From efb8f104502c0d8efcd45101a767225042ef21d3 Mon Sep 17 00:00:00 2001
From: Brian Haley <haleyb.dev@gmail.com>
Date: Thu, 23 Jan 2025 18:26:45 -0500
Subject: [PATCH] Fix potential memory leak

When a new IPv6 address is being added to a dhcp_config
struct, if there is anything invalid regarding the prefix
it looks like there is a potential memory leak.
ret_err_free() should be used to free it.

Also, the new addrlist struct is being linked into
the existing addr6 list in the dhcp_config before the
validity check, it is best to defer this insertion
until later so an invalid entry is not present, since
the CONFIG_ADDR6 flag might not have been set yet.

Signed-off-by: Brian Haley <haleyb.dev@gmail.com>

Reference:https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=efb8f104502c0d8efcd45101a767225042ef21d3
Conflict:NA

---
 src/option.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/option.c b/src/option.c
index 16afb13..f3dee87 100644
--- a/src/option.c
+++ b/src/option.c
@@ -4043,10 +4043,8 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 		      }
 
 		    new_addr = opt_malloc(sizeof(struct addrlist));
-		    new_addr->next = new->addr6;
 		    new_addr->flags = 0;
 		    new_addr->addr.addr6 = in6;
-		    new->addr6 = new_addr;
 		    
 		    if (pref)
 		      {
@@ -4057,7 +4055,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 			    ((((u64)1<<(128-new_addr->prefixlen))-1) & addrpart) != 0)
 			  {
 			    dhcp_config_free(new);
-			    ret_err(_("bad IPv6 prefix"));
+			    ret_err_free(_("bad IPv6 prefix"), new_addr);
 			  }
 			
 			new_addr->flags |= ADDRLIST_PREFIX;
@@ -4071,6 +4069,8 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 		    if (i == 8)
 		      new_addr->flags |= ADDRLIST_WILDCARD;
 		    
+		    new_addr->next = new->addr6;
+		    new->addr6 = new_addr;
 		    new->flags |= CONFIG_ADDR6;
 		  }
 #endif
-- 
2.33.0