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Unscored CVE-2024-42305 EUVD-2024-39528GHSA-46jx-3cg2-9964

ext4: check dot and dotdot of dx_root before making dir indexed

Published Aug 17, 2024 · Updated Oct 15, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: linux Package: linux Package: linux-allwinner-5.19 Package: linux-aws Package: linux-aws-5.0 Package: linux-aws-5.11 Package: linux-aws-5.13 Package: linux-aws-5.15 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.4 Package: linux-aws-5.8 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-aws-6.8 Package: linux-aws-fips Package: linux-aws-hwe Package: linux-azure Package: linux-azure-4.15 Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.15 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.4 Package: linux-azure-5.8 Package: linux-azure-6.2 Package: linux-azure-6.5 Package: linux-azure-6.8 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.2 Package: linux-azure-fips Package: linux-bluefield Package: linux-fips Package: linux-gcp Package: linux-gcp-4.15 Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.15 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.4 Package: linux-gcp-5.8 Package: linux-gcp-6.2 Package: linux-gcp-6.5 Package: linux-gcp-6.8 Package: linux-gcp-fips Package: linux-gke Package: linux-gke-4.15 Package: linux-gke-5.15 Package: linux-gke-5.4 Package: linux-gkeop Package: linux-gkeop-5.15 Package: linux-gkeop-5.4 Package: linux-hwe Package: linux-hwe-5.11 Package: linux-hwe-5.13 Package: linux-hwe-5.15 Package: linux-hwe-5.19 Package: linux-hwe-5.4 Package: linux-hwe-5.8 Package: linux-hwe-6.2 Package: linux-hwe-6.5 Package: linux-hwe-6.8 Package: linux-hwe-edge Package: linux-ibm Package: linux-ibm-5.15 Package: linux-ibm-5.4 Package: linux-ibm-6.8 Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-intel-iotg Package: linux-intel-iotg-5.15 Package: linux-iot Package: linux-kvm Package: linux-lowlatency Package: linux-lowlatency-hwe-5.15 Package: linux-lowlatency-hwe-5.19 Package: linux-lowlatency-hwe-6.2 Package: linux-lowlatency-hwe-6.5 Package: linux-lowlatency-hwe-6.8 Package: linux-lts-xenial Package: linux-nvidia Package: linux-nvidia-6.2 Package: linux-nvidia-6.5 Package: linux-nvidia-6.8 Package: linux-nvidia-lowlatency Package: linux-nvidia-tegra Package: linux-nvidia-tegra-5.15 Package: linux-nvidia-tegra-igx Package: linux-oem Package: linux-oem-5.10 Package: linux-oem-5.13 Package: linux-oem-5.14 Package: linux-oem-5.17 Package: linux-oem-5.6 Package: linux-oem-6.0 Package: linux-oem-6.1 Package: linux-oem-6.5 Package: linux-oem-6.8 Package: linux-oracle Package: linux-oracle-5.0 Package: linux-oracle-5.11 Package: linux-oracle-5.13 Package: linux-oracle-5.15 Package: linux-oracle-5.3 Package: linux-oracle-5.4 Package: linux-oracle-5.8 Package: linux-oracle-6.5 Package: linux-oracle-6.8 Package: linux-raspi Package: linux-raspi-5.4 Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.8 Package: linux-riscv Package: linux-riscv-5.11 Package: linux-riscv-5.15 Package: linux-riscv-5.19 Package: linux-riscv-5.8 Package: linux-riscv-6.5 Package: linux-riscv-6.8 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Package: linux-starfive-6.5 Package: linux-vmware Package: linux-xilinx Package: linux-xilinx-zynqmp Platform: Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

In the Linux kernel, the following vulnerability has been resolved:

ext4: check dot and dotdot of dx_root before making dir indexed

Syzbot reports a issue as follows:
============================================
BUG: unable to handle page fault for address: ffffed11022e24fe
PGD 23ffee067 P4D 23ffee067 PUD 0
Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 0 PID: 5079 Comm: syz-executor306 Not tainted 6.10.0-rc5-g55027e689933 #0
Call Trace:
<TASK>
make_indexed_dir+0xdaf/0x13c0 fs/ext4/namei.c:2341
ext4_add_entry+0x222a/0x25d0 fs/ext4/namei.c:2451
ext4_rename fs/ext4/namei.c:3936 [inline]
ext4_rename2+0x26e5/0x4370 fs/ext4/namei.c:4214
[...]
============================================

