CVE-2023-53320

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

scsi: mpi3mr: Fix issues in mpi3mr_get_all_tgt_info()

The function mpi3mr_get_all_tgt_info() has four issues:

1. It calculates valid entry length in alltgt_info assuming the header part of the struct mpi3mr_device_map_info would equal to sizeof(u32). The correct size is sizeof(u64).

2. When it calculates the valid entry length kern_entrylen, it excludes one entry by subtracting 1 from num_devices.

3. It copies num_device by calling memcpy(). Substitution is enough.

4. It does not specify the calculated length to sg_copy_from_buffer(). Instead, it specifies the payload length which is larger than the alltgt_info size. It causes BUG: KASAN: slab-out-of-bounds.

Fix the issues by using the correct header size, removing the subtraction from num_devices, replacing the memcpy() with substitution and specifying the correct length to sg_copy_from_buffer().

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/2f3d3fa5b8ed7d3b147478f42b00b468eeb1ecd2
• https://git.kernel.org/stable/c/8ba997b22f2cd5d29aad8c39f6201f7608ed0c04
• https://git.kernel.org/stable/c/fb428a2005fc1260d18b989cc5199f281617f44d