Avoid to write linked path #14
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Fluentd usually uses predictable paths for dumping object information. However, if systemd manages fluentd, it will send a SIGCONT to fluentd when the managed service is stopped or restarted (see 'man systemd.kill'). Thus, if a malicious link(s) are in place in /tmp, the attack will eventually be triggered. Signed-off-by: Hiroshi Hatake <hatake@calyptia.com>
0666 is the default permission for Kernel.open. But it shouldn't be used because we should use minimal permission. If we use default permission for dumping target path, dangling linked file is provided for target path which shouldn't be created elevated parmission having file, that is, world-writable permitted file. Signed-off-by: Hiroshi Hatake <hatake@calyptia.com>
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@frsyuki Could you kindly take a look if you have a time? We think that maintainace of this gem is important for Fluentd community. |
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Currently, sigdump uses predictable path to write object dump.
But, in some circumstances, this implementation makes a vulnerability for dangling symlink attack.
And also,
Kernel.openshould use0644instead of0666(wolrd-writable permission).This will be also vulnerability part of dangling symlink attack.