Ubuntu: (CVE-2021-4442): linux vulnerability

Ubuntu: (CVE-2021-4442): linux vulnerability

Severity

5

CVSS

(AV:L/AC:L/Au:S/C:N/I:N/A:C)

Published

08/29/2024

Created

11/21/2024

Added

11/19/2024

Modified

02/11/2025

Description

In the Linux kernel, the following vulnerability has been resolved: tcp: add sanity tests to TCP_QUEUE_SEQ Qingyu Li reported a syzkaller bug where the repro changes RCV SEQ _after_ restoring data in the receive queue. mprotect(0x4aa000, 12288, PROT_READ)= 0 mmap(0x1ffff000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x1ffff000 mmap(0x20000000, 16777216, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x20000000 mmap(0x21000000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x21000000 socket(AF_INET6, SOCK_STREAM, IPPROTO_IP) = 3 setsockopt(3, SOL_TCP, TCP_REPAIR, [1], 4) = 0 connect(3, {sa_family=AF_INET6, sin6_port=htons(0), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_scope_id=0}, 28) = 0 setsockopt(3, SOL_TCP, TCP_REPAIR_QUEUE, [1], 4) = 0 sendmsg(3, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="0x0000000000000003\0\0", iov_len=20}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 20 setsockopt(3, SOL_TCP, TCP_REPAIR, [0], 4) = 0 setsockopt(3, SOL_TCP, TCP_QUEUE_SEQ, [128], 4) = 0 recvfrom(3, NULL, 20, 0, NULL, NULL)= -1 ECONNRESET (Connection reset by peer) syslog shows: [111.205099] TCP recvmsg seq # bug 2: copied 80, seq 0, rcvnxt 80, fl 0 [111.207894] WARNING: CPU: 1 PID: 356 at net/ipv4/tcp.c:2343 tcp_recvmsg_locked+0x90e/0x29a0 This should not be allowed. TCP_QUEUE_SEQ should only be used when queues are empty. This patch fixes this case, and the tx path as well.

Solution(s)

• ubuntu-upgrade-linux
• ubuntu-upgrade-linux-aws
• ubuntu-upgrade-linux-aws-5-4
• ubuntu-upgrade-linux-aws-fips
• ubuntu-upgrade-linux-aws-hwe
• ubuntu-upgrade-linux-azure
• ubuntu-upgrade-linux-azure-4-15
• ubuntu-upgrade-linux-azure-5-4
• ubuntu-upgrade-linux-azure-fips
• ubuntu-upgrade-linux-fips
• ubuntu-upgrade-linux-gcp
• ubuntu-upgrade-linux-gcp-4-15
• ubuntu-upgrade-linux-gcp-5-4
• ubuntu-upgrade-linux-gcp-fips
• ubuntu-upgrade-linux-gkeop
• ubuntu-upgrade-linux-hwe
• ubuntu-upgrade-linux-hwe-5-4
• ubuntu-upgrade-linux-kvm
• ubuntu-upgrade-linux-oracle
• ubuntu-upgrade-linux-oracle-5-4
• ubuntu-upgrade-linux-raspi
• ubuntu-upgrade-linux-raspi-5-4

References

• https://attackerkb.com/topics/cve-2021-4442
• CVE - 2021-4442
• https://git.kernel.org/linus/8811f4a9836e31c14ecdf79d9f3cb7c5d463265d
• https://git.kernel.org/stable/c/046f3c1c2ff450fb7ae53650e9a95e0074a61f3e
• https://git.kernel.org/stable/c/319f460237fc2965a80aa9a055044e1da7b3692a
• https://git.kernel.org/stable/c/3b72d5a703842f582502d97906f17d6ee122dac2
• https://git.kernel.org/stable/c/3bf899438c123c444f6b644a57784dfbb6b15ad6
• https://git.kernel.org/stable/c/8811f4a9836e31c14ecdf79d9f3cb7c5d463265d
• https://www.cve.org/CVERecord?id=CVE-2021-4442

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