CVSS: -EPSS: 0%CPEs: 6EXPL: 0CVE-2024-50115 – KVM: nSVM: Ignore nCR3[4:0] when loading PDPTEs from memory
https://notcve.org/view.php?id=CVE-2024-50115
In the Linux kernel, the following vulnerability has been resolved: KVM: nSVM: Ignore nCR3[4:0] when loading PDPTEs from memory Ignore nCR3[4:0] when loading PDPTEs from memory for nested SVM, as bits 4:0 of CR3 are ignored when PAE paging is used, and thus VMRUN doesn't enforce 32-byte alignment of nCR3. In the absolute worst case scenario, failure to ignore bits 4:0 can result in an out-of-bounds read, e.g. if the target page is at the end of a memslot, and the VMM isn't using guard pages. Per the APM: The CR3 register points to the base address of the page-directory-pointer table. The page-directory-pointer table is aligned on a 32-byte boundary, with the low 5 address bits 4:0 assumed to be 0. And the SDM's much more explicit: 4:0 Ignored Note, KVM gets this right when loading PDPTRs, it's only the nSVM flow that is broken. En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: KVM: nSVM: Ignorar nCR3[4:0] al cargar PDPTE desde la memoria Ignorar nCR3[4:0] al cargar PDPTE desde la memoria para SVM anidado, ya que los bits 4:0 de CR3 se ignoran cuando se utiliza la paginación PAE y, por lo tanto, VMRUN no aplica la alineación de 32 bytes de nCR3. En el peor de los casos, no ignorar los bits 4:0 puede dar como resultado una lectura fuera de los límites, por ejemplo, si la página de destino está al final de un memslot y el VMM no está utilizando páginas de protección. Según el APM: El registro CR3 apunta a la dirección base de la tabla de punteros de directorio de páginas. • https://git.kernel.org/stable/c/e4e517b4be019787ada4cbbce2f04570c21b0cbd https://git.kernel.org/stable/c/76ce386feb14ec9a460784fcd495d8432acce7a5 https://git.kernel.org/stable/c/58cb697d80e669c56197f703e188867c8c54c494 https://git.kernel.org/stable/c/6876793907cbe19d42e9edc8c3315a21e06c32ae https://git.kernel.org/stable/c/2c4adc9b192a0815fe58a62bc0709449416cc884 https://git.kernel.org/stable/c/426682afec71ea3f889b972d038238807b9443e4 https://git.kernel.org/stable/c/f559b2e9c5c5308850544ab59396b7d53cfc67bd •
CVSS: -EPSS: 0%CPEs: 3EXPL: 0CVE-2024-50112 – x86/lam: Disable ADDRESS_MASKING in most cases
https://notcve.org/view.php?id=CVE-2024-50112
In the Linux kernel, the following vulnerability has been resolved: x86/lam: Disable ADDRESS_MASKING in most cases Linear Address Masking (LAM) has a weakness related to transient execution as described in the SLAM paper[1]. Unless Linear Address Space Separation (LASS) is enabled this weakness may be exploitable. Until kernel adds support for LASS[2], only allow LAM for COMPILE_TEST, or when speculation mitigations have been disabled at compile time, otherwise keep LAM disabled. There are no processors in market that support LAM yet, so currently nobody is affected by this issue. [1] SLAM: https://download.vusec.net/papers/slam_sp24.pdf [2] LASS: https://lore.kernel.org/lkml/20230609183632.48706-1-alexander.shishkin@linux.intel.com/ [ dhansen: update SPECULATION_MITIGATIONS -> CPU_MITIGATIONS ] En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: x86/lam: Deshabilitar ADDRESS_MASKING en la mayoría de los casos. El enmascaramiento de direcciones lineales (LAM) tiene una debilidad relacionada con la ejecución transitoria como se describe en el documento SLAM[1]. A menos que se habilite la separación del espacio de direcciones lineales (LASS), esta debilidad puede ser explotable. Hasta que el kernel agregue soporte para LASS[2], solo permita LAM para COMPILE_TEST, o cuando las mitigaciones de especulación se hayan deshabilitado en el momento de la compilación, de lo contrario, mantenga LAM deshabilitado. • https://git.kernel.org/stable/c/60a5ba560f296ad8da153f6ad3f70030bfa3958f https://git.kernel.org/stable/c/690599066488d16db96ac0d6340f9372fc56f337 https://git.kernel.org/stable/c/3267cb6d3a174ff83d6287dcd5b0047bbd912452 •
CVSS: -EPSS: 0%CPEs: 4EXPL: 0CVE-2024-50108 – drm/amd/display: Disable PSR-SU on Parade 08-01 TCON too
https://notcve.org/view.php?id=CVE-2024-50108
In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Disable PSR-SU on Parade 08-01 TCON too Stuart Hayhurst has found that both at bootup and fullscreen VA-API video is leading to black screens for around 1 second and kernel WARNING [1] traces when calling dmub_psr_enable() with Parade 08-01 TCON. These symptoms all go away with PSR-SU disabled for this TCON, so disable it for now while DMUB traces [2] from the failure can be analyzed and the failure state properly root caused. (cherry picked from commit afb634a6823d8d9db23c5fb04f79c5549349628b) En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: drm/amd/display: Deshabilitar PSR-SU también en Parade 08-01 TCON Stuart Hayhurst ha descubierto que tanto en el arranque como en pantalla completa, el vídeo VA-API provoca pantallas negras durante alrededor de 1 segundo y rastros de ADVERTENCIA [1] en el kernel al llamar a dmub_psr_enable() con Parade 08-01 TCON. Todos estos síntomas desaparecen con PSR-SU deshabilitado para este TCON, así que deshabilítelo por ahora mientras se pueden analizar los rastros DMUB [2] del fallo y se puede determinar correctamente el estado del fallo. (seleccionado de la confirmación afb634a6823d8d9db23c5fb04f79c5549349628b) • https://git.kernel.org/stable/c/5660bcc4dd533005248577d5042f1c48cce2b443 https://git.kernel.org/stable/c/c79e0a18e4b301401bb745702830be9041cfbf04 https://git.kernel.org/stable/c/fc6afa07b5e251148fb37600ee06e1a7007178c3 https://git.kernel.org/stable/c/ba1959f71117b27f3099ee789e0815360b4081dd •
