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11.4 Security Considerations for locate

11.4.1 Race Conditions

It is fairly unusual for the output of locate to be fed into another command. However, if this were to be done, this would raise the same set of security issues as the use of ‘find ... -print’. Although the problems relating to whitespace in file names can be resolved by using locate's ‘-0’ option, this still leaves the race condition problems associated with ‘find ... -print0’. There is no way to avoid these problems in the case of locate.

11.4.2 Long File Name Bugs with Old-Format Databases

Old versions of locate have a bug in the way that old-format databases are read. This bug affects the following versions of locate:

  1. All releases prior to 4.2.31
  2. All 4.3.x releases prior to 4.3.7

The affected versions of locate read file names into a fixed-length 1026 byte buffer, allocated on the heap. This buffer is not extended if file names are too long to fit into the buffer. No range checking on the length of the filename is performed. This could in theory lead to a privilege escalation attack. Findutils versions 4.3.0 to 4.3.6 are also affected.

On systems using the old database format and affected versions of locate, carefully-chosen long file names could in theory allow malicious users to run code of their choice as any user invoking locate.

If remote users can choose the names of files stored on your system, and these files are indexed by updatedb, this may be a remote security vulnerability. Findutils version 4.2.31 and findutils version 4.3.7 include fixes for this problem. The updatedb, bigram and code programs do no appear to be affected.

If you are also using GNU coreutils, you can use the following command to determine the length of the longest file name on a given system:

     find / -print0 | tr -c '\0' 'x' | tr '\0' '\n' | wc -L

Although this problem is significant, the old database format is not the default, and use of the old database format is not common. Most installations and most users will not be affected by this problem.