CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's framebuffer device (fbdev), specifically in the fb_io_read() function, where a desynchronization of pointers can lead to out-of-bounds I/O reads if a partial copy occurs due to a faulty user buffer. This flaw could allow an attacker to exploit the system by causing excessive hardware reads, potentially leading to information leakage or system instability. Organizations using affected Linux kernel versions should prioritize patching this vulnerability to safeguard against potential exploitation.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: fbdev: core: Fix pointer desynchronization in fb_io_read() In fb_io_read(), if copy_to_user() performs a partial copy (e.g., due to a faulty user buffer), the loop adjusts the chunk size 'c' and updates the remaining 'count'. However, the hardware 'src' pointer has already been eagerly advanced by the original chunk size. If the loop is allowed to continue, the read will resume from an incorrect, over-advanced offset. Since the remaining 'count' was only decremented by the successful bytes, this desynchronization causes the next iterations to execute more hardware reads than originally bounded, eventually leading to out-of-bounds I/O reads. Fix this by breaking out of the loop immediately upon a partial copy_to_user(). A partial copy indicates a faulty user buffer, making subsequent read attempts futile. Breaking out ensures we return the number of successfully read bytes without risking out-of-bounds hardware accesses in subsequent mismatched iterations.