Do not crash when /etc/resolv.conf is immutable (bsc#1096142) #103
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lslezak
commented
Jun 14, 2018
lslezak
commented
- See https://bugzilla.suse.com/show_bug.cgi?id=1096142
- According to the reporter the system was gradually upgraded from 42.2 and uses some non-default settings (OpenDNS servers) so the bug should not affect many users => master should be enough
- 4.1.0
src/modules/RootPart.rb
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| @@ -1718,7 +1718,13 @@ def create_backup | |||
| # the network connection works for the chrooted scripts | |||
| def inject_intsys_files | |||
| # the original file is backed up and restored later | |||
| ::FileUtils.cp(RESOLV_CONF, File.join(Installation.destdir, RESOLV_CONF)) if File.exist?(RESOLV_CONF) | |||
| target = File.join(Installation.destdir, RESOLV_CONF) | |||
| ::FileUtils.cp(RESOLV_CONF, target) if File.exist?(RESOLV_CONF) | |||
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when we are touching it we should also check if resolv.conf is not just symlink like new network manager or systemd-resolver doing and in such case also do not touch it.
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Ummm, and will then the name resolution work in the /mnt chroot?
I mean when using standard wicked configration the resolv.conf looks like this if the system is not up:
### /etc/resolv.conf file autogenerated by netconfig!
#
# Before you change this file manually, consider to define the
# static DNS configuration using the following variables in the
# /etc/sysconfig/network/config file:
# NETCONFIG_DNS_STATIC_SEARCHLIST
# NETCONFIG_DNS_STATIC_SERVERS
# NETCONFIG_DNS_FORWARDER
# or disable DNS configuration updates via netconfig by setting:
# NETCONFIG_DNS_POLICY=''
#
# See also the netconfig(8) manual page and other documentation.
#
# Note: Manual change of this file disables netconfig too, but
# may get lost when this file contains comments or empty lines
# only, the netconfig settings are same with settings in this
# file and in case of a "netconfig update -f" call.
#
### Please remove (at least) this line when you modify the file!
So it's only an empty template and the name resolution will not work!
The question is how the other tools behave and whether the name resolution will work if we skip copying the file if a symlink is detected.
We need the name resolution for the registration rollback, we basically run chroot /mnt SUSEConnect --rollback. With empty or invalid resolv.conf this won't work... 😟
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I understand when you overwrite file, but I have to be sure that when you do backup it respect symlink and also in this case that cp never write to symlink target.
try this in shell ( scenario we have to avoid ):
jreidinger@linux-vvcf:/tmp> touch a
jreidinger@linux-vvcf:/tmp> ln -s a b
jreidinger@linux-vvcf:/tmp> cat a
jreidinger@linux-vvcf:/tmp> cat b
jreidinger@linux-vvcf:/tmp> echo "test" > c
jreidinger@linux-vvcf:/tmp> cp c b
jreidinger@linux-vvcf:/tmp> cat a
test
jreidinger@linux-vvcf:/tmp> cat b
test
test/root_part_test.rb
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| end | ||
| end | ||
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| context "resolf.conf does not exist in inst-sys" do |
test/root_part_test.rb
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| allow(Yast::Installation).to receive(:destdir).and_return("/mnt") | ||
| end | ||
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| context "resolf.conf exists in inst-sys" do |
test/root_part_test.rb
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| allow(FileUtils).to receive(:cp) | ||
| end | ||
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| it "copies the resolf.conf from inst-sys to the target" do |
test/root_part_test.rb
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| expect(File).to receive(:exist?).with("/etc/resolv.conf").and_return(false) | ||
| end | ||
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| it "does not copy the resolf.conf" do |