The immediate cause of this problem is that there is only one valid dentry
for the block to be split during do_split, so split==0 results in out of
bounds accesses to the map triggering the issue.

do_split
unsigned split
dx_make_map
count = 1
split = count/2 = 0;
continued = hash2 == map[split - 1].hash;
---> map[4294967295]

The maximum length of a filename is 255 and the minimum block size is 1024,
so it is always guaranteed that the number of entries is greater than or
equal to 2 when do_split() is called.

But syzbot's crafted image has no dot and dotdot in dir, and the dentry
distribution in dirblock is as follows:

bus dentry1 hole dentry2 free
|xx--|xx-------------|...............|xx-------------|...............|
0 12 (8+248)=256 268 256 524 (8+256)=264 788 236 1024

So when renaming dentry1 increases its name_len length by 1, neither hole
nor free is sufficient to hold the new dentry, and make_indexed_dir() is
called.

In make_indexed_dir() it is assumed that the first two entries of the
dirblock must be dot and dotdot, so bus and dentry1 are left in dx_root
because they are treated as dot and dotdot, and only dentry2 is moved
to the new leaf block. That's why count is equal to 1.

Therefore add the ext4_check_dx_root() helper function to add more sanity
checks to dot and dotdot before starting the conversion to avoid the above
issue.

