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.
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Ubuntu Security Notice 3523-3 - Jann Horn discovered that the Berkeley Packet Filter implementation in the Linux kernel did not properly check the relationship between pointer values and the BPF stack. A local attacker could use this to cause a denial of service or possibly execute arbitrary code. Jann Horn discovered that the Berkeley Packet Filter implementation in the Linux kernel improperly performed sign extension in some situations. A local attacker could use this to cause a denial of service or possibly execute arbitrary code. Various other issues were also addressed.
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Ubuntu Security Notice 3532-2 - USN-3523-1 fixed vulnerabilities in the Linux kernel for Ubuntu 17.10. This update provides the corresponding updates for the Linux Hardware Enablement kernel from Ubuntu 17.10 for Ubuntu 16.04 LTS. Jann Horn discovered that microprocessors utilizing speculative execution and indirect branch prediction may allow unauthorized memory reads via sidechannel attacks. This flaw is known as Meltdown. A local attacker could use this to expose sensitive information, including kernel memory. Various other issues were also addressed.
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Ubuntu Security Notice 3523-1 - Jann Horn discovered that microprocessors utilizing speculative execution and indirect branch prediction may allow unauthorized memory reads via sidechannel attacks. This flaw is known as Meltdown. A local attacker could use this to expose sensitive information, including kernel memory. Jann Horn discovered that the Berkeley Packet Filter implementation in the Linux kernel did not properly check the relationship between pointer values and the BPF stack. A local attacker could use this to cause a denial of service or possibly execute arbitrary code. Various other issues were also addressed.
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