CVSS: -EPSS: 0%CPEs: 2EXPL: 0CVE-2024-50106 – nfsd: fix race between laundromat and free_stateid
https://notcve.org/view.php?id=CVE-2024-50106
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix race between laundromat and free_stateid There is a race between laundromat handling of revoked delegations and a client sending free_stateid operation. Laundromat thread finds that delegation has expired and needs to be revoked so it marks the delegation stid revoked and it puts it on a reaper list but then it unlock the state lock and the actual delegation revocation happens without the lock. Once the stid is marked revoked a racing free_stateid processing thread does the following (1) it calls list_del_init() which removes it from the reaper list and (2) frees the delegation stid structure. The laundromat thread ends up not calling the revoke_delegation() function for this particular delegation but that means it will no release the lock lease that exists on the file. Now, a new open for this file comes in and ends up finding that lease list isn't empty and calls nfsd_breaker_owns_lease() which ends up trying to derefence a freed delegation stateid. Leading to the followint use-after-free KASAN warning: kernel: ================================================================== kernel: BUG: KASAN: slab-use-after-free in nfsd_breaker_owns_lease+0x140/0x160 [nfsd] kernel: Read of size 8 at addr ffff0000e73cd0c8 by task nfsd/6205 kernel: kernel: CPU: 2 UID: 0 PID: 6205 Comm: nfsd Kdump: loaded Not tainted 6.11.0-rc7+ #9 kernel: Hardware name: Apple Inc. • https://git.kernel.org/stable/c/2d4a532d385f635ab8243b88db3136bb52a0bc29 https://git.kernel.org/stable/c/967faa26f313a62e7bebc55d5b8122eaee43b929 https://git.kernel.org/stable/c/8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a •
CVSS: -EPSS: 0%CPEs: 8EXPL: 0CVE-2024-50099 – arm64: probes: Remove broken LDR (literal) uprobe support
https://notcve.org/view.php?id=CVE-2024-50099
In the Linux kernel, the following vulnerability has been resolved: arm64: probes: Remove broken LDR (literal) uprobe support The simulate_ldr_literal() and simulate_ldrsw_literal() functions are unsafe to use for uprobes. Both functions were originally written for use with kprobes, and access memory with plain C accesses. When uprobes was added, these were reused unmodified even though they cannot safely access user memory. There are three key problems: 1) The plain C accesses do not have corresponding extable entries, and thus if they encounter a fault the kernel will treat these as unintentional accesses to user memory, resulting in a BUG() which will kill the kernel thread, and likely lead to further issues (e.g. lockup or panic()). 2) The plain C accesses are subject to HW PAN and SW PAN, and so when either is in use, any attempt to simulate an access to user memory will fault. Thus neither simulate_ldr_literal() nor simulate_ldrsw_literal() can do anything useful when simulating a user instruction on any system with HW PAN or SW PAN. 3) The plain C accesses are privileged, as they run in kernel context, and in practice can access a small range of kernel virtual addresses. The instructions they simulate have a range of +/-1MiB, and since the simulated instructions must itself be a user instructions in the TTBR0 address range, these can address the final 1MiB of the TTBR1 acddress range by wrapping downwards from an address in the first 1MiB of the TTBR0 address range. In contemporary kernels the last 8MiB of TTBR1 address range is reserved, and accesses to this will always fault, meaning this is no worse than (1). Historically, it was theoretically possible for the linear map or vmemmap to spill into the final 8MiB of the TTBR1 address range, but in practice this is extremely unlikely to occur as this would require either: * Having enough physical memory to fill the entire linear map all the way to the final 1MiB of the TTBR1 address range. * Getting unlucky with KASLR randomization of the linear map such that the populated region happens to overlap with the last 1MiB of the TTBR address range. ... and in either case if we were to spill into the final page there would be larger problems as the final page would alias with error pointers. Practically speaking, (1) and (2) are the big issues. Given there have been no reports of problems since the broken code was introduced, it appears that no-one is relying on probing these instructions with uprobes. Avoid these issues by not allowing uprobes on LDR (literal) and LDRSW (literal), limiting the use of simulate_ldr_literal() and simulate_ldrsw_literal() to kprobes. • https://git.kernel.org/stable/c/9842ceae9fa8deae141533d52a6ead7666962c09 https://git.kernel.org/stable/c/cc86f2e9876c8b5300238cec6bf0bd8c842078ee https://git.kernel.org/stable/c/ae743deca78d9e4b7f4f60ad2f95e20e8ea057f9 https://git.kernel.org/stable/c/3728b4eb27910ffedd173018279a970705f2e03a https://git.kernel.org/stable/c/ad4bc35a6d22e9ff9b67d0d0c38bce654232f195 https://git.kernel.org/stable/c/bae792617a7e911477f67a3aff850ad4ddf51572 https://git.kernel.org/stable/c/9f1e7735474e7457a4d919a517900e46868ae5f6 https://git.kernel.org/stable/c/20cde998315a3d2df08e26079a3ea7501 •