no EINTR check on flock(LOCK_EX)
| Bug #66623 | no EINTR check on flock(LOCK_EX) | ||||
|---|---|---|---|---|---|
| Submitted: | 2014-02-01 08:48 UTC | Modified: | 2014-12-10 22:49 UTC | ||
| From: | php at bof dot de | Assigned: | yohgaki (profile) | ||
| Status: | Closed | Package: | Session related | ||
| PHP Version: | 5.6.0alpha1 | OS: | |||
| Private report: | No | CVE-ID: | None | ||
[2014-02-01 08:48 UTC] php at bof dot de
Description: ------------ Noticed a problem in ext/session/mod_files.c : > Some syscalls can fail with EINTR, when a signal hits while within the > kernel. This is especially true for flock(LOCK_EX) because in the > already-locked case the second call will go to sleep for a while waiting > for the lock to clear. But it is also possible, I think, for the > pread/read/write calls. The usual handling for the case (-1 return && > errno > == EINTR) is to just repeat the call in a while loop. I think that at > least > doing so for the LOCK_EX calls, would be prudent. Re-Read the manpage (*) a bit... read/pread/write should be safe here, going to disk, and not a pipe or socket. But flock() will return EINTR when signalled and the signal handler did not use SA_RESTART. Most PHP execution will _probably_ okay anyway as $restart_syscalls is default true for pcntl_signal(), but handling would be safer anyway.
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[2014-12-10 22:49 UTC] yohgaki@php.net