ipconfig: Correctly initialise ic_nameservers
[ Upstream commit 300eec7c0a
]
ic_nameservers, which stores the list of name servers discovered by
ipconfig, is initialised (i.e. has all of its elements set to NONE, or
0xffffffff) by ic_nameservers_predef() in the following scenarios:
- before the "ip=" and "nfsaddrs=" kernel command line parameters are
parsed (in ip_auto_config_setup());
- before autoconfiguring via DHCP or BOOTP (in ic_bootp_init()), in
order to clear any values that may have been set after parsing "ip="
or "nfsaddrs=" and are no longer needed.
This means that ic_nameservers_predef() is not called when neither "ip="
nor "nfsaddrs=" is specified on the kernel command line. In this
scenario, every element in ic_nameservers remains set to 0x00000000,
which is indistinguishable from ANY and causes pnp_seq_show() to write
the following (bogus) information to /proc/net/pnp:
#MANUAL
nameserver 0.0.0.0
nameserver 0.0.0.0
nameserver 0.0.0.0
This is potentially problematic for systems that blindly link
/etc/resolv.conf to /proc/net/pnp.
Ensure that ic_nameservers is also initialised when neither "ip=" nor
"nfsaddrs=" are specified by calling ic_nameservers_predef() in
ip_auto_config(), but only when ip_auto_config_setup() was not called
earlier. This causes the following to be written to /proc/net/pnp, and
is consistent with what gets written when ipconfig is configured
manually but no name servers are specified on the kernel command line:
#MANUAL
Signed-off-by: Chris Novakovic <chris@chrisn.me.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
parent
18a48a7a44
commit
e660508795
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@ -781,6 +781,11 @@ static void __init ic_bootp_init_ext(u8 *e)
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*/
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static inline void __init ic_bootp_init(void)
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{
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/* Re-initialise all name servers to NONE, in case any were set via the
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* "ip=" or "nfsaddrs=" kernel command line parameters: any IP addresses
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* specified there will already have been decoded but are no longer
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* needed
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*/
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ic_nameservers_predef();
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dev_add_pack(&bootp_packet_type);
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@ -1402,6 +1407,13 @@ static int __init ip_auto_config(void)
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int err;
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unsigned int i;
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/* Initialise all name servers to NONE (but only if the "ip=" or
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* "nfsaddrs=" kernel command line parameters weren't decoded, otherwise
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* we'll overwrite the IP addresses specified there)
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*/
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if (ic_set_manually == 0)
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ic_nameservers_predef();
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#ifdef CONFIG_PROC_FS
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proc_create("pnp", S_IRUGO, init_net.proc_net, &pnp_seq_fops);
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#endif /* CONFIG_PROC_FS */
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@ -1622,6 +1634,7 @@ static int __init ip_auto_config_setup(char *addrs)
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return 1;
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}
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/* Initialise all name servers to NONE */
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ic_nameservers_predef();
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/* Parse string for static IP assignment. */
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