{ "containers": { "cna": { "providerMetadata": { "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038" }, "descriptions": [ { "lang": "en", "value": "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 'act_mirred' tries to fragment IPv4 packets that had been previously\nre-assembled using 'act_ct', 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 \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 \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 <48> 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 >ffff888147009500: 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." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sched/sch_frag.c" ], "versions": [ { "version": "c129412f74e9", "lessThan": "018bb8da5b58", "status": "affected", "versionType": "git" }, { "version": "c129412f74e9", "lessThan": "8e6dfb7beeb6", "status": "affected", "versionType": "git" }, { "version": "c129412f74e9", "lessThan": "31fe34a0118e", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sched/sch_frag.c" ], "versions": [ { "version": "5.11", "status": "affected" }, { "version": "0", "lessThan": "5.11", "status": "unaffected", "versionType": "custom" }, { "version": "5.11.20", "lessThanOrEqual": "5.11.*", "status": "unaffected", "versionType": "custom" }, { "version": "5.12.3", "lessThanOrEqual": "5.12.*", "status": "unaffected", "versionType": "custom" }, { "version": "5.13", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/018bb8da5b5888e19585f9b802f036afe643fcef" }, { "url": "https://git.kernel.org/stable/c/8e6dfb7beeb6489ac1365b8a71052e737f5da76e" }, { "url": "https://git.kernel.org/stable/c/31fe34a0118e0acc958c802e830ad5d37ef6b1d3" } ], "title": "net/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets", "x_generator": { "engine": "bippy-a5840b7849dd" } } }, "cveMetadata": { "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038", "cveID": "CVE-2021-46954", "requesterUserId": "gregkh@kernel.org", "serial": "1", "state": "PUBLISHED" }, "dataType": "CVE_RECORD", "dataVersion": "5.0" }