Security
On Unix, a setuid program is given an environment chosen by its caller, but it runs with different authority from its caller. The dynamic linker will usually load code from locations specified by the environment variables LD_LIBRARY_PATH and LD_PRELOAD and run it with the process's authority. If a setuid program did this, it would be insecure, because its caller could get it to run arbitrary code and hence misuse its authority. For this reason, libc unsets these environment variables at startup in a setuid process. setuid programs usually unset unknown environment variables and check others or set them to reasonable values.
Read more about this topic: Environment Variable
Famous quotes containing the word security:
“The most disgusting cad in the world is the man who, on grounds of decorum and morality, avoids the game of love. He is one who puts his own ease and security above the most laudable of philanthropies.”
—H.L. (Henry Lewis)
“Modern children were considerably less innocent than parents and the larger society supposed, and postmodern children are less competent than their parents and the society as a whole would like to believe. . . . The perception of childhood competence has shifted much of the responsibility for child protection and security from parents and society to children themselves.”
—David Elkind (20th century)
“...I lost myself in my work and never felt that marriage would give me the security I wanted. I thought that through the trade union movement we working women could get better conditions and security of mind.”
—Mary Anderson (1872–1964)