kernel: Mishandling of indirect calls weakens Spectre mitigation for paravirtual guests

arch/x86/kernel/paravirt.c in the Linux kernel before 4.18.1 mishandles certain indirect calls, which makes it easier for attackers to conduct Spectre-v2 attacks against paravirtual guests.

Kernel: hw: cpu: userspace-userspace spectreRSB attack

The spectre_v2_select_mitigation function in arch/x86/kernel/cpu/bugs.c in the Linux kernel before 4.18.1 does not always fill RSB upon a context switch, which makes it easier for attackers to conduct userspace-userspace spectreRSB attacks.

kernel: net: xen: Linux netback driver OOB access in hash handling (XSA-270)

An issue was discovered in xenvif_set_hash_mapping in drivers/net/xen-netback/hash.c in the Linux kernel through 4.18.1, as used in Xen through 4.11.x and other products. The Linux netback driver allows frontends to control mapping of requests to request queues. When processing a request to set or change this mapping, some input validation (e.g., for an integer overflow) was missing or flawed, leading to OOB access in hash handling. A malicious or buggy frontend may cause the (usually privileged) backend to make out of bounds memory accesses, potentially resulting in one or more of privilege escalation, Denial of Service (DoS), or information leaks.

The svpn component of the F5 BIG-IP APM client prior to version 7.1.7.2 for Linux and macOS runs as a privileged process and can allow an unprivileged user to get ownership of files owned by root on the local client host in a race condition.

An Information Exposure issue was discovered in Hitachi Command Suite 8.5.3. A remote attacker may be able to exploit a flaw in the permission of messaging that may allow for information exposure via a crafted message.

kernel: use-after-free in ucma_leave_multicast in drivers/infiniband/core/ucma.c

drivers/infiniband/core/ucma.c in the Linux kernel through 4.17.11 allows ucma_leave_multicast to access a certain data structure after a cleanup step in ucma_process_join, which allows attackers to cause a denial of service (use-after-free).

xen: Uninitialized state in x86 PV failsafe callback path (XSA-274)

An issue was discovered in the Linux kernel through 4.17.11, as used in Xen through 4.11.x. The xen_failsafe_callback entry point in arch/x86/entry/entry_64.S does not properly maintain RBX, which allows local users to cause a denial of service (uninitialized memory usage and system crash). Within Xen, 64-bit x86 PV Linux guest OS users can trigger a guest OS crash or possibly gain privileges.

kernel: Arbitrary Kernel Read into dmesg via Missing Address Check in segfault Handler

A missing address check in the callers of the show_opcodes() in the Linux kernel allows an attacker to dump the kernel memory at an arbitrary kernel address into the dmesg log.

kernel: NULL pointer dereference in af_netlink.c:__netlink_ns_capable() allows for denial of service

The Linux kernel before 4.15-rc8 was found to be vulnerable to a NULL pointer dereference bug in the __netlink_ns_capable() function in the net/netlink/af_netlink.c file. A local attacker could exploit this when a net namespace with a netnsid is assigned to cause a kernel panic and a denial of service.

kernel: a bug in ip_frag_reasm() can cause a crash in ip_do_fragment()

A security flaw was found in the ip_frag_reasm() function in net/ipv4/ip_fragment.c in the Linux kernel from 4.19-rc1 to 4.19-rc3 inclusive, which can cause a later system crash in ip_do_fragment(). With certain non-default, but non-rare, configuration of a victim host, an attacker can trigger this crash remotely, thus leading to a remote denial-of-service.

kernel: stack-based buffer overflow in chap_server_compute_md5() in iscsi target

A security flaw was found in the chap_server_compute_md5() function in the ISCSI target code in the Linux kernel in a way an authentication request from an ISCSI initiator is processed. An unauthenticated remote attacker can cause a stack buffer overflow and smash up to 17 bytes of the stack. The attack requires the iSCSI target to be enabled on the victim host. Depending on how the target's code was built (i.e. depending on a compiler, compile flags and hardware architecture) an attack may lead to a system crash and thus to a denial-of-service or possibly to a non-authorized access to data exported by an iSCSI target. Due to the nature of the flaw, privilege escalation cannot be fully ruled out, although we believe it is highly unlikely. Kernel versions 4.18.x, 4.14.x and 3.10.x are believed to be vulnerable.

kernel: use-after-free Read in vhost_transport_send_pkt

A flaw was found in the Linux Kernel where an attacker may be able to have an uncontrolled read to kernel-memory from within a vm guest. A race condition between connect() and close() function may allow an attacker using the AF_VSOCK protocol to gather a 4 byte information leak or possibly intercept or corrupt AF_VSOCK messages destined to other clients.

kernel: crash (possible privesc) in kernel crypto api.

A flaw was found in the crypto subsystem of the Linux kernel before version kernel-4.15-rc4. The "null skcipher" was being dropped when each af_alg_ctx was freed instead of when the aead_tfm was freed. This can cause the null skcipher to be freed while it is still in use leading to a local user being able to crash the system or possibly escalate privileges.

kernel: NULL pointer dereference in fs/hfsplus/dir.c:hfsplus_lookup() when operating on a file in a crafted hfs+ image

An issue was discovered in the Linux kernel through 4.17.10. There is a NULL pointer dereference and panic in hfsplus_lookup() in fs/hfsplus/dir.c when opening a file (that is purportedly a hard link) in an hfs+ filesystem that has malformed catalog data, and is mounted read-only without a metadata directory.

kernel: NULL pointer dereference in fs/crypto/crypto.c:fscrypt_do_page_crypto() when operating on a corrupted f2fs image

An issue was discovered in the Linux kernel through 4.17.10. There is a NULL pointer dereference in fscrypt_do_page_crypto() in fs/crypto/crypto.c when operating on a file in a corrupted f2fs image.

kernel: Buffer overflow in fs/f2fs/inline.c:truncate_inline_inode() when unmounting a crafted f2fs image

An issue was discovered in the Linux kernel through 4.17.10. There is a buffer overflow in truncate_inline_inode() in fs/f2fs/inline.c when umounting an f2fs image, because a length value may be negative.

kernel: Out-of-bounds access in fs/f2fs/segment.c:__remove_dirty_segment() when mounting a crafted f2fs image

An issue was discovered in the Linux kernel through 4.17.10. There is an out-of-bounds access in __remove_dirty_segment() in fs/f2fs/segment.c when mounting an f2fs image.

kernel: Invalid pointer dereference in io_ctl_map_page() when mounting and operating a crafted btrfs image

An issue was discovered in the Linux kernel through 4.17.10. There is an invalid pointer dereference in io_ctl_map_page() when mounting and operating a crafted btrfs image, because of a lack of block group item validation in check_leaf_item in fs/btrfs/tree-checker.c.

kernel: Invalid pointer dereference in btrfs_root_node() when mounting a crafted btrfs image

An issue was discovered in the Linux kernel through 4.17.10. There is an invalid pointer dereference in btrfs_root_node() when mounting a crafted btrfs image, because of a lack of chunk block group mapping validation in btrfs_read_block_groups in fs/btrfs/extent-tree.c, and a lack of empty-tree checks in check_leaf in fs/btrfs/tree-checker.c.

kernel: Use-after-free in try_merge_free_space() when mounting crafted btrfs image

An issue was discovered in the Linux kernel through 4.17.10. There is a use-after-free in try_merge_free_space() when mounting a crafted btrfs image, because of a lack of chunk type flag checks in btrfs_check_chunk_valid in fs/btrfs/volumes.c.