Fixes the crash reported in Bugzilla #1131 where a malformed parameter that
specifies the table option during a restore can create an invalid pointer.
It was discovered during fuzz testing that options like '-ftf'
can cause a segfault. A parameter that includes a 't' is not currently
filtered correctly.

Improves the filtering to:
Filter a beginning '-' followed by a character other than '-' and then a 't'
anywhere in the parameter. This filters parameters like '-ftf'.
Filter '--table', stopping when the parameter length is reached. Because the
getopt_long function allows abbreviations, any unique abbreviation of '--table'
will be treated as '--table'. This filters parameters like '--t', '--ta', but 
not
'--ttl' or '--target'.

Signed-off-by: Oliver Ford <ojf...@gmail.com>
---
 iptables/ip6tables-restore.c | 5 +++--
 iptables/iptables-restore.c  | 5 +++--
 iptables/iptables-xml.c      | 6 +++---
 iptables/xtables-restore.c   | 5 +++--
 4 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/iptables/ip6tables-restore.c b/iptables/ip6tables-restore.c
index 39a881d..98e9c5f 100644
--- a/iptables/ip6tables-restore.c
+++ b/iptables/ip6tables-restore.c
@@ -165,8 +165,9 @@ static void add_param_to_argv(char *parsestart)
                        param_buffer[param_len] = '\0';
 
                        /* check if table name specified */
-                       if (!strncmp(param_buffer, "-t", 2)
-                            || !strncmp(param_buffer, "--table", 8)) {
+                       if ((param_buffer[0] == '-' && param_buffer[1] != '-' &&
+                               strchr(param_buffer, 't')) ||
+                               !strncmp(param_buffer, "--table", 
strlen(param_buffer))) {
                                xtables_error(PARAMETER_PROBLEM,
                                "The -t option (seen in line %u) cannot be "
                                "used in ip6tables-restore.\n", line);
diff --git a/iptables/iptables-restore.c b/iptables/iptables-restore.c
index 876fe06..c945745 100644
--- a/iptables/iptables-restore.c
+++ b/iptables/iptables-restore.c
@@ -162,8 +162,9 @@ static void add_param_to_argv(char *parsestart)
                        param_buffer[param_len] = '\0';
 
                        /* check if table name specified */
-                       if (!strncmp(param_buffer, "-t", 2)
-                           || !strncmp(param_buffer, "--table", 8)) {
+                       if ((param_buffer[0] == '-' && param_buffer[1] != '-' &&
+                               strchr(param_buffer, 't')) ||
+                               !strncmp(param_buffer, "--table", 
strlen(param_buffer))) {
                                xtables_error(PARAMETER_PROBLEM,
                                "The -t option (seen in line %u) cannot be "
                                "used in iptables-restore.\n", line);
diff --git a/iptables/iptables-xml.c b/iptables/iptables-xml.c
index 2e093b5..de56138 100644
--- a/iptables/iptables-xml.c
+++ b/iptables/iptables-xml.c
@@ -819,9 +819,9 @@ iptables_xml_main(int argc, char *argv[])
                                        *(param_buffer + param_len) = '\0';
 
                                        /* check if table name specified */
-                                       if (!strncmp(param_buffer, "-t", 3)
-                                           || !strncmp(param_buffer,
-                                                       "--table", 8)) {
+                                       if ((param_buffer[0] == '-' && 
param_buffer[1] != '-' &&
+                                               strchr(param_buffer, 't')) ||
+                                               !strncmp(param_buffer, 
"--table", strlen(param_buffer))) {
                                                xtables_error(PARAMETER_PROBLEM,
                                                           "Line %u seems to 
have a "
                                                           "-t table option.\n",
diff --git a/iptables/xtables-restore.c b/iptables/xtables-restore.c
index 15824f0..642b07f 100644
--- a/iptables/xtables-restore.c
+++ b/iptables/xtables-restore.c
@@ -136,8 +136,9 @@ static void add_param_to_argv(char *parsestart)
                        param_buffer[param_len] = '\0';
 
                        /* check if table name specified */
-                       if (!strncmp(param_buffer, "-t", 2)
-                           || !strncmp(param_buffer, "--table", 8)) {
+                       if ((param_buffer[0] == '-' && param_buffer[1] != '-' &&
+                               strchr(param_buffer, 't')) ||
+                               !strncmp(param_buffer, "--table", 
strlen(param_buffer))) {
                                xtables_error(PARAMETER_PROBLEM,
                                "The -t option (seen in line %u) cannot be "
                                "used in xtables-restore.\n", line);
-- 
2.11.0

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