August 2012
Intermediate to advanced
624 pages
17h 11m
Polish
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14.2. Unikanie spoofingu w pracy interpretera
Problem
Chcemy uniknąć ataków z wykorzystaniem praw setuid i konta użytkownika root.
Rozwiązanie
W wywołaniu powłoki należy uwzględnić końcowy znak myślnika:
#!/bin/bash –
Analiza
Pierwszy wiersz skryptu ma szczególne znaczenie. Informuje on jądro systemu, którego interpretera należy użyć, aby właściwie przetworzyć pozostałą część pliku. Jądro uwzględnia również pojedynczą opcję dostarczaną do interpretera. Fakt ten jest wykorzystywany w niektórych rodzajach ataków. Jeżeli jednak wraz z plikiem wykonywalnym powłoki zostanie dostarczona odpowiednia opcja, ryzyko ataku nie występuje. Więcej informacji na ten temat znajduje się na stronie http://www.faqs.org/faqs/unix-faq/faq/part4/section-7.html.
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.