openvswitch: fix stack OOB read while fragmenting IPv4 packets

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2021-46955
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2024-02-27 19:04:06 UTC
Updated2026-08-04 10:16:37 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: openvswitch: fix stack OOB read while fragmenting IPv4 packets running openvswitch on kernels built with KASAN, it's possible to see the following splat while testing fragmentation of IPv4 packets: BUG: KASAN: stack-out-of-bounds in ip_do_fragment+0x1b03/0x1f60 Read of size 1 at addr ffff888112fc713c by task handler2/1367 CPU: 0 PID: 1367 Comm: handler2 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: dump_stack+0x92/0xc1 print_address_description.constprop.7+0x1a/0x150 kasan_report.cold.13+0x7f/0x111 ip_do_fragment+0x1b03/0x1f60 ovs_fragment+0x5bf/0x840 [openvswitch] do_execute_actions+0x1bd5/0x2400 [openvswitch] ovs_execute_actions+0xc8/0x3d0 [openvswitch] ovs_packet_cmd_execute+0xa39/0x1150 [openvswitch] genl_family_rcv_msg_doit.isra.15+0x227/0x2d0 genl_rcv_msg+0x287/0x490 netlink_rcv_skb+0x120/0x380 genl_rcv+0x24/0x40 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+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f957079db07 Code: c3 66 90 41 54 41 89 d4 55 48 89 f5 53 89 fb 48 83 ec 10 e8 eb ec ff ff 44 89 e2 48 89 ee 89 df 41 89 c0 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 48 89 44 24 08 e8 24 ed ff ff 48 RSP: 002b:00007f956ce35a50 EFLAGS: 00000293 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000019 RCX: 00007f957079db07 RDX: 0000000000000000 RSI: 00007f956ce35ae0 RDI: 0000000000000019 RBP: 00007f956ce35ae0 R08: 0000000000000000 R09: 00007f9558006730 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007f956ce37308 R14: 00007f956ce35f80 R15: 00007f956ce35ae0 The buggy address belongs to the page: page:00000000af2a1d93 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x112fc7 flags: 0x17ffffc0000000() raw: 0017ffffc0000000 0000000000000000 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected addr ffff888112fc713c is located in stack of task handler2/1367 at offset 180 in frame: ovs_fragment+0x0/0x840 [openvswitch] this frame has 2 objects: [32, 144) 'ovs_dst' [192, 424) 'ovs_rt' Memory state around the buggy address: ffff888112fc7000: f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888112fc7080: 00 f1 f1 f1 f1 00 00 00 00 00 00 00 00 00 00 00 >ffff888112fc7100: 00 00 00 f2 f2 f2 f2 f2 f2 00 00 00 00 00 00 00 ^ ffff888112fc7180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888112fc7200: 00 00 00 00 00 00 f2 f2 f2 00 00 00 00 00 00 00 for IPv4 packets, ovs_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 ovs_fragment(), similarly to what is done for IPv6 few lines below.

Risk And Classification

Primary CVSS: v3.1 7.1 HIGH from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Problem Types: CWE-125

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary7.1HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary8.2HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
3.1CNADECLARED8.2HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 119bbaa6795a4f4aed46994cc7d9ab01989c87e3 b1d7280f9ba1bfdbc3af5bdb82e51f014854f26f git Not specified
CNA Linux Linux affected d543907a4730400f5c5b684c57cb5bbbfd6136ab 23e17ec1a5eb53fe39cc34fa5592686d5acd0dac git Not specified
CNA Linux Linux affected 8387fbac8e18e26a60559adc63e0b7067303b0a4 5a52fa8ad45b5a593ed416adf326538638454ff1 git Not specified
CNA Linux Linux affected d52e5a7e7ca49457dd31fc8b42fb7c0d58a31221 df9e900de24637be41879e2c50afb713ec4e8b2e git Not specified
CNA Linux Linux affected d52e5a7e7ca49457dd31fc8b42fb7c0d58a31221 490ad0a2390442d0a7b8c00972a83dbb09cab142 git Not specified
CNA Linux Linux affected d52e5a7e7ca49457dd31fc8b42fb7c0d58a31221 a1478374b0bda89b4277a8afd39208271faad4be git Not specified
CNA Linux Linux affected d52e5a7e7ca49457dd31fc8b42fb7c0d58a31221 d841d3cf5297fde4ce6a41ff35451d0e82917f3e git Not specified
CNA Linux Linux affected d52e5a7e7ca49457dd31fc8b42fb7c0d58a31221 b3502b04e84ac5349be95fc033c17bd701d2787a git Not specified
CNA Linux Linux affected d52e5a7e7ca49457dd31fc8b42fb7c0d58a31221 7c0ea5930c1c211931819d83cfb157bff1539a4c git Not specified
CNA Linux Linux affected df9ece1148e2ec242871623dedb004f7a1387125 git Not specified
CNA Linux Linux affected 4.4.134 4.4.269 semver Not specified
CNA Linux Linux affected 4.9.104 4.9.269 semver Not specified
CNA Linux Linux affected 4.14.45 4.14.233 semver Not specified
CNA Linux Linux affected 3.16.57 3.17 semver Not specified
CNA Linux Linux affected 4.16 Not specified
CNA Linux Linux unaffected 4.16 semver Not specified
CNA Linux Linux unaffected 4.4.269 4.4.* semver Not specified
CNA Linux Linux unaffected 4.9.269 4.9.* semver Not specified
CNA Linux Linux unaffected 4.14.233 4.14.* semver Not specified
CNA Linux Linux unaffected 4.19.191 4.19.* semver Not specified
CNA Linux Linux unaffected 5.4.118 5.4.* semver Not specified
CNA Linux Linux unaffected 5.10.36 5.10.* semver Not specified
CNA Linux Linux unaffected 5.11.20 5.11.* semver Not specified
CNA Linux Linux unaffected 5.12.3 5.12.* semver Not specified
CNA Linux Linux unaffected 5.13 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/23e17ec1a5eb53fe39cc34fa5592686d5acd0dac af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/a1478374b0bda89b4277a8afd39208271faad4be af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/d841d3cf5297fde4ce6a41ff35451d0e82917f3e af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/7c0ea5930c1c211931819d83cfb157bff1539a4c af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/b3502b04e84ac5349be95fc033c17bd701d2787a af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/df9e900de24637be41879e2c50afb713ec4e8b2e af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/b1d7280f9ba1bfdbc3af5bdb82e51f014854f26f af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/5a52fa8ad45b5a593ed416adf326538638454ff1 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/490ad0a2390442d0a7b8c00972a83dbb09cab142 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
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