CVE-2023-4194

A flaw was found in the Linux kernels TUN/TAP functionality. This issue could allow a local user to bypass network filters and gain unauthorized access to some resources. The original patches fixing CVE-2023-1076 are incorrect or incomplete. The problem is that the following upstream commits - a096ccca6e50 (tun: tun_chr_open(): correctly initialize socket uid), - 66b2c338adce (tap: tap_open(): correctly initialize socket uid), pass inode->i_uid to sock_init_data_uid() as the last parameter and that turns out to not be accurate.

Weakness

The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.

Affected Software

Extended Description

When the product accesses the resource using an incompatible type, this could trigger logical errors because the resource does not have expected properties. In languages without memory safety, such as C and C++, type confusion can lead to out-of-bounds memory access. While this weakness is frequently associated with unions when parsing data with many different embedded object types in C, it can be present in any application that can interpret the same variable or memory location in multiple ways. This weakness is not unique to C and C++. For example, errors in PHP applications can be triggered by providing array parameters when scalars are expected, or vice versa. Languages such as Perl, which perform automatic conversion of a variable of one type when it is accessed as if it were another type, can also contain these issues.

References

• https://access.redhat.com/errata/RHSA-2023:6583
• https://access.redhat.com/security/cve/CVE-2023-4194
• https://bugzilla.redhat.com/show_bug.cgi?id=2229498
• https://lore.kernel.org/all/20230731164237.48365-1-lersek@redhat.com/
• https://lore.kernel.org/all/20230731164237.48365-2-lersek@redhat.com/
• https://lore.kernel.org/all/20230731164237.48365-3-lersek@redhat.com/
• https://access.redhat.com/errata/RHSA-2023:6583
• https://access.redhat.com/security/cve/CVE-2023-4194
• https://bugzilla.redhat.com/show_bug.cgi?id=2229498
• https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/344H6HO6SSC4KT7PDFXSDIXKMKHISSGF/
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3TYLSJ2SAI7RF56ZLQ5CQWCJLVJSD73Q/
• https://lore.kernel.org/all/20230731164237.48365-1-lersek@redhat.com/
• https://lore.kernel.org/all/20230731164237.48365-2-lersek@redhat.com/
• https://lore.kernel.org/all/20230731164237.48365-3-lersek@redhat.com/
• https://security.netapp.com/advisory/ntap-20231027-0002/
• https://www.debian.org/security/2023/dsa-5480
• https://www.debian.org/security/2023/dsa-5492