CVE-2024-35872 — mm/secretmem: fix GUP-fast succeeding on secretmem folios

Affected: Linux

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

mm/secretmem: fix GUP-fast succeeding on secretmem folios

folio_is_secretmem() currently relies on secretmem folios being LRU folios, to save some cycles.

However, folios might reside in a folio batch without the LRU flag set, or temporarily have their LRU flag cleared. Consequently, the LRU flag is unreliable for this purpose.

In particular, this is the case when secretmem_fault() allocates a fresh page and calls filemap_add_folio()->folio_add_lru(). The folio might be added to the per-cpu folio batch and won't get the LRU flag set until the batch was drained using e.g., lru_add_drain().

Consequently, folio_is_secretmem() might not detect secretmem folios and GUP-fast can succeed in grabbing a secretmem folio, crashing the kernel when we would later try reading/writing to the folio, because the folio has been unmapped from the directmap.

Fix it by removing that unreliable check.

USN-6893-1 — linux, linux-azure, linux-gcp, linux-ibm, linux-intel, linux-lowlatency, linux-oem-6.8, linux-raspi vulnerabilities

Affected: Ubuntu:24.04:LTS: linux, Ubuntu:24.04:LTS: linux-azure, Ubuntu:24.04:LTS: linux-gcp, Ubuntu:24.04:LTS: linux-ibm, Ubuntu:24.04:LTS: linux-intel, Ubuntu:24.04:LTS: linux-lowlatency, Ubuntu:24.04:LTS: linux-oem-6.8, Ubuntu:24.04:LTS: linux-raspi

It was discovered that a race condition existed in the Bluetooth subsystem in the Linux kernel when modifying certain settings values through debugfs. A privileged local attacker could use this to cause a denial of service. (CVE-2024-24857, CVE-2024-24858, CVE-2024-24859)

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; - RISC-V architecture; - S390 architecture; - x86 architecture; - Block layer subsystem; - Compute Acceleration Framework; - Accessibility subsystem; - Android drivers; - Drivers core; - Bluetooth drivers; - Clock framework and drivers; - Data acquisition framework and drivers; - Cryptographic API; - Buffer Sharing and Synchronization framework; - GPU drivers; - On-Chip Interconnect management framework; - IOMMU subsystem; - Multiple devices driver; - Media drivers; - VMware VMCI Driver; - Network drivers; - Microsoft Azure Network Adapter (MANA) driver; - Device tree and open firmware driver; - Chrome hardware platform drivers; - i.MX PM domains; - TI SCI PM domains driver; - S/390 drivers; - SCSI drivers; - SPI subsystem; - Thermal drivers; - TTY drivers; - USB subsystem; - Framebuffer layer; - BTRFS file system; - Network file system server daemon; - NILFS2 file system; - File systems infrastructure; - Pstore file system; - SMB…

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CVE-2024-35872 — mm/secretmem: fix GUP-fast succeeding on secretmem folios

USN-6893-1 — linux, linux-azure, linux-gcp, linux-ibm, linux-intel, linux-lowlatency, linux-oem-6.8, linux-raspi vulnerabilities