udhcpc: make hostname sanitization optional. Closes 3979

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 15 insertions, 0 deletions

diff --git a/networking/udhcp/Config.src b/networking/udhcp/Config.src
index 6bfa398ea..c34c8d6f0 100644
--- a/networking/udhcp/Config.src
+++ b/networking/udhcp/Config.src
@@ -84,6 +84,17 @@ config FEATURE_UDHCPC_ARPING
           will DHCPDECLINE the offer if the address is in use,
           and restart the discover process.
 
+config FEATURE_UDHCPC_SANITIZEOPT
+        bool "Do not pass malformed host and domain names"
+        default y
+        depends on UDHCPC
+        help
+          If selected, udhcpc will check some options (such as option 12 -
+          hostname) and if they don't look like valid hostnames
+          (for example, if they start with dash or contain spaces),
+          they will be replaced with string "bad" when exporting
+          to the environment.
+
 config FEATURE_UDHCP_PORT
         bool "Enable '-P port' option for udhcpd and udhcpc"
         default n
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index 7dfc160e2..e468b7bbb 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -136,6 +136,7 @@ static int mton(uint32_t mask)
         return i;
 }
 
+#if ENABLE_FEATURE_UDHCPC_SANITIZEOPT
 /* Check if a given label represents a valid DNS label
  * Return pointer to the first character after the label upon success,
  * NULL otherwise.
@@ -192,6 +193,9 @@ static int good_hostname(const char *name)
                 name++;
         }
 }
+#else
+# define good_hostname(name) 1
+#endif
 
 /* Create "opt_name=opt_value" string */
 static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_optflag *optflag, const char *opt_name)