{"id":153472,"date":"2026-01-09T11:12:29","date_gmt":"2026-01-09T09:12:29","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/vosstanovlen-kod-unixv4-pervoj-os-s-yadrom-na-yazyke-c-uyazvimost-v-unixv4"},"modified":"2026-01-09T11:12:29","modified_gmt":"2026-01-09T09:12:29","slug":"vosstanovlen-kod-unixv4-pervoj-os-s-yadrom-na-yazyke-c-uyazvimost-v-unixv4","status":"publish","type":"post","link":"https:\/\/prohoster.info\/en\/blog\/news\/vosstanovlen-kod-unixv4-pervoj-os-s-yadrom-na-yazyke-c-uyazvimost-v-unixv4","title":{"rendered":"The UNIXv4 code, the first OS with a kernel written in C, has been restored. Vulnerability in UNIXv4.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"
At the end of last year, during maintenance at the University of Utah's data center, an archived magnetic tape containing the UNIXv4 operating system code was discovered. This system was developed in 1973 for the PDP-11\/45 and was considered lost. UNIXv4 continued the evolution of the UNIXv3 operating system, released a year earlier, which was the first to implement the C programming language and unnamed pipes. A unique feature of UNIXv4 was the rewriting of the kernel from assembly language to C. The UNIXv4 kernel code was written by Ken Thompson, while the drivers were created by Dennis Ritchie. <\/p>\n
At the end of December 2025, museum staff specializing in the history of computing managed to find the necessary equipment and extract the preserved archive from the tape. The readtape toolkit was used to digitize the recorded analog signal, and efforts developed during the recovery of the Emacs editor archive by James Gosling were employed to decode the archive format. <\/p>\n
In addition to the UNIXv4 code, the tape also contained the source texts of one of the first compilers for the C language and the SNOBOL language interpreter. Later, the UNIXv4 code was tidied up and published on GitHub in a form suitable for building and running in a PDP-11 simulator. The UNIXv4 code comprises 61,000 lines, with 27,000 in C, 33,000 in assembly for the PDP-11, and about 1,000 in header files.
<\/center> <\/p>\n
One of the security researchers noted the 'su' utility that was included in UNIXv4. This utility consisted of fewer than 50 lines of code, was installed with the setuid-root flag, and allowed the execution of \/bin\/sh with root privileges upon entering the correct password. The code contained a vulnerability that led to a buffer overflow due to copying the user-input password into a fixed 100-character array without checking the size of the input data. <\/p>\n
The identified issue was commented on by 93-year-old Douglas McIlroy, who was part of the original Unix development team at Bell Labs, suggesting the concept of unnamed pipes and creating utilities such as echo, spell, diff, sort, join, and tr. According to Douglas, before the Morris worm in 1988, very few people paid attention to buffer overflows. Adding checks for the size of manually entered data was seen as adding unnecessary code, and crashing upon overflow was viewed as an awkward form of handling incorrect input. Over time, overflows occurring from processing automatically generated strings began to be fixed, but for manual input, the logic was at the level of 'who would need to manually enter too long strings?'. \n Source: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"
![\"The](\"\/wp-content\/uploads\/2026\/01\/f20da03c94b8a3a772fc39a048875f05.png\")
<\/center> <\/p>\n