CVE-2024-26721

Published Apr 3, 2024

Last updated a year ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: drm/i915/dsc: Fix the macro that calculates DSCC_/DSCA_ PPS reg address Commit bd077259d0a9 ("drm/i915/vdsc: Add function to read any PPS register") defines a new macro to calculate the DSC PPS register addresses with PPS number as an input. This macro correctly calculates the addresses till PPS 11 since the addresses increment by 4. So in that case the following macro works correctly to give correct register address: _MMIO(_DSCA_PPS_0 + (pps) * 4) However after PPS 11, the register address for PPS 12 increments by 12 because of RC Buffer memory allocation in between. Because of this discontinuity in the address space, the macro calculates wrong addresses for PPS 12 - 16 resulting into incorrect DSC PPS parameter value read/writes causing DSC corruption. This fixes it by correcting this macro to add the offset of 12 for PPS >=12. v3: Add correct paranthesis for pps argument (Jani Nikula) (cherry picked from commit 6074be620c31dc2ae11af96a1a5ea95580976fb5)
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
CWE-131

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged allocation path In __ip6_append_data(), when the paged-allocation branch is taken (MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap (datalen = length + fraggap). When fraggap is non-zero, this is not the first skb and transhdrlen is zero. The fraggap bytes carried over from the previous skb are copied just past the fragment headers in the new skb's linear area. The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount, and the copy writes past skb->end into the trailing skb_shared_info. An unprivileged user can trigger this via a UDPv6 socket using MSG_MORE together with MSG_SPLICE_PAGES. The bad accounting was introduced by commit 773ba4fe9104 ("ipv6: avoid partial copy for zc"). Before commit ce650a166335 ("udp6: Fix __ip6_append_data()'s handling of MSG_SPLICE_PAGES"), the negative copy value caused -EINVAL to be returned. That later commit allowed MSG_SPLICE_PAGES to proceed in this case, making the corruption triggerable. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic. Since a negative copy is no longer expected for a valid MSG_SPLICE_PAGES case, remove the MSG_SPLICE_PAGES exception from the negative copy check.CVE-2026-53362