CVE-2024-42305 — ext4: check dot and dotdot of dx_root before making dir indexed

Affected: Linux, Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem

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-------------|.......…

USN-7088-1 — linux, linux-gcp, linux-gcp-5.4, linux-gkeop, linux-hwe-5.4, linux-ibm, linux-ibm-5.4 vulnerabilities

Affected: Ubuntu:Pro:18.04:LTS: linux-gcp-5.4, Ubuntu:Pro:18.04:LTS: linux-hwe-5.4, Ubuntu:Pro:18.04:LTS: linux-ibm-5.4, Ubuntu:20.04:LTS: linux, Ubuntu:20.04:LTS: linux-gcp, Ubuntu:20.04:LTS: linux-gkeop, Ubuntu:20.04:LTS: linux-ibm

Ziming Zhang discovered that the VMware Virtual GPU DRM driver in the Linux kernel contained an integer overflow vulnerability. A local attacker could use this to cause a denial of service (system crash). (CVE-2022-36402)

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - ARM64 architecture; - PowerPC architecture; - User-Mode Linux (UML); - x86 architecture; - Block layer subsystem; - Cryptographic API; - Android drivers; - Serial ATA and Parallel ATA drivers; - ATM drivers; - Drivers core; - CPU frequency scaling framework; - Device frequency scaling framework; - GPU drivers; - HID subsystem; - Hardware monitoring drivers; - InfiniBand drivers; - Input Device core drivers; - IOMMU subsystem; - IRQ chip drivers; - ISDN/mISDN subsystem; - LED subsystem; - Multiple devices driver; - Media drivers; - EEPROM drivers; - VMware VMCI Driver; - MMC subsystem; - Network drivers; - Near Field Communication (NFC) drivers; - NVME drivers; - Device tree and open firmware driver; - Parport drivers; - PCI subsystem; - Pin controllers subsystem; - Remote Processor subsystem; - S/390 drivers; - SCSI drivers; - QCOM SoC drivers; - Direct Digital Synthesis drivers; - TTY drivers; - Userspace I/O drivers; - DesignWare USB3 driver; - USB subsystem; - BTRFS file system; - File sy…

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CVE-2024-42305 — ext4: check dot and dotdot of dx_root before making dir indexed

USN-7088-1 — linux, linux-gcp, linux-gcp-5.4, linux-gkeop, linux-hwe-5.4, linux-ibm, linux-ibm-5.4 vulnerabilities