Azure RTOS FileX is a FAT-compatible file system that’s fully integrated with Azure RTOS ThreadX. In versions before 6.2.0, the Fault Tolerant feature of Azure RTOS FileX includes integer under and overflows which may be exploited to achieve buffer overflow and modify memory contents. When a valid log file with correct ID and checksum is detected by the `_fx_fault_tolerant_enable` function an attempt to recover the previous failed write operation is taken by call of `_fx_fault_tolerant_apply_logs`. This function iterates through the log entries and performs required recovery operations. When properly crafted a log including entries of type `FX_FAULT_TOLERANT_DIR_LOG_TYPE` may be utilized to introduce unexpected behavior. This issue has been patched in version 6.2.0. A workaround to fix line 218 in fx_fault_tolerant_apply_logs.c is documented in the GHSA.
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow.
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
| Link | Tags |
|---|---|
| https://github.com/azure-rtos/filex/security/advisories/GHSA-8jqf-wjhq-4w9f | mitigation third party advisory exploit |
| https://github.com/azure-rtos/filex/blob/master/common/src/fx_fault_tolerant_apply_logs.c#L218 | third party advisory patch |