CVE-2024-40901

In the Linux kernel, the following vulnerability has been resolved:

scsi: mpt3sas: Avoid test/set_bit() operating in non-allocated memory

There is a potential out-of-bounds access when using test_bit() on a single word. The test_bit() and set_bit() functions operate on long values, and when testing or setting a single word, they can exceed the word boundary. KASAN detects this issue and produces a dump:

 BUG: KASAN: slab-out-of-bounds in _scsih_add_device.constprop.0 (./arch/x86/include/asm/bitops.h:60 ./include/asm-generic/bitops/instrumented-atomic.h:29 drivers/scsi/mpt3sas/mpt3sas_scsih.c:7331) mpt3sas

 Write of size 8 at addr ffff8881d26e3c60 by task kworker/u1536:2/2965

For full log, please look at [1].

Make the allocation at least the size of sizeof(unsigned long) so that set_bit() and test_bit() have sufficient room for read/write operations without overwriting unallocated memory.

[1] Link: https://lore.kernel.org/all/ZkNcALr3W3KGYYJG@gmail.com/

Weakness

The product writes data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

• For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer.

• Be wary that a language’s interface to native code may still be subject to overflows, even if the language itself is theoretically safe.

• Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

• Examples include the Safe C String Library (SafeStr) by Messier and Viega [REF-57], and the Strsafe.h library from Microsoft [REF-56]. These libraries provide safer versions of overflow-prone string-handling functions.

• Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking.

• D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.

• Consider adhering to the following rules when allocating and managing an application’s memory:

• Run or compile the software using features or extensions that randomly arrange the positions of a program’s executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.

• Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as “rebasing” (for Windows) and “prelinking” (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.

• For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

• Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX [REF-60] [REF-61]. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment.

• For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].

References

• https://git.kernel.org/stable/c/0081d2b3ae0a17a86b8cc0fa3c8bdc54e233ba16
• https://git.kernel.org/stable/c/18abb5db0aa9b2d48f7037a88b41af2eef821674
• https://git.kernel.org/stable/c/19649e49a6df07cd2e03e0a11396fd3a99485ec2
• https://git.kernel.org/stable/c/4254dfeda82f20844299dca6c38cbffcfd499f41
• https://git.kernel.org/stable/c/46bab2bcd771e725ff5ca3a68ba68cfeac45676c
• https://git.kernel.org/stable/c/521f333e644c4246ca04a4fc4772edc53dd2a801
• https://git.kernel.org/stable/c/9079338c5a0d1f1fee34fb1c9e99b754efe414c5
• https://git.kernel.org/stable/c/e9bce7c751f6d6c7be88c0bc081a66aaf61a23ee
• https://git.kernel.org/stable/c/0081d2b3ae0a17a86b8cc0fa3c8bdc54e233ba16
• https://git.kernel.org/stable/c/18abb5db0aa9b2d48f7037a88b41af2eef821674
• https://git.kernel.org/stable/c/19649e49a6df07cd2e03e0a11396fd3a99485ec2
• https://git.kernel.org/stable/c/4254dfeda82f20844299dca6c38cbffcfd499f41
• https://git.kernel.org/stable/c/46bab2bcd771e725ff5ca3a68ba68cfeac45676c
• https://git.kernel.org/stable/c/521f333e644c4246ca04a4fc4772edc53dd2a801
• https://git.kernel.org/stable/c/9079338c5a0d1f1fee34fb1c9e99b754efe414c5
• https://git.kernel.org/stable/c/e9bce7c751f6d6c7be88c0bc081a66aaf61a23ee
• https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html