netserver: do not chmod("/dev/null", 0644) when suppress_debug==1 #63
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…fault).
When running as root, chmod("/dev/null", 0644) will break most Unix-like
systems as "/dev/null" can't be open for write by non-root users anymore.
Before the fix:
root@linux# strace -f -e chmod ./netserver
Starting netserver with host 'IN(6)ADDR_ANY' port '12865' and family AF_UNSPEC
strace: Process 976220 attached
[pid 976219] +++ exited with 0 +++
chmod("/dev/null", 0644) = 0
Fixes: 5380b1f ("netserver: use mkstemp to create/open debug file")
jpbrucker
reviewed
Jan 12, 2022
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Same as #27
I just ran into a related problem: when exiting netserver, we actually remove /dev/null!
if (buf.st_size == 0) unlink(FileName);
I noticed this when launching netserver from inetd as root, /dev/null just disappears after the first netperf run. Probably not a good idea to run as root, I fixed my config now but others will run into this. Would you like to fix that one as well or shall I send a fix? I don't mind either way, I could also fix both.
| @@ -260,7 +260,10 @@ open_debug_file() | |||
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| #if !defined(WIN32) | |||
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| chmod(FileName,0644); | |||
| /* Only chmod() if FileName != "/dev/null" */ | |||
| if (strcmp(FileName, NETPERF_NULL)) { | |||
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may be simpler as `if (!suppress_debug)'
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When running as root, chmod("/dev/null", 0644) will break most Unix-like
systems as "/dev/null" can't be open for write by non-root users anymore.
Before the fix:
root@linux# strace -f -e chmod ./netserver
Starting netserver with host 'IN(6)ADDR_ANY' port '12865' and family AF_UNSPEC
strace: Process 976220 attached
[pid 976219] +++ exited with 0 +++
chmod("/dev/null", 0644) = 0
Fixes: 5380b1f ("netserver: use mkstemp to create/open debug file")