CVE-2020-11833

Step 1: Trigger Condition: An attacker must be able to interact with the mp2650_data_log_write function, likely through a crafted input to the charger IC driver. Step 2: Parameter Manipulation: The attacker crafts a malicious input, specifically manipulating the len parameter to a value larger than the allocated buffer size within the mp2650_data_log_write function. Step 3: Buffer Overflow: The mp2650_data_log_write function attempts to write data to the buffer, but due to the unchecked len parameter, it overflows the buffer, overwriting adjacent memory. Step 4: Code Execution (Exploitation): The attacker leverages the buffer overflow to overwrite critical data structures, such as the return address or function pointers, to redirect program execution to attacker-controlled code (e.g., shellcode) or to modify kernel data structures to gain elevated privileges. This could lead to a complete system compromise.

The vulnerability lies within the mp2650_data_log_write function in oppo_mp2650.c. The function fails to validate the len parameter, which specifies the size of the data being written. This lack of bounds checking allows an attacker to provide a len value larger than the allocated buffer, leading to a buffer overflow. This overflow can overwrite adjacent memory regions, potentially including critical data structures or even the instruction pointer, enabling arbitrary code execution under the context of the kernel. The root cause is a missing if statement or similar check to ensure len does not exceed the buffer's capacity. This is a classic example of a write-what-where primitive.