#39648 [Asn->Csd]: Implementation of PHP functions chown() and chgrp() not thread safe.

ID: 39648 Updated by: iliaa@php.net Reported By: wharmby at uk dot ibm dot com -Status: Assigned +Status: Closed Bug Type: Unknown/Other Function Operating System: Linux RHEL4 PHP Version: 5CVS-2006-11-27 (snap) Assigned To: iliaa New Comment: This bug has been fixed in CVS. Snapshots of the sources are packaged every three hours; this change will be in the next snapshot. You can grab the snapshot at http://snaps.php.net/. Thank you for the report, and for helping us make PHP better. Previous Comments: ------------------------------------------------------------------------ [2006-11-27 17:05:42] wharmby at uk dot ibm dot com Description: ------------ The current implementation of the chown() and chgrp() functions on Linux use the non-reentrant getpwnam() and getgrnam() C library calls respectively rather than the reentrant getpwnam_r() and getgrnam_r(). Therefore using either chown() or chgrp() on Linux in a ZTS enabled build could lead to unpredictable/undesirable results. The following patch, which was built against the latest snapshot (Nov 27th, 2006, 0730 GMT) modifies the code in ext/standard/filestat.c to use the reentrant versions of these functions and so make these 2 functions thread safe: http://pastebin.ca/259657 However, I am concerned that this patch relies on the C library supporting the POSIX.1 functions getpwnam_r(), getgrnam_r() and sysconf(). These are all implemented by GNU libc but are there other C libraries used to build PHP which may not have the necessary support ? Or is it reasonable to assume that all C libraries used when buiding PHP will be POSIX.1 compliant ? N.B There are other uses of these non-reentrant functions in the PHP code base (e.g posix.c and fopen_wrappers.c) and I m happy to produce the necessary patches to fix these uses if this fix proves satisfactory. Andy Wharmby IBM United Kingdom Limited Reproduce code: --------------- --------------- Problem found by code inspection. As with most thread safety issues difficult to produce a simple testcase which will show a reproducible crash but current Linux executable is clearly not reentrant. Expected result: ---------------- N/A Actual result: -------------- N/A ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=39648&edit=1