CVE-2023-53214

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

f2fs: fix to avoid potential memory corruption in __update_iostat_latency()

Add iotype sanity check to avoid potential memory corruption. This is to fix the compile error below:

fs/f2fs/iostat.c:231 __update_iostat_latency() error: buffer overflow io_lat->peak_lat[type] 3 <= 3

vim +228 fs/f2fs/iostat.c

211 static inline void __update_iostat_latency(struct bio_iostat_ctx *iostat_ctx, 212 enum iostat_lat_type type) 213 { 214 unsigned long ts_diff; 215 unsigned int page_type = iostat_ctx->type; 216 struct f2fs_sb_info *sbi = iostat_ctx->sbi; 217 struct iostat_lat_info *io_lat = sbi->iostat_io_lat; 218 unsigned long flags; 219 220 if (!sbi->iostat_enable) 221 return; 222 223 ts_diff = jiffies - iostat_ctx->submit_ts; 224 if (page_type >= META_FLUSH) ^^^^^^^^^^

225 page_type = META; 226 227 spin_lock_irqsave(&sbi->iostat_lat_lock, flags); @228 io_lat->sum_lat[type][page_type] += ts_diff; ^^^^^^^^^ Mixup between META_FLUSH and NR_PAGE_TYPE leads to memory corruption.

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/0dbbf0fb38d5ec5d4138d1aeaeb43d9217b9a592
• https://git.kernel.org/stable/c/20b4f3de0f3932f71b4a8daf0671e517a8d98022
• https://git.kernel.org/stable/c/22ddbbff116ee7dce5431feb1c0f36a507d2d68d
• https://git.kernel.org/stable/c/aa4d726af72a21732ce120484e0b1240674a13b3