Affected products

VendorProductAffectedFixed
Linux Linux 2.6.19 4.19.320

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 linux 6.10.3-1 —
Debian 13 linux 6.10.3-1 —
Debian 12 linux 6.1.106-1 —
Debian 11 linux 5.10.226-1 DLA-3912-1
Debian 11 linux-6.1 6.1.119-1~deb11u1 DLA-4008-1
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield 5.15.0-1056.58 —
Ubuntu 24.04 LTS linux 6.8.0-50.51 USN-7154-1
Ubuntu 24.04 LTS linux-aws 6.8.0-1020.22 USN-7154-1
Ubuntu 24.04 LTS linux-azure 6.8.0-1020.23 USN-7196-1
Ubuntu 24.04 LTS linux-gcp +1 6.8.0-1019.21 USN-7155-1, USN-7154-1
Ubuntu 24.04 LTS linux-gke 6.8.0-1015.19 USN-7154-1
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1002.4 USN-7156-1
Ubuntu 24.04 LTS linux-ibm 6.8.0-1017.17 USN-7154-1
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1019.21.1 USN-7155-1
Ubuntu 24.04 LTS linux-oem-6.8 6.8.0-1018.18 USN-7154-1
Ubuntu 24.04 LTS linux-oracle +1 6.8.0-1017.18 USN-7154-1
Ubuntu 24.04 LTS linux-raspi 6.8.0-1016.18 USN-7154-1
Ubuntu 24.04 LTS linux-riscv +1 6.8.0-50.51.1 USN-7154-1
Ubuntu 22.04 LTS linux +1 5.15.0-125.135 USN-7100-1
Ubuntu 22.04 LTS linux-aws 5.15.0-1072.78 USN-7100-2
Ubuntu 22.04 LTS linux-aws-6.8 6.8.0-1020.22~22.04.1 USN-7154-1
Ubuntu 22.04 LTS linux-azure 5.15.0-1075.84 USN-7123-1
Ubuntu 22.04 LTS linux-azure-6.8 6.8.0-1020.23~22.04.1 USN-7196-1
Ubuntu 22.04 LTS linux-azure-fde 5.15.0-1076.85.1 —
Ubuntu 22.04 LTS linux-gcp 5.15.0-1071.79 USN-7100-1
Ubuntu 22.04 LTS linux-gcp-6.8 +1 6.8.0-1019.21~22.04.1 USN-7155-1, USN-7154-1
Ubuntu 22.04 LTS linux-gke 5.15.0-1069.75 USN-7100-1
Ubuntu 22.04 LTS linux-gkeop 5.15.0-1055.62 USN-7100-1
Ubuntu 22.04 LTS linux-hwe-6.8 6.8.0-50.51~22.04.1 USN-7154-2
Ubuntu 22.04 LTS linux-ibm +1 5.15.0-1065.68 USN-7100-1
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1017.17~22.04.1 —
Ubuntu 22.04 LTS linux-intel-iotg 5.15.0-1067.73 USN-7144-1
Ubuntu 22.04 LTS linux-kvm 5.15.0-1069.74 USN-7100-1
Ubuntu 22.04 LTS linux-nvidia 5.15.0-1067.68 USN-7100-1
Ubuntu 22.04 LTS linux-nvidia-tegra 5.15.0-1032.32 —
Ubuntu 22.04 LTS linux-nvidia-tegra-igx 5.15.0-1020.20 —
Ubuntu 22.04 LTS linux-oracle 5.15.0-1070.76 USN-7100-1
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1017.18~22.04.1 USN-7154-1
Ubuntu 22.04 LTS linux-riscv +31 No fix yet —
Ubuntu 22.04 LTS linux-riscv-6.8 +1 6.8.0-50.51.1~22.04.1 USN-7154-1
Ubuntu 22.04 LTS linux-xilinx-zynqmp 5.15.0-1038.42 USN-7100-1
Ubuntu 20.04 LTS linux 5.4.0-200.220 USN-7088-1
Ubuntu 20.04 LTS linux-aws 5.4.0-1135.145 USN-7088-4
Ubuntu 20.04 LTS linux-aws-5.15 5.15.0-1072.78~20.04.1 USN-7100-1
Ubuntu 20.04 LTS linux-azure 5.4.0-1140.147 USN-7088-2
Ubuntu 20.04 LTS linux-azure-5.15 5.15.0-1078.87~20.04.1 USN-7194-1
Ubuntu 20.04 LTS linux-bluefield 5.4.0-1095.102 USN-7088-2
Ubuntu 20.04 LTS linux-gcp 5.4.0-1139.148 USN-7088-1
Ubuntu 20.04 LTS linux-gcp-5.15 5.15.0-1071.79~20.04.1 USN-7100-1
Ubuntu 20.04 LTS linux-gke +26 No fix yet —
Ubuntu 20.04 LTS linux-gkeop 5.4.0-1102.106 USN-7088-1
Ubuntu 20.04 LTS linux-gkeop-5.15 5.15.0-1055.62~20.04.1 USN-7100-1
Ubuntu 20.04 LTS linux-hwe-5.15 +1 5.15.0-125.135~20.04.1 USN-7100-1
Ubuntu 20.04 LTS linux-ibm 5.4.0-1082.87 USN-7088-1
Ubuntu 20.04 LTS linux-ibm-5.15 5.15.0-1065.68~20.04.1 USN-7100-1
Ubuntu 20.04 LTS linux-intel-iotg-5.15 5.15.0-1067.73~20.04.1 USN-7144-1
