cbcvebase.
CVE-2021-47572
published 2024-05-24

CVE-2021-47572: In the Linux kernel, the following vulnerability has been resolved: net: nexthop: fix null pointer dereference when IPv6 is not enabled When we try to add an…

PriorityP419medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.21%
11.0th percentile
In the Linux kernel, the following vulnerability has been resolved: net: nexthop: fix null pointer dereference when IPv6 is not enabled When we try to add an IPv6 nexthop and IPv6 is not enabled (!CONFIG_IPV6) we'll hit a NULL pointer dereference[1] in the error path of nh_create_ipv6() due to calling ipv6_stub->fib6_nh_release. The bug has been present since the beginning of IPv6 nexthop gateway support. Commit 1aefd3de7bc6 ("ipv6: Add fib6_nh_init and release to stubs") tells us that only fib6_nh_init has a dummy stub because fib6_nh_release should not be called if fib6_nh_init returns an error, but the commit below added a call to ipv6_stub->fib6_nh_release in its error path. To fix it return the dummy stub's -EAFNOSUPPORT error directly without calling ipv6_stub->fib6_nh_release in nh_create_ipv6()'s error path. [1] Output is a bit truncated, but it clearly shows the error. BUG: kernel NULL pointer dereference, address: 000000000000000000 #PF: supervisor instruction fetch in kernel modede #PF: error_code(0x0010) - not-present pagege PGD 0 P4D 0 Oops: 0010 [#1] PREEMPT SMP NOPTI CPU: 4 PID: 638 Comm: ip Kdump: loaded Not tainted 5.16.0-rc1+ #446 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-4.fc34 04/01/2014 RIP: 0010:0x0 Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. RSP: 0018:ffff888109f5b8f0 EFLAGS: 00010286^Ac RAX: 0000000000000000 RBX: ffff888109f5ba28 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8881008a2860 RBP: ffff888109f5b9d8 R08: 0000000000000000 R09: 0000000000000000 R10: ffff888109f5b978 R11: ffff888109f5b948 R12: 00000000ffffff9f R13: ffff8881008a2a80 R14: ffff8881008a2860 R15: ffff8881008a2840 FS: 00007f98de70f100(0000) GS:ffff88822bf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 0000000100efc000 CR4: 00000000000006e0 Call Trace: nh_create_ipv6+0xed/0x10c rtm_new_nexthop+0x6d7/0x13f3 ? check_preemption_disabled+0x3d

Affected

13 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 5.15.15-1 (bookworm)linux 5.15.15-1 (bookworm)
linuxlinux
linuxlinux>= 53010f991a9f5e4ed2db705ddde6ff32709192a2 < 7b6f44856da5ba0b1aa61403eb9fddd2721565037b6f44856da5ba0b1aa61403eb9fddd272156503
linuxlinux>= 53010f991a9f5e4ed2db705ddde6ff32709192a2 < b70ff391deeec35cdd8a05f5f63f5fe28bc4f225b70ff391deeec35cdd8a05f5f63f5fe28bc4f225
linuxlinux>= 53010f991a9f5e4ed2db705ddde6ff32709192a2 < 39509d76a9a3d02f379d52cb4b1449469c56c0e039509d76a9a3d02f379d52cb4b1449469c56c0e0
linuxlinux>= 53010f991a9f5e4ed2db705ddde6ff32709192a2 < 1c743127cc54b112b155f434756bd4b5fa565a991c743127cc54b112b155f434756bd4b5fa565a99
linuxlinux_kernel>= 0 < 5.10.84-15.10.84-1
linuxlinux_kernel>= 0 < 5.15.15-15.15.15-1
linuxlinux_kernel>= 0 < 5.15.15-15.15.15-1
linuxlinux_kernel>= 0 < 5.15.15-15.15.15-1
linuxlinux_kernel>= 5.11 < 5.15.65.15.6
linuxlinux_kernel>= 5.3 < 5.4.1635.4.163
linuxlinux_kernel>= 5.5 < 5.10.835.10.83

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_debian5.5MEDIUM
vendor_redhat5.5MEDIUM
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