Several local and remote vulnerabilities have been discovered in the Linux kernel that may lead to a denial of service or the execution of arbitrary code. The Common Vulnerabilities and Exposures project identifies the following problems: CVE-2005-3359 Franz Filz discovered that some socket calls permit causing inconsistent reference counts on loadable modules, which allows local users to cause a denial of service. CVE-2006-0038 "Solar Designer" discovered that arithmetic computations in netfilter's do_replace() function can lead to a buffer overflow and the execution of arbitrary code. However, the operation requires CAP_NET_ADMIN privileges, which is only an issue in virtualization systems or fine grained access control systems. CVE-2006-0039 "Solar Designer" discovered a race condition in netfilter's do_add_counters() function, which allows information disclosure of kernel memory by exploiting a race condition. Likewise, it requires CAP_NET_ADMIN privileges. CVE-2006-0456 David Howells discovered that the s390 assembly version of the strnlen_user() function incorrectly returns some string size values. CVE-2006-0554 It was discovered that the ftruncate() function of XFS can expose unallocated blocks, which allows information disclosure of previously deleted files. CVE-2006-0555 It was discovered that some NFS file operations on handles mounted with O_DIRECT can force the kernel into a crash. CVE-2006-0557 It was discovered that the code to configure memory policies allows tricking the kernel into a crash, thus allowing denial of service. CVE-2006-0558 It was discovered by Cliff Wickman that perfmon for the IA64 architecture allows users to trigger a BUG() assert, which allows denial of service. CVE-2006-0741 Intel EM64T systems were discovered to be susceptible to a local DoS due to an endless recursive fault related to a bad ELF entry address. CVE-2006-0742 Alan and Gareth discovered that the ia64 platform had an incorrectly declared die_if_kernel() function as "does never return" which could be exploited by a local attacker resulting in a kernel crash. CVE-2006-0744 The Linux kernel did not properly handle uncanonical return addresses on Intel EM64T CPUs, reporting exceptions in the SYSRET instead of the next instruction, causing the kernel exception handler to run on the user stack with the wrong GS. This may result in a DoS due to a local user changing the frames. CVE-2006-1056 AMD64 machines (and other 7th and 8th generation AuthenticAMD processors) were found to be vulnerable to sensitive information leakage, due to how they handle saving and restoring the FOP, FIP, and FDP x87 registers in FXSAVE/FXRSTOR when an exception is pending. This allows a process to determine portions of the state of floating point instructions of other processes. CVE-2006-1242 Marco Ivaldi discovered that there was an unintended information disclosure allowing remote attackers to bypass protections against Idle Scans (nmap -sI) by abusing the ID field of IP packets and bypassing the zero IP ID in DF packet countermeasure. This was a result of the ip_push_pending_frames function improperly incremented the IP ID field when sending a RST after receiving unsolicited TCP SYN-ACK packets. CVE-2006-1368 Shaun Tancheff discovered a buffer overflow (boundary condition error) in the USB Gadget RNDIS implementation allowing remote attackers to cause a DoS. While creating a reply message, the driver allocated memory for the reply data, but not for the reply structure. The kernel fails to properly bounds-check user-supplied data before copying it to an insufficiently sized memory buffer. Attackers could crash the system, or possibly execute arbitrary machine code. CVE-2006-1523 Oleg Nesterov reported an unsafe BUG_ON call in signal.c which was introduced by RCU signal handling. The BUG_ON code is protected by siglock while the code in switch_exit_pids() uses tasklist_lock. It may be possible for local users to exploit this to initiate a denial of service attack (DoS). CVE-2006-1524 Hugh Dickins discovered an issue in the madvise_remove() function wherein file and mmap restrictions are not followed, allowing local users to bypass IPC permissions and replace portions of readonly tmpfs files with zeroes. CVE-2006-1525 Alexandra Kossovsky reported a NULL pointer dereference condition in ip_route_input() that can be triggered by a local user by requesting a route for a multicast IP address, resulting in a denial of service (panic). CVE-2006-1857 Vlad Yasevich reported