The /tmp directory has the sticky bit (chmod +t) set.
The effect of the sticky bit is described as follows in "man 2 chmod":
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If the mode bit S_ISVTX (sticky bit) is set on a directory, files inside the directory can be renamed or removed only by the owner of the file, the owner of the directory, or a process with the OWNER privilege (even if the modes of the directory would otherwise allow such an operation).
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In other words, the sticky bit does exactly what it's documented to do.
The sticky bit is a basic filesystem feature: no special security levels are needed to use it. This has been possible to do from at least 11.00 onwards, but it has not been the factory default... until now.
Many programs can be abused by manipulating their temporary files. /tmp must be writeable by everyone, so the sticky bit (chmod 1777 /tmp) is recommended by security experts. Setting the sticky bit on /tmp and /var/tmp is either a default or a very common part of post-installation hardening procedures on many unix-style operating systems.
MK
MK
