pf incorrectly matches different ICMPv6 states in the state table

In ICMPv6 Neighbor Discovery (ND), the ID is always 0. When pf is configured to allow ND and block incoming Echo Requests, a crafted Echo Request packet after a Neighbor Solicitation (NS) can trigger an Echo Reply. The packet has to come from the same host as the NS and have a zero as identifier to match the state created by the Neighbor Discovery and allow replies to be generated. ICMPv6 packets with identifier value of zero bypass firewall rules written on the assumption that the incoming packets are going to create a state in the state table.

bhyve(8) virtio_vq_recordon time-of-check to time-of-use race

The virtio_vq_recordon function is subject to a time-of-check to time-of-use (TOCTOU) race condition.

Multiple vulnerabilities in libnv

A missing null-termination character in the last element of an nvlist array string can lead to writing outside the allocated buffer.

Unbounded allocation in ctl(4) CAM Target Layer

The command ctl_persistent_reserve_out allows the caller to specify an arbitrary size which will be passed to the kernel's memory allocator.

bhyve(8) out-of-bounds read access via XHCI emulation

An insufficient boundary validation in the USB code could lead to an out-of-bounds read on the heap, which could potentially lead to an arbitrary write and remote code execution.

bhyve(8) nvme_opc_get_log_page buffer over-read

The NVMe driver function nvme_opc_get_log_page is vulnerable to a buffer over-read from a guest-controlled value.

Buffer overflow in some filesystems via NFS

On 64-bit systems, the implementation of VOP_VPTOFH() in the cd9660, tarfs and ext2fs filesystems overflows the destination FID buffer by 4 bytes, a stack buffer overflow. A NFS server that exports a cd9660, tarfs, or ext2fs file system can be made to panic by mounting and accessing the export with an NFS client. Further exploitation (e.g., bypassing file permission checking or remote kernel code execution) is potentially possible, though this has not been demonstrated. In particular, release kernels are compiled with stack protection enabled, and some instances of the overflow are caught by this mechanism, causing a panic.

Unprivileged access to system files

When etcupdate encounters conflicts while merging files, it saves a version containing conflict markers in /var/db/etcupdate/conflicts. This version does not preserve the mode of the input file, and is world-readable. This applies to files that would normally have restricted visibility, such as /etc/master.passwd. An unprivileged local user may be able to read encrypted root and user passwords from the temporary master.passwd file created in /var/db/etcupdate/conflicts. This is possible only when conflicts within the password file arise during an update, and the unprotected file is deleted when conflicts are resolved.

Uninitialized kernel memory disclosure via ktrace(2)

In some cases, the ktrace facility will log the contents of kernel structures to userspace. In one such case, ktrace dumps a variable-sized sockaddr to userspace. There, the full sockaddr is copied, even when it is shorter than the full size. This can result in up to 14 uninitialized bytes of kernel memory being copied out to userspace. It is possible for an unprivileged userspace program to leak 14 bytes of a kernel heap allocation to userspace.

pf silently ignores certain rules

A regression in the way hashes were calculated caused rules containing the address range syntax (x.x.x.x - y.y.y.y) that only differ in the address range(s) involved to be silently dropped as duplicates. Only the first of such rules is actually loaded into pf. Ranges expressed using the address[/mask-bits] syntax were not affected. Some keywords representing actions taken on a packet-matching rule, such as 'log', 'return tll', or 'dnpipe', may suffer from the same issue. It is unlikely that users have such configurations, as these rules would always be redundant. Affected rules are silently ignored, which can lead to unexpected behaviour including over- and underblocking.

Remote code execution via ND6 Router Advertisements

The rtsol(8) and rtsold(8) programs do not validate the domain search list options provided in router advertisement messages; the option body is passed to resolvconf(8) unmodified. resolvconf(8) is a shell script which does not validate its input. A lack of quoting meant that shell commands pass as input to resolvconf(8) may be executed.

ipfw denial of service

In some cases, the `tcp-setmss` handler may free the packet data and throw an error without halting the rule processing engine. A subsequent rule can then allow the traffic after the packet data is gone, resulting in a NULL pointer dereference. Maliciously crafted packets sent from a remote host may result in a Denial of Service (DoS) if the `tcp-setmss` directive is used and a subsequent rule would allow the traffic to pass.

