qdisc add dev eth0 clsact |
| # tc filter add dev eth0 egress matchall action skbedit priority 0x10002 |
| # ping 192.0.2.2 -I eth0 -c2 -w1 -q |
| |
| produces the following splat: |
| |
| BUG: KASAN: slab-out-of-bounds in fq_pie_qdisc_enqueue+0x1314/0x19d0 [sch_fq_pie] |
| Read of size 4 at addr ffff888171306924 by task ping/942 |
| |
| CPU: 3 PID: 942 Comm: ping Not tainted 5.12.0+ #441 |
| Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 |
| Call Trace: |
| dump_stack+0x92/0xc1 |
| print_address_description.constprop.7+0x1a/0x150 |
| kasan_report.cold.13+0x7f/0x111 |
| fq_pie_qdisc_enqueue+0x1314/0x19d0 [sch_fq_pie] |
| __dev_queue_xmit+0x1034/0x2b10 |
| ip_finish_output2+0xc62/0x2120 |
| __ip_finish_output+0x553/0xea0 |
| ip_output+0x1ca/0x4d0 |
| ip_send_skb+0x37/0xa0 |
| raw_sendmsg+0x1c4b/0x2d00 |
| sock_sendmsg+0xdb/0x110 |
| __sys_sendto+0x1d7/0x2b0 |
| __x64_sys_sendto+0xdd/0x1b0 |
| do_syscall_64+0x3c/0x80 |
| entry_SYSCALL_64_after_hwframe+0x44/0xae |
| RIP: 0033:0x7fe69735c3eb |
| 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 <48> 3d 00 f0 ff ff 77 75 c3 0f 1f 40 00 41 57 4d 89 c7 41 56 41 89 |
| RSP: 002b:00007fff06d7fb38 EFLAGS: 00000246 ORIG_RAX: 000000000000002c |
| RAX: ffffffffffffffda RBX: 000055e961413700 RCX: 00007fe69735c3eb |
| RDX: 0000000000000040 RSI: 000055e961413700 RDI: 0000000000000003 |
| RBP: 0000000000000040 R08: 000055e961410500 R09: 0000000000000010 |
| R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff06d81260 |
| R13: 00007fff06d7fb40 R14: 00007fff06d7fc30 R15: 000055e96140f0a0 |
| |
| Allocated by task 917: |
| kasan_save_stack+0x19/0x40 |
| __kasan_kmalloc+0x7f/0xa0 |
| __kmalloc_node+0x139/0x280 |
| fq_pie_init+0x555/0x8e8 [sch_fq_pie] |
| qdisc_create+0x407/0x11b0 |
| tc_modify_qdisc+0x3c2/0x17e0 |
| rtnetlink_rcv_msg+0x346/0x8e0 |
| netlink_rcv_skb+0x120/0x380 |
| netlink_unicast+0x439/0x630 |
| netlink_sendmsg+0x719/0xbf0 |
| sock_sendmsg+0xe2/0x110 |
| ____sys_sendmsg+0x5ba/0x890 |
| ___sys_sendmsg+0xe9/0x160 |
| __sys_sendmsg+0xd3/0x170 |
| do_syscall_64+0x3c/0x80 |
| entry_SYSCALL_64_after_hwframe+0x44/0xae |
| |
| The buggy address belongs to the object at ffff888171306800 |
| which belongs to the cache kmalloc-256 of size 256 |
| The buggy address is located 36 bytes to the right of |
| 256-byte region [ffff888171306800, ffff888171306900) |
| The buggy address belongs to the page: |
| page:00000000bcfb624e refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x171306 |
| head:00000000bcfb624e order:1 compound_mapcount:0 |
| flags: 0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff) |
| raw: 0017ffffc0010200 dead000000000100 dead000000000122 ffff888100042b40 |
| raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 |
| page dumped because: kasan: bad access detected |
| |
| Memory state around the buggy address: |
| ffff888171306800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |
| ffff888171306880: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc |
| >ffff888171306900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc |
| ^ |
| ffff888171306980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc |
| ffff888171306a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| |
| fix fq_pie traffic path to avoid selecting 'q->flows + q->flows_cnt' as a |
| valid flow: it's an address beyond the allocated memory. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47175 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.6 with commit ec97ecf1ebe485a17cd8395a5f35e6b80b57665a and fixed in 5.10.42 with commit e6294c06e7c62ffdd5bf3df696d3a4fcbb753d3c |
| Issue introduced in 5.6 with commit ec97ecf1ebe485a17cd8395a5f35e6b80b57665a and fixed in 5.12.9 with commit 7a1bdec12e43e29cc34a4394590337069d8812ce |
| Issue introduced in 5.6 with commit ec97ecf1ebe485a17cd8395a5f35e6b80b57665a and fixed in 5.13 with commit e70f7a11876a1a788ceadf75e9e5f7af2c868680 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2021-47175 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| net/sched/sch_fq_pie.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/e6294c06e7c62ffdd5bf3df696d3a4fcbb753d3c |
| https://git.kernel.org/stable/c/7a1bdec12e43e29cc34a4394590337069d8812ce |
| https://git.kernel.org/stable/c/e70f7a11876a1a788ceadf75e9e5f7af2c868680 |
