CVE-2021-47068

published 2024-02-29

CVE-2021-47068: In the Linux kernel, the following vulnerability has been resolved: net/nfc: fix use-after-free llcp_sock_bind/connect Commits 8a4cd82d ("nfc: fix refcount…

Priority P3 37 high 7.8 CVSS 3.1

AV L AC L PR L UI N S U C H I H A H

In the Linux kernel, the following vulnerability has been resolved:

net/nfc: fix use-after-free llcp_sock_bind/connect

Commits 8a4cd82d ("nfc: fix refcount leak in llcp_sock_connect()")
and c33b1cc62 ("nfc: fix refcount leak in llcp_sock_bind()")
fixed a refcount leak bug in bind/connect but introduced a
use-after-free if the same local is assigned to 2 different sockets.

This can be triggered by the following simple program:
int sock1 = socket( AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP );
int sock2 = socket( AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP );
memset( &addr, 0, sizeof(struct sockaddr_nfc_llcp) );
addr.sa_family = AF_NFC;
addr.nfc_protocol = NFC_PROTO_NFC_DEP;
bind( sock1, (struct sockaddr*) &addr, sizeof(struct sockaddr_nfc_llcp) )
bind( sock2, (struct sockaddr*) &addr, sizeof(struct sockaddr_nfc_llcp) )
close(sock1);
close(sock2);

Fix this by assigning NULL to llcp_sock->local after calling
nfc_llcp_local_put.

This addresses CVE-2021-23134.

Affected

13 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 5.10.38-1 (bookworm)	linux 5.10.38-1 (bookworm)
linux	linux_kernel	>= 0 < 5.10.38-1	5.10.38-1
linux	linux_kernel	>= 0 < 5.10.38-1	5.10.38-1
linux	linux_kernel	>= 0 < 5.10.38-1	5.10.38-1
linux	linux_kernel	>= 0 < 5.10.38-1	5.10.38-1
linux	linux_kernel	>= 4.14.231 < 4.14.233	4.14.233
linux	linux_kernel	>= 4.19.187 < 4.19.191	4.19.191
linux	linux_kernel	>= 4.4.267 < 4.4.269	4.4.269
linux	linux_kernel	>= 4.9.267 < 4.9.269	4.9.269
linux	linux_kernel	>= 5.10.30 < 5.10.37	5.10.37
linux	linux_kernel	>= 5.11.14 < 5.11.21	5.11.21
linux	linux_kernel	>= 5.12 < 5.12.4	5.12.4
linux	linux_kernel	>= 5.4.112 < 5.4.119	5.4.119

CVSS provenance

nvd v3.1 7.8 HIGH CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

osv 7.8 HIGH

vendor_debian 7.8 HIGH

vendor_redhat 7.8 HIGH

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