Ubuntu 20.04 LTS linux-iot 5.4.0-1044.45 USN-7119-1
Ubuntu 20.04 LTS linux-kvm 5.4.0-1123.131 USN-7088-4
Ubuntu 20.04 LTS linux-nvidia-tegra-5.15 5.15.0-1032.32~20.04.1 —
Ubuntu 20.04 LTS linux-oracle 5.4.0-1134.143 USN-7088-4
Ubuntu 20.04 LTS linux-oracle-5.15 5.15.0-1070.76~20.04.1 USN-7100-1
Ubuntu 20.04 LTS linux-raspi 5.4.0-1119.131 USN-7088-5
Ubuntu 20.04 LTS linux-riscv-5.15 5.15.0-1068.72~20.04.1 —
Ubuntu 20.04 LTS linux-xilinx-zynqmp 5.4.0-1054.58 USN-7088-4
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Show 15 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 16.04 LTS linux-hwe-edge No fix yet —
Ubuntu Pro Realtime 24.04 LTS linux-raspi-realtime 6.8.0-2015.16 —
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1013.14 —
Ubuntu Pro Realtime 22.04 LTS linux-intel-iot-realtime 5.15.0-1066.68 —
Ubuntu Pro Realtime 22.04 LTS linux-realtime 5.15.0-1073.81 —
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1013.14~22.04.1 —
Ubuntu Pro FIPS 20.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS 16.04 LTS linux-fips No fix yet —
Ubuntu Pro FIPS-updates 24.04 LTS linux-fips 6.8.0-78.78+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-aws-fips 5.15.0-1072.78+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-azure-fips 5.15.0-1075.84+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips 5.15.0-125.135+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-gcp-fips 5.15.0-1071.79+fips1 —
Ubuntu Pro FIPS-updates 20.04 LTS linux-aws-fips 5.4.0-1135.145+fips1 —
Ubuntu Pro FIPS-updates 20.04 LTS linux-azure-fips 5.4.0-1140.147+fips1 —
Ubuntu Pro FIPS-updates 20.04 LTS linux-fips 5.4.0-1109.119 —
Ubuntu Pro FIPS-updates 20.04 LTS linux-gcp-fips 5.4.0-1139.148+fips1 —
Ubuntu Pro FIPS-updates 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-updates 16.04 LTS linux-fips No fix yet —
Ubuntu Pro FIPS-preview 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro 18.04 LTS linux +5 No fix yet —
Ubuntu Pro 18.04 LTS linux-aws-5.4 5.4.0-1135.145~18.04.1 USN-7088-3
Ubuntu Pro 18.04 LTS linux-azure-5.4 5.4.0-1140.147~18.04.1 USN-7088-4
Ubuntu Pro 18.04 LTS linux-gcp-5.4 5.4.0-1139.148~18.04.1 USN-7088-1
Ubuntu Pro 18.04 LTS linux-hwe-5.4 5.4.0-200.220~18.04.1 USN-7088-1
Ubuntu Pro 18.04 LTS linux-ibm-5.4 5.4.0-1082.87~18.04.1 USN-7088-1
Ubuntu Pro 18.04 LTS linux-oracle-5.4 5.4.0-1134.143~18.04.1 USN-7088-3
Ubuntu Pro 18.04 LTS linux-raspi-5.4 5.4.0-1119.131~18.04.1 USN-7088-5
Ubuntu Pro 16.04 LTS linux +7 No fix yet —
Ubuntu Pro 14.04 LTS linux +3 No fix yet —
ReleasePackageFixed inAdvisory
RHEL 9 rv +77 5.14.0-570.12.1.el9_6 RHSA-2025:6966
ReleasePackageFixed inAdvisory
SLES 15 SP6 kernel-64kb +4 6.4.0-150600.23.25.1 SUSE-SU-2024:3561-1
SLES 15 SP6 kernel-azure +2 6.4.0-150600.8.14.1 SUSE-SU-2024:3551-1
SLES 15 SP6 kernel-default-base 6.4.0-150600.23.25.1.150600.12.10.2 SUSE-SU-2024:3561-1
SLES 15 SP6 kernel-docs +1 6.4.0-150600.23.25.2 SUSE-SU-2024:3561-1
SLES 15 SP5 kernel-64kb +6 5.14.21-150500.55.83.1 SUSE-SU-2024:3569-1
SLES 15 SP5 kernel-azure +2 5.14.21-150500.33.69.1 SUSE-SU-2024:3587-1
SLES 15 SP5 kernel-default-base 5.14.21-150500.55.83.1.150500.6.37.1 SUSE-SU-2024:3569-1
SLES 12 SP5 kernel-azure +2 4.12.14-16.200.1 SUSE-SU-2024:3591-1
