[PATCH AUTOSEL 5.10 30/39] net: ipconfig: Don't override command-line hostnames or domains
From: Sasha Levin <sashal@kernel.org>
Date: 2021-06-07 16:18:08
Also in:
lkml, netdev
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
From: Josh Triplett <josh@joshtriplett.org> [ Upstream commit b508d5fb69c2211a1b860fc058aafbefc3b3c3cd ] If the user specifies a hostname or domain name as part of the ip= command-line option, preserve it and don't overwrite it with one supplied by DHCP/BOOTP. For instance, ip=::::myhostname::dhcp will use "myhostname" rather than ignoring and overwriting it. Fix the comment on ic_bootp_string that suggests it only copies a string "if not already set"; it doesn't have any such logic. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> --- net/ipv4/ipconfig.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index 3cd13e1bc6a7..213a1c91507d 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c@@ -870,7 +870,7 @@ static void __init ic_bootp_send_if(struct ic_device *d, unsigned long jiffies_d /* - * Copy BOOTP-supplied string if not already set. + * Copy BOOTP-supplied string */ static int __init ic_bootp_string(char *dest, char *src, int len, int max) {
@@ -919,12 +919,15 @@ static void __init ic_do_bootp_ext(u8 *ext) } break; case 12: /* Host name */ - ic_bootp_string(utsname()->nodename, ext+1, *ext, - __NEW_UTS_LEN); - ic_host_name_set = 1; + if (!ic_host_name_set) { + ic_bootp_string(utsname()->nodename, ext+1, *ext, + __NEW_UTS_LEN); + ic_host_name_set = 1; + } break; case 15: /* Domain name (DNS) */ - ic_bootp_string(ic_domain, ext+1, *ext, sizeof(ic_domain)); + if (!ic_domain[0]) + ic_bootp_string(ic_domain, ext+1, *ext, sizeof(ic_domain)); break; case 17: /* Root path */ if (!root_server_path[0])
--
2.30.2