nextcloud

Tree: f3e6e0121d

Author	SHA1	Message	Date
Morris Jobke	f63915d0c8	update license headers and authors	9 years ago
Lukas Reschke	155ae44bc6	Fix collision on temporary files + adjust permissions This changeset hardens the temporary file and directory creation to address multiple problems that may lead to exposure of files to other users, data loss or other unexpected behaviour that is impossible to debug. [CWE-668: Exposure of Resource to Wrong Sphere](https://cwe.mitre.org/data/definitions/668.html) The temporary file and folder handling as implemented in ownCloud is performed using a MD5 hash over `time()` concatenated with `rand()`. This is insufficiently and leads to the following security problems: The generated filename could already be used by another user. It is not verified whether the file is already used and thus temporary files might be used for another user as well resulting in all possible stuff such as "user has file of other user". Effectively this leaves us with: 1. A timestamp based on seconds (no entropy at all) 2. `rand()` which returns usually a number between 0 and 2,147,483,647 Considering the birthday paradox and that we use this method quite often (especially when handling external storage) this is quite error prone and needs to get addressed. This behaviour has been fixed by using `tempnam` instead for single temporary files. For creating temporary directories an additional postfix will be appended, the solution is for directories still not absolutely bulletproof but the best I can think about at the moment. Improvement suggestions are welcome. [CWE-378: Creation of Temporary File With Insecure Permissions](https://cwe.mitre.org/data/definitions/378.html) Files were created using `touch()` which defaults to a permission of 0644. Thus other users on the machine may read potentially sensitive information as `/tmp/` is world-readable. However, ownCloud always encourages users to use a dedicated machine to run the ownCloud instance and thus this is no a high severe issue. Permissions have been adjusted to 0600. [CWE-379: Creation of Temporary File in Directory with Incorrect Permissions](https://cwe.mitre.org/data/definitions/379.html) Files were created using `mkdir()` which defaults to a permission of 0777. Thus other users on the machine may read potentially sensitive information as `/tmp/` is world-readable. However, ownCloud always encourages users to use a dedicated machine to run the ownCloud instance and thus this is no a high severe issue. Permissions have been adjusted to 0700.Please enter the commit message for your changes.	9 years ago
Lukas Reschke	9622fbdf29	Filter potential dangerous characters in path name We should not allow / or \ in the postfix here.	9 years ago
Jenkins for ownCloud	b585d87d9d	Update license headers	9 years ago
Olivier Paroz	f890c3ffb1	Make the method compatible with all types of extensions Fix existing tests	9 years ago
Olivier Paroz	8d6b2b8867	Keep the extension in temp files The file extension helps some applications like ImageMagick to properly process files	9 years ago
Morris Jobke	06aef4e8b1	Revert "Updating license headers" This reverts commit `6a1a4880f0`.	9 years ago
Jenkins for ownCloud	6a1a4880f0	Updating license headers	9 years ago
Robin Appelman	45e3cbefc9	Check directory handle before we use it	9 years ago
Robin Appelman	83c74b80ad	Add \OC\TempManager to handle creating and cleaning temporary files	9 years ago

11 Commits (f3e6e0121d8a86cf7a5782a2cc06295da221c56c)