a data validation issue in the SCTP subsystem that may allow a remote user to overflow a buffer using a badly formatted HB-ACK chunk, resulting in a denial of service. CVE-2006-1858 Vlad Yasevich reported a bug in the bounds checking code in the SCTP subsystem that may allow a remote attacker to trigger a denial of service attack when rounded parameter lengths are used to calculate parameter lengths instead of the actual values. CVE-2006-1863 Mark Mosely discovered that chroots residing on an CIFS share can be escaped with specially crafted "cd" sequences. CVE-2006-1864 Mark Mosely discovered that chroots residing on an SMB share can be escaped with specially crafted "cd" sequences. CVE-2006-2271 The "Mu security team" discovered that carefully crafted ECNE chunks can cause a kernel crash by accessing incorrect state stable entries in the SCTP networking subsystem, which allows denial of service. CVE-2006-2272 The "Mu security team" discovered that fragmented SCTP control chunks can trigger kernel panics, which allows for denial of service attacks. CVE-2006-2274 It was discovered that SCTP packets with two initial bundled data packets can lead to infinite recursion, which allows for denial of service attacks. The following matrix explains which kernel version for which architecture fix the problems mentioned above: Debian 3.1 (sarge) Source 2.6.8-16sarge3 Alpha architecture 2.6.8-16sarge3 HP Precision architecture 2.6.8-6sarge3 Intel IA-32 architecture 2.6.8-16sarge3 Intel IA-64 architecture 2.6.8-14sarge3 Motorola 680x0 architecture 2.6.8-4sarge3 PowerPC architecture 2.6.8-12sarge3 IBM S/390 architecture 2.6.8-5sarge3 Sun Sparc architecture 2.6.8-15sarge3 Due to technical problems the built amd64 packages couldn't be processed by the archive script. Once this problem is resolved, an updated DSA 1103-2 will be sent out with the checksums for amd64. The following matrix lists additional packages that were rebuilt for compatibility with or to take advantage of this update: Debian 3.1 (sarge) fai-kernels 1.9.1sarge2 We recommend that you upgrade your kernel package immediately and reboot the machine. If you have built a custom kernel from the kernel source package, you will need to rebuild to take advantage of these fixes.
Several local and remote vulnerabilities have been discovered in the Linux kernel that may lead to a denial of service or the execution of arbitrary code. The Common Vulnerabilities and Exposures project identifies the following problems:
Franz Filz discovered that some socket calls permit causing inconsistent reference counts on loadable modules, which allows local users to cause a denial of service.
"Solar Designer" discovered that arithmetic computations in netfilter's do_replace() function can lead to a buffer overflow and the execution of arbitrary code. However, the operation requires CAP_NET_ADMIN privileges, which is only an issue in virtualization systems or fine grained access control systems.
"Solar Designer" discovered a race condition in netfilter's do_add_counters() function, which allows information disclosure of kernel memory by exploiting a race condition. Likewise, it requires CAP_NET_ADMIN privileges.
David Howells discovered that the s390 assembly version of the strnlen_user() function incorrectly returns some string size values.
It was discovered that the ftruncate() function of XFS can expose unallocated blocks, which allows information disclosure of previously deleted files.
It was discovered that some NFS file operations on handles mounted with O_DIRECT can force the kernel into a crash.
It was discovered that the code to configure memory policies allows tricking the kernel into a crash, thus allowing denial of service.
It was discovered by Cliff Wickman that perfmon for the IA64 architecture allows users to trigger a BUG() assert, which allows denial of service.
Intel EM64T systems were discovered to be susceptible to a local DoS due to an endless recursive fault related to a bad ELF entry address.
Alan and Gareth discovered that the ia64 platform had an incorrectly declared die_if_kernel() function as "does never return" which could be exploited by a local attacker resulting in a kernel crash.
The Linux kernel did not properly handle uncanonical return addresses on Intel EM64T CPUs, reporting exceptions in the SYSRET instead of the next instruction, causing the kernel exception handler to run on the user stack with the wrong GS. This may result in a DoS due to a local user changing the frames.