Jail escape by a privileged user via nullfs

By default, jailed processes cannot mount filesystems, including nullfs(4). However, the allow.mount.nullfs option enables mounting nullfs filesystems, subject to privilege checks. If a privileged user within a jail is able to nullfs-mount directories, a limitation of the kernel's path lookup logic allows that user to escape the jail's chroot, yielding access to the full filesystem of the host or parent jail. In a jail configured to allow nullfs(4) mounts from within the jail, the jailed root user can escape the jail's filesystem root.

Jail chroot escape via fd exchange with a different jail

If two sibling jails are restricted to separate filesystem trees, which is to say that neither of the two jail root directories is an ancestor of the other, jailed processes may nonetheless be able to access a shared directory via a nullfs mount, if the administrator has configured one. In this case, cooperating processes in the two jails may establish a connection using a unix domain socket and exchange directory descriptors with each other. When performing a filesystem name lookup, at each step of the lookup, the kernel checks whether the lookup would descend below the jail root of the current process. If the jail root directory is not encountered, the lookup continues. In a configuration where processes in two different jails are able to exchange file descriptors using a unix domain socket, it is possible for a jailed process to receive a directory for a descriptor that is below that process' jail root. This enables full filesystem access for a jailed process, breaking the chroot. Note that the system administrator is still responsible for ensuring that an unprivileged user on the jail host is not able to pass directory descriptors to a jailed process, even in a patched kernel.

Multiple issues in ctl(4) CAM Target Layer

The ctl_write_buffer and ctl_read_buffer functions allocated memory to be returned to userspace, without initializing it. Malicious software running in a guest VM that exposes virtio_scsi can exploit the vulnerabilities to achieve code execution on the host in the bhyve userspace process, which typically runs as root. Note that bhyve runs in a Capsicum sandbox, so malicious code is constrained by the capabilities available to the bhyve process. A malicious iSCSI initiator could achieve remote code execution on the iSCSI target host.

Multiple issues in ctl(4) CAM Target Layer

The function ctl_write_buffer incorrectly set a flag which resulted in a kernel Use-After-Free when a command finished processing. Malicious software running in a guest VM that exposes virtio_scsi can exploit the vulnerabilities to achieve code execution on the host in the bhyve userspace process, which typically runs as root. Note that bhyve runs in a Capsicum sandbox, so malicious code is constrained by the capabilities available to the bhyve process. A malicious iSCSI initiator could achieve remote code execution on the iSCSI target host.

Multiple issues in ctl(4) CAM Target Layer

The ctl_request_sense function could expose up to three bytes of the kernel heap to userspace. Malicious software running in a guest VM that exposes virtio_scsi can exploit the vulnerabilities to achieve code execution on the host in the bhyve userspace process, which typically runs as root. Note that bhyve runs in a Capsicum sandbox, so malicious code is constrained by the capabilities available to the bhyve process. A malicious iSCSI initiator could achieve remote code execution on the iSCSI target host.

Multiple issues in ctl(4) CAM Target Layer

The ctl_report_supported_opcodes function did not sufficiently validate a field provided by userspace, allowing an arbitrary write to a limited amount of kernel help memory. Malicious software running in a guest VM that exposes virtio_scsi can exploit the vulnerabilities to achieve code execution on the host in the bhyve userspace process, which typically runs as root. Note that bhyve runs in a Capsicum sandbox, so malicious code is constrained by the capabilities available to the bhyve process. A malicious iSCSI initiator could achieve remote code execution on the iSCSI target host.

OpenZFS through 2.1.13 and 2.2.x through 2.2.1, in certain scenarios involving applications that try to rely on efficient copying of file data, can replace file contents with zero-valued bytes and thus potentially disable security mechanisms. NOTE: this issue is not always security related, but can be security related in realistic situations. A possible example is cp, from a recent GNU Core Utilities (coreutils) version, when attempting to preserve a rule set for denying unauthorized access. (One might use cp when configuring access control, such as with the /etc/hosts.deny file specified in the IBM Support reference.) NOTE: this issue occurs less often in version 2.2.1, and in versions before 2.1.4, because of the default configuration in those versions.

Remote denial of service in IPv6 fragment reassembly

A set of carefully crafted ipv6 packets can trigger an integer overflow in the calculation of a fragment reassembled packet's payload length field. This allows an attacker to trigger a kernel panic, resulting in a denial of service.