Improper Input Validation Affecting kernel-core package, versions <0:4.18.0-348.el8


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.05% (19th percentile)

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  • Snyk IDSNYK-RHEL8-KERNELCORE-7854565
  • published30 Aug 2024
  • disclosed29 Aug 2024

Introduced: 29 Aug 2024

CVE-2021-4442  (opens in a new tab)
CWE-20  (opens in a new tab)

How to fix?

Upgrade RHEL:8 kernel-core to version 0:4.18.0-348.el8 or higher.
This issue was patched in RHSA-2021:4356.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-core package and not the kernel-core package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

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.

CVSS Scores

version 3.1