Low hanging fruit, vulnerability

[will-or3]

/src/shell/shell.c
Line 24

You increment the array by -1 (i--)
But you don't do any bounds check
Which could let a user backspace into a negative buffer

Buffer[-i] <- oob memory write

My fix, add bounds checking

void shell_read_line(char buf[], size_t size) {
    size_t i = 0;
    char ch;

    while ((ch = shell_read_char())) {
        if (ch == '\b') {
            if (i > 0) {
                i--;   // prevent underflow
            }
        } else {
            if (i < size - 1) {
                buf[i++] = ch;  // prevent overflow
            }
        }
    }
    buf[i] = '\0';
}