Race condition in the setsid function in Linux before 2.6.8.1 allows local users to cause a denial of service (crash) and possibly access portions of kernel memory, related to TTY changes, locking, and semaphores.

CAN-2004-0176 :

Michael Kerrisk noticed an insufficient permission checking in the shmctl() function. Any process was permitted to lock/unlock any System V shared memory segment that fell within the the RLIMIT_MEMLOCK limit (that is the maximum size of shared memory that unprivileged users can acquire). This allowed am unprivileged user process to unlock locked memory of other processes, thereby allowing them to be swapped out.
Usually locked shared memory is used to store passphrases and other sensitive content which must not be written to the swap space (where it could be read out even after a reboot).

CAN-2005-0177 :

OGAWA Hirofumi noticed that the table sizes in nls_ascii.c were incorrectly set to 128 instead of 256. This caused a buffer overflow in some cases which could be exploited to crash the kernel.

CAN-2005-0178 :

A race condition was found in the terminal handling of the 'setsid()' function, which is used to start new process sessions.

http://oss.sgi.com/archives/netdev/2005-01/msg01036.html :

David Coulson noticed a design flaw in the netfilter/iptables module.
By sending specially crafted packets, a remote attacker could exploit this to crash the kernel or to bypass firewall rules.

Fixing this vulnerability required a change in the Application Binary Interface (ABI) of the kernel. This means that third-party user installed modules might not work any more with the new kernel, so this fixed kernel has a new ABI version number. You have to recompile and reinstall all third-party modules.

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Multiple vulnerabilities in the Linux kernel have been discovered and fixed in this update. The following CVE names have been fixed in the LE2005 kernel :

Colin Percival discovered a vulnerability in Intel's Hyper-Threading technology could allow a local user to use a malicious thread to create covert channels, monitor the execution of other threads, and obtain sensitive information such as cryptographic keys via a timing attack on memory cache misses. This has been corrected by disabling HT support in all kernels (CVE-2005-0109).

An information leak in the ext2 filesystem code in kernels prior to 2.6.11.6 was found where when a new directory is created, the ext2 block written to disk is not initialized (CVE-2005-0400).

A flaw when freeing a pointer in load_elf_library was found in kernels prior to 2.6.11.6 that could be abused by a local user to potentially crash the machine causing a Denial of Service (CVE-2005-0749).

A problem with the Bluetooth kernel stack in kernels 2.4.6 through 2.4.30-rc1 and 2.6 through 2.6.11.5 could be used by a local attacker to gain root access or crash the machine (CVE-2005-0750).

Paul Starzetz found an integer overflow in the ELF binary format loader's code dump function in kernels prior to and including 2.4.31-pre1 and 2.6.12-rc4. By creating and executing a specially crafted ELF executable, a local attacker could exploit this to execute arbitrary code with root and kernel privileges (CVE-2005-1263).

The drivers for raw devices used the wrong function to pass arguments to the underlying block device in 2.6.x kernels. This made the kernel address space accessible to user-space applications allowing any local user with at least read access to a device in /dev/raw/* (usually only root) to execute arbitrary code with kernel privileges (CVE-2005-1264).

The it87 and via686a hardware monitor drivers in kernels prior to 2.6.11.8 and 2.6.12 prior to 2.6.12-rc2 created a sysfs file named 'alarms' with write permissions although they are not designed to be writable. This allowed a local user to crash the kernel by attempting to write to these files (CVE-2005-1369).

In addition to the above-noted CVE-2005-0109, CVE-2005-0400, CVE-2005-0749, CVE-2005-0750, and CVE-2005-1369 fixes, the following CVE names have been fixed in the 10.1 kernel :

The POSIX Capability Linux Security Module (LSM) for 2.6 kernels up to and including 2.6.8.1 did not properly handle the credentials of a process that is launched before the module is loaded, which could be used by local attackers to gain elevated privileges (CVE-2004-1337).

A flaw in the Linux PPP driver in kernel 2.6.8.1 was found where on systems allowing remote users to connect to a server via PPP, a remote client could cause a crash, resulting in a Denial of Service (CVE-2005-0384).

George Guninski discovered a buffer overflow in the ATM driver in kernels 2.6.10 and 2.6.11 before 2.6.11-rc4 where the atm_get_addr() function does not validate its arguments sufficiently which could allow a local attacker to overwrite large portions of kernel memory by supplying a negative length argument. This could potentially lead to the execution of arbitrary code (CVE-2005-0531).

The reiserfs_copy_from_user_to_file_region function in reiserfs/file.c before kernel 2.6.11, when running on 64-bit architectures, could allow local users to trigger a buffer overflow as a result of casting discrepancies between size_t and int data types. This could allow an attacker to overwrite kernel memory, crash the machine, or potentially obtain root access (CVE-2005-0532).

A race condition in the Radeon DRI driver in kernel 2.6.8.1 allows a local user with DRI privileges to execute arbitrary code as root (CVE-2005-0767).

Access was not restricted to the N_MOUSE discipline for a TTY in kernels prior to 2.6.11. This could allow local attackers to obtain elevated privileges by injecting mouse or keyboard events into other user's sessions (CVE-2005-0839).

Some futex functions in futex.c in 2.6 kernels performed get_user calls while holding the mmap_sem semaphore, which could allow a local attacker to cause a deadlock condition in do_page_fault by triggering get_user faults while another thread is executing mmap or other functions (CVE-2005-0937).

