CVE-2024-26755

Published Apr 3, 2024

Last updated a year ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: md: Don't suspend the array for interrupted reshape md_start_sync() will suspend the array if there are spares that can be added or removed from conf, however, if reshape is still in progress, this won't happen at all or data will be corrupted(remove_and_add_spares won't be called from md_choose_sync_action for reshape), hence there is no need to suspend the array if reshape is not done yet. Meanwhile, there is a potential deadlock for raid456: 1) reshape is interrupted; 2) set one of the disk WantReplacement, and add a new disk to the array, however, recovery won't start until the reshape is finished; 3) then issue an IO across reshpae position, this IO will wait for reshape to make progress; 4) continue to reshape, then md_start_sync() found there is a spare disk that can be added to conf, mddev_suspend() is called; Step 4 and step 3 is waiting for each other, deadlock triggered. Noted this problem is found by code review, and it's not reporduced yet. Fix this porblem by don't suspend the array for interrupted reshape, this is safe because conf won't be changed until reshape is done.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Secondary
Base score
5.3
Impact score
1.4
Exploitability score
3.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Severity
MEDIUM

Weaknesses

nvd@nist.gov
CWE-129

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