AMD64 machines (and other 7th and 8th generation AuthenticAMD processors) were found to be vulnerable to sensitive information leakage, due to how they handle saving and restoring the FOP, FIP, and FDP x87 registers in FXSAVE/FXRSTOR when an exception is pending. This allows a process to determine portions of the state of floating point instructions of other processes.
Marco Ivaldi discovered that there was an unintended information disclosure allowing remote attackers to bypass protections against Idle Scans (nmap -sI) by abusing the ID field of IP packets and bypassing the zero IP ID in DF packet countermeasure. This was a result of the ip_push_pending_frames function improperly incremented the IP ID field when sending a RST after receiving unsolicited TCP SYN-ACK packets.
Shaun Tancheff discovered a buffer overflow (boundary condition error) in the USB Gadget RNDIS implementation allowing remote attackers to cause a DoS. While creating a reply message, the driver allocated memory for the reply data, but not for the reply structure. The kernel fails to properly bounds-check user-supplied data before copying it to an insufficiently sized memory buffer. Attackers could crash the system, or possibly execute arbitrary machine code.
Oleg Nesterov reported an unsafe BUG_ON call in signal.c which was introduced by RCU signal handling. The BUG_ON code is protected by siglock while the code in switch_exit_pids() uses tasklist_lock. It may be possible for local users to exploit this to initiate a denial of service attack (DoS).
Hugh Dickins discovered an issue in the madvise_remove() function wherein file and mmap restrictions are not followed, allowing local users to bypass IPC permissions and replace portions of readonly tmpfs files with zeroes.
Alexandra Kossovsky reported a NULL pointer dereference condition in ip_route_input() that can be triggered by a local user by requesting a route for a multicast IP address, resulting in a denial of service (panic).
Vlad Yasevich reported a data validation issue in the SCTP subsystem that may allow a remote user to overflow a buffer using a badly formatted HB-ACK chunk, resulting in a denial of service.
Vlad Yasevich reported a bug in the bounds checking code in the SCTP subsystem that may allow a remote attacker to trigger a denial of service attack when rounded parameter lengths are used to calculate parameter lengths instead of the actual values.
Mark Mosely discovered that chroots residing on an CIFS share can be escaped with specially crafted "cd" sequences.
Mark Mosely discovered that chroots residing on an SMB share can be escaped with specially crafted "cd" sequences.
The "Mu security team" discovered that carefully crafted ECNE chunks can cause a kernel crash by accessing incorrect state stable entries in the SCTP networking subsystem, which allows denial of service.
The "Mu security team" discovered that fragmented SCTP control chunks can trigger kernel panics, which allows for denial of service attacks.
It was discovered that SCTP packets with two initial bundled data packets can lead to infinite recursion, which allows for denial of service attacks.
The following matrix explains which kernel version for which architecture fix the problems mentioned above:
| Debian 3.1 (sarge) | |
|---|---|
| Source | 2.6.8-16sarge3 |
| Alpha architecture | 2.6.8-16sarge3 |
| HP Precision architecture | 2.6.8-6sarge3 |
| Intel IA-32 architecture | 2.6.8-16sarge3 |
| Intel IA-64 architecture | 2.6.8-14sarge3 |
| Motorola 680x0 architecture | 2.6.8-4sarge3 |
| PowerPC architecture | 2.6.8-12sarge3 |
| IBM S/390 architecture | 2.6.8-5sarge3 |
| Sun Sparc architecture | 2.6.8-15sarge3 |
Due to technical problems the built amd64 packages couldn't be processed by the archive script. Once this problem is resolved, an updated DSA 1103-2 will be sent out with the checksums for amd64.
The following matrix lists additional packages that were rebuilt for compatibility with or to take advantage of this update:
| Debian 3.1 (sarge) | |
|---|---|
| fai-kernels | 1.9.1sarge2 |
We recommend that you upgrade your kernel package immediately and reboot the machine. If you have built a custom kernel from the kernel source package, you will need to rebuild to take advantage of these fixes.
MD5 checksums of the listed files are available in the original advisory.
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