In addition to the above-noted CVE-2004-1337, CVE-2005-0109, CVE-2005-0384, CVE-2005-0400, CVE-2005-0531, CVE-2005-0532, CVE-2005-0749, CVE-2005-0750, CVE-2005-0767, CVE-2005-0839, CVE-2005-0937, CVE-2005-1263, CVE-2005-1264, and CVE-2005-1369 fixes, the following CVE names have been fixed in the 10.0/ Corporate 3.0 kernels :

A race condition in the setsid function in kernels before 2.6.8.1 could allow a local attacker to cause a Denial of Service and possibly access portions of kernel memory related to TTY changes, locking, and semaphores (CVE-2005-0178).

When forwarding fragmented packets in kernel 2.6.8.1, a hardware assisted checksum could only be used once which could lead to a Denial of Service attack or crash by remote users (CVE-2005-0209).

A signedness error in the copy_from_read_buf function in n_tty.c before kernel 2.6.11 allows local users to read kernel memory via a negative argument (CVE-2005-0530).

A vulnerability in the fib_seq_start() function allowed a local user to crash the system by readiung /proc/net/route in a certain way, causing a Denial of Service (CVE-2005-1041).

A vulnerability in the Direct Rendering Manager (DRM) driver in the 2.6 kernel does not properly check the DMA lock, which could allow remote attackers or local users to cause a Denial of Service (X Server crash) and possibly modify the video output (CVE-2004-1056).

The remote Redhat Enterprise Linux 4 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2005:092 advisory.

    The Linux kernel handles the basic functions of the operating system.

    This advisory includes fixes for several security issues:

    iSEC Security Research discovered multiple vulnerabilities in the IGMP     functionality.  These flaws could allow a local user to cause a denial of     service (crash) or potentially gain privileges.  Where multicast     applications are being used on a system, these flaws may also allow remote     users to cause a denial of service.  The Common Vulnerabilities and     Exposures project (cve.mitre.org) has assigned the name CAN-2004-1137 to     this issue.

    iSEC Security Research discovered a flaw in the page fault handler code     that could lead to local users gaining elevated (root) privileges on     multiprocessor machines.  (CAN-2005-0001)

    iSEC Security Research discovered a VMA handling flaw in the uselib(2)     system call of the Linux kernel.  A local user could make use of this     flaw to gain elevated (root) privileges.  (CAN-2004-1235)

    A flaw affecting the OUTS instruction on the AMD64 and Intel EM64T     architecture was discovered.  A local user could use this flaw to write to     privileged IO ports.  (CAN-2005-0204)

    The Direct Rendering Manager (DRM) driver in Linux kernel 2.6 does not     properly check the DMA lock, which could allow remote attackers or local     users to cause a denial of service (X Server crash) or possibly modify the     video output. (CAN-2004-1056)

    OGAWA Hirofumi discovered incorrect tables sizes being used in the     filesystem Native Language Support ASCII translation table.  This could     lead to a denial of service (system crash).  (CAN-2005-0177)

    Michael Kerrisk discovered a flaw in the 2.6.9 kernel which allows users to     unlock arbitrary shared memory segments.  This flaw could lead to     applications not behaving as expected.  (CAN-2005-0176)

    Improvements in the POSIX signal and tty standards compliance exposed     a race condition.  This flaw can be triggered accidentally by threaded     applications or deliberately by a malicious user and can result in a     denial of service (crash) or in occasional cases give access to a small     random chunk of kernel memory.  (CAN-2005-0178)

    The PaX team discovered a flaw in mlockall introduced in the 2.6.9 kernel.
    An unprivileged user could use this flaw to cause a denial of service     (CPU and memory consumption or crash).  (CAN-2005-0179)

    Brad Spengler discovered multiple flaws in sg_scsi_ioctl in the 2.6 kernel.
    An unprivileged user may be able to use this flaw to cause a denial of     service (crash) or possibly other actions.  (CAN-2005-0180)

    Kirill Korotaev discovered a missing access check regression in the Red Hat     Enterprise Linux 4 kernel 4GB/4GB split patch.  On systems using the     hugemem kernel, a local unprivileged user could use this flaw to cause a     denial of service (crash).  (CAN-2005-0090)

    A flaw in the Red Hat Enterprise Linux 4 kernel 4GB/4GB split patch can     allow syscalls to read and write arbitrary kernel memory.  On systems using     the hugemem kernel, a local unprivileged user could use this flaw to gain     privileges.  (CAN-2005-0091)

    An additional flaw in the Red Hat Enterprise Linux 4 kernel 4GB/4GB split     patch was discovered. On x86 systems using the hugemem kernel, a local     unprivileged user may be able to use this flaw to cause a denial of service     (crash).  (CAN-2005-0092)

    All Red Hat Enterprise Linux 4 users are advised to upgrade their     kernels to the packages associated with their machine architectures     and configurations as listed in this erratum.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
20706	Ubuntu 4.10 : linux-source-2.6.8.1 vulnerabilities (USN-82-1)	Nessus	Ubuntu Local Security Checks	high
18598	Mandrake Linux Security Advisory : kernel (MDKSA-2005:110)	Nessus	Mandriva Local Security Checks	high
17183	RHEL 4 : kernel (RHSA-2005:092)	Nessus	Red Hat Local Security Checks	high

Detections

Analytics

CVE-2005-0178

medium

Tenable Plugins

high

high

high