CVE-2018-1093

La función ext4_valid_block_bitmap en fs/ext4/balloc.c en el kernel de Linux hasta la versión 4.15.15 permite que los atacantes provoquen un denegación de servicio (lectura fuera de límites y cierre inesperado del sistema) mediante una imagen ext4 manipulada dado que balloc.c y ialloc.c no validan los números de los bloques de mapa de bits.

Alexei Starovoitov discovered that the Berkeley Packet Filter (BPF) implementation in the Linux kernel contained a branch-pruning logic issue around unreachable code. A local attacker could use this to cause a denial of service. The ext4_iget function in fs/ext4/inode.c in the Linux kernel through 4.15.15 mishandles the case of a root directory with a zero i_links_count, which allows attackers to cause a denial of service (ext4_process_freed_data NULL pointer dereference and OOPS) via a crafted ext4 image. Various other issues were also addressed.