SLES 12 SP5 kernel-docs +4 4.12.14-122.231.1 SUSE-SU-2024:3559-1
Show 9 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 12 SP5 kernel-azure +2 4.12.14-16.200.1 SUSE-SU-2024:3591-1
SLES for SAP 12 SP5 kernel-syms +2 4.12.14-122.231.1 SUSE-SU-2024:3559-1
SLE Real Time 12 SP5 kernel-rt +3 4.12.14-10.203.1 SUSE-SU-2024:3566-1
SLE Micro 6.0 kernel-default-base 6.4.0-17.1.1.51 SUSE-SU-2025:20073-1
SLE Micro 6.0 kernel-livepatch-MICRO-6-0_Update_3 +1 1-1.2 SUSE-SU-2025:20077-1, SUSE-SU-2025:20073-1
SLE Micro 6.0 kernel-rt +1 6.4.0-11.1 SUSE-SU-2025:20077-1
SLE Micro 6.0 kernel-source +2 6.4.0-20.1 SUSE-SU-2025:20073-1
SLE Micro 5.5 kernel-default 5.14.21-150500.55.83.1 SUSE-SU-2024:3569-1
SLE Micro 5.5 kernel-default-base 5.14.21-150500.55.83.1.150500.6.37.1 SUSE-SU-2024:3569-1
SLE Micro 5.5 kernel-rt +1 5.14.21-150500.13.73.1 SUSE-SU-2024:3592-1
SLE Live Patching 15 SP6 kernel-default 6.4.0-150600.23.25.1 SUSE-SU-2024:3561-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6-RT_Update_4 1-150600.1.3.1 SUSE-SU-2024:3564-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_5 1-150600.13.3.1 SUSE-SU-2024:3561-1
SLE Live Patching 15 SP5 kernel-default 5.14.21-150500.55.83.1 SUSE-SU-2024:3569-1
SLE Live Patching 15 SP5 kernel-livepatch-SLE15-SP5_Update_20 +1 1-150500.11.3.1 SUSE-SU-2024:3592-1, SUSE-SU-2024:3569-1
SLE Live Patching 12 SP5 kernel-default 4.12.14-122.231.1 SUSE-SU-2024:3559-1
SLE Live Patching 12 SP5 kgraft-patch-SLE12-SP5_Update_61 1-8.3.1 SUSE-SU-2024:3559-1
SUSE Real Time Module 15 SP6 kernel-rt +3 6.4.0-150600.10.14.1 SUSE-SU-2024:3564-1
SUSE Real Time Module 15 SP5 kernel-rt +3 5.14.21-150500.13.73.1 SUSE-SU-2024:3592-1
ReleasePackageFixed inAdvisory
openSUSE Leap 15.6 dtb-aarch64 +8 6.4.0-150600.23.25.1 SUSE-SU-2024:3561-1
openSUSE Leap 15.6 kernel-azure +2 6.4.0-150600.8.14.1 SUSE-SU-2024:3551-1
openSUSE Leap 15.6 kernel-default-base 6.4.0-150600.23.25.1.150600.12.10.2 SUSE-SU-2024:3561-1
openSUSE Leap 15.6 kernel-docs +1 6.4.0-150600.23.25.2 SUSE-SU-2024:3561-1
openSUSE Leap 15.6 kernel-rt +3 6.4.0-150600.10.14.1 SUSE-SU-2024:3564-1
openSUSE Leap 15.5 kernel-azure +2 5.14.21-150500.33.69.1 SUSE-SU-2024:3587-1
openSUSE Leap 15.5 kernel-rt +3 5.14.21-150500.13.73.1 SUSE-SU-2024:3592-1
Show 1 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
openSUSE Leap Micro 5.5 kernel-default 5.14.21-150500.55.83.1 SUSE-SU-2024:3569-1
openSUSE Leap Micro 5.5 kernel-default-base 5.14.21-150500.55.83.1.150500.6.37.1 SUSE-SU-2024:3569-1
openSUSE Leap Micro 5.5 kernel-rt 5.14.21-150500.13.73.1 SUSE-SU-2024:3592-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 kernel-livepatch-6.1.106-116.188 1.0-0.amzn2023 ALAS2023-2025-864
Amazon Linux 2023 perf +14 6.1.106-116.188.amzn2023 ALAS2023-2025-864
Amazon Linux 2 kernel-livepatch-4.14.353-270.569 1.0-0.amzn2 ALAS2-2025-2777
Amazon Linux 2 perf +8 4.14.353-270.569.amzn2 ALAS2-2025-2777

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 9 bpftool 7.5.0-802.el9_6 ELSA-2025-6966
Oracle Linux 9 rv +28 5.14.0-570.12.1.0.1.el9_6 ELSA-2025-6966
Oracle Linux 8 bpftool +13 5.15.0-302.167.6.el9uek ELSA-2024-12815
Oracle Linux 7 kernel-uek-container +1 5.4.17-2136.336.5.1.el8uek ELSA-2024-12782
Oracle Linux 7 perf +10 4.14.35-2047.543.3.el7uek ELSA-2024-12868, ELSA-2024-12780

Advisories 40

References