Buffer overflow arbitrary write in Renesas rcar_gen3_v2.5

Summary

Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in Renesas arm-trusted-firmware allows Local Execution of Code. This vulnerability is associated with program files https://github.Com/renesas-rcar/arm-trusted-firmware/blob/rcar_gen3_v2.5/drivers/renesas/common/io/i... https://github.Com/renesas-rcar/arm-trusted-firmware/blob/rcar_gen3_v2.5/drivers/renesas/common/io/io_rcar.C . In line 313 "addr_loaded_cnt" is checked not to be "CHECK_IMAGE_AREA_CNT" (5) or larger, this check does not halt the function. Immediately after (line 317) there will be an overflow in the buffer and the value of "dst" will be written to the area immediately after the buffer, which is "addr_loaded_cnt". This will allow an attacker to freely control the value of "addr_loaded_cnt" and thus control the destination of the write immediately after (line 318). The write in line 318 will then be fully controlled by said attacker, with whichever address and whichever value ("len") they desire.