CVE-2021-26932 - log back

CVE-2021-26932 edited at 23 Feb 2021 19:54:32
Description
- An issue was discovered in the Linux kernel 3.2 through 5.10.16, as used by Xen. Grant mapping operations often occur in batch hypercalls, where a number of operations are done in a single hypercall, the success or failure of each one is reported to the backend driver, and the backend driver then loops over the results, performing follow-up actions based on the success or failure of each operation. Unfortunately, when running in PV mode, the Linux backend drivers mishandle this: Some errors are ignored, effectively implying their success from the success of related batch elements. In other cases, errors resulting from one batch element lead to further batch elements not being inspected, and hence successful ones to not be possible to properly unmap upon error recovery. Only systems with Linux backends running in PV mode are vulnerable. Linux backends run in HVM / PVH modes are not vulnerable. This affects arch/*/xen/p2m.c and drivers/xen/gntdev.c.
+ An issue was discovered in the Linux kernel 3.2 up to 5.10.17, as used by Xen. Grant mapping operations often occur in batch hypercalls, where a number of operations are done in a single hypercall, the success or failure of each one is reported to the backend driver, and the backend driver then loops over the results, performing follow-up actions based on the success or failure of each operation. Unfortunately, when running in PV mode, the Linux backend drivers mishandle this: Some errors are ignored, effectively implying their success from the success of related batch elements. In other cases, errors resulting from one batch element lead to further batch elements not being inspected, and hence successful ones to not be possible to properly unmap upon error recovery. Only systems with Linux backends running in PV mode are vulnerable. Linux backends run in HVM / PVH modes are not vulnerable. This affects arch/*/xen/p2m.c and drivers/xen/gntdev.c.
CVE-2021-26932 edited at 23 Feb 2021 19:51:09
References
https://xenbits.xen.org/xsa/advisory-361.html
+ https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.11.1&id=76b0be126b8a7448892d851a3c0a304d91c9ee58
+ https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.11.1&id=86c464450c578fcb8c18dee6597b6453ae6aa21e
+ https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.11.1&id=ca0ca64ce9e9bcc6922eab8b85a599451e85730d
+ https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.11.1&id=5b36827850b367454e72958c501bc3c2012239bb
+ https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.11.1&id=b02356a0f7e41a16d6e43c419c7cf7adb0b1403a
+ https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.10.18&id=740f4d9d0c34ea99279acf2fc99ae33c0142265a
+ https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.10.18&id=0c08037b56a77219a6ec67c2cb19abf38722a525
+ https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.10.18&id=1a5c2274349f5b6f3b6bbdf43247e71a50ae6e2f
+ https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.10.18&id=be89a0300a58c273b6f48bb8db01c807e203098b
+ https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.10.18&id=0462dbbe2cab43528f943575b510625cf422921a
CVE-2021-26932 edited at 17 Feb 2021 14:08:13
Description
+ An issue was discovered in the Linux kernel 3.2 through 5.10.16, as used by Xen. Grant mapping operations often occur in batch hypercalls, where a number of operations are done in a single hypercall, the success or failure of each one is reported to the backend driver, and the backend driver then loops over the results, performing follow-up actions based on the success or failure of each operation. Unfortunately, when running in PV mode, the Linux backend drivers mishandle this: Some errors are ignored, effectively implying their success from the success of related batch elements. In other cases, errors resulting from one batch element lead to further batch elements not being inspected, and hence successful ones to not be possible to properly unmap upon error recovery. Only systems with Linux backends running in PV mode are vulnerable. Linux backends run in HVM / PVH modes are not vulnerable. This affects arch/*/xen/p2m.c and drivers/xen/gntdev.c.
- A security issue was found in the Xen module of the Linux kernel. Grant mapping operations often occur in batch hypercalls, where a number of operations are done in a single hypercall, the success or failure of each one reported to the backend driver, and the backend driver then loops over the results, performing follow-up actions based on the success or failure of each operation.
-
- Unfortunately, when running in PV mode, the Linux backend drivers mishandle this: Some errors are ignored, effectively implying their success from the success of related batch elements. In other cases, errors resulting from one batch element lead to further batch elements not being inspected, and hence successful ones to not be possible to properly unmap upon error recovery.
-
- A malicious or buggy frontend driver may be able to crash the corresponding backend driver, causing a denial of service potentially affecting the entire domain running the backend driver. A malicious or buggy frontend driver may be able to cause resource leaks in the domain running the corresponding backend driver, leading to a denial of service.
CVE-2021-26932 edited at 16 Feb 2021 15:57:06
References
- https://www.openwall.com/lists/oss-security/2021/02/16/3
+ https://xenbits.xen.org/xsa/advisory-361.html
CVE-2021-26932 edited at 16 Feb 2021 15:55:21
Severity
- Unknown
+ Low
Remote
- Unknown
+ Local
Type
- Unknown
+ Denial of service
Description
+ A security issue was found in the Xen module of the Linux kernel. Grant mapping operations often occur in batch hypercalls, where a number of operations are done in a single hypercall, the success or failure of each one reported to the backend driver, and the backend driver then loops over the results, performing follow-up actions based on the success or failure of each operation.
+
+ Unfortunately, when running in PV mode, the Linux backend drivers mishandle this: Some errors are ignored, effectively implying their success from the success of related batch elements. In other cases, errors resulting from one batch element lead to further batch elements not being inspected, and hence successful ones to not be possible to properly unmap upon error recovery.
+
+ A malicious or buggy frontend driver may be able to crash the corresponding backend driver, causing a denial of service potentially affecting the entire domain running the backend driver. A malicious or buggy frontend driver may be able to cause resource leaks in the domain running the corresponding backend driver, leading to a denial of service.
References
+ https://www.openwall.com/lists/oss-security/2021/02/16/3
Notes
CVE-2021-26932 created at 16 Feb 2021 15:43:36