Integer Underflow Affecting kernel-core package, versions *


Severity

Recommended
low

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.05% (18th percentile)

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  • Snyk IDSNYK-RHEL8-KERNELCORE-7038858
  • published23 May 2024
  • disclosed22 May 2024

Introduced: 22 May 2024

CVE-2021-47496  (opens in a new tab)
CWE-191  (opens in a new tab)
CWE-124  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:8 kernel-core.

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:

net/tls: Fix flipped sign in tls_err_abort() calls

sk->sk_err appears to expect a positive value, a convention that ktls doesn't always follow and that leads to memory corruption in other code. For instance,

[kworker]
tls_encrypt_done(..., err=<negative error from crypto request>)
  tls_err_abort(.., err)
    sk->sk_err = err;

[task] splice_from_pipe_feed ... tls_sw_do_sendpage if (sk->sk_err) { ret = -sk->sk_err; // ret is positive

splice_from_pipe_feed (continued) ret = actor(...) // ret is still positive and interpreted as bytes // written, resulting in underflow of buf->len and // sd->len, leading to huge buf->offset and bogus // addresses computed in later calls to actor()

Fix all tls_err_abort() callers to pass a negative error code consistently and centralize the error-prone sign flip there, throwing in a warning to catch future misuse and uninlining the function so it really does only warn once.

CVSS Scores

version 3.1