[PATCH 1/3] iptables: fix error reporting with wrong/missing arguments

[PATCH 1/3] iptables: fix error reporting with wrong/missing arguments

[Pablo Neira Ayuso]

This patch fixes wrong error reporting when arguments are missing:

# iptables -I INPUT -m state --state
iptables v1.4.2-rc1: Unknown arg `(null)'
Try `iptables -h' or 'iptables --help' for more information.

or wrong:

# iptables -I INPUT -m state --xyz
iptables v1.4.2-rc1: Unknown arg `(null)'
Try `iptables -h' or 'iptables --help' for more information.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---

 ip6tables.c |   19 ++++++++++++++++++-
 iptables.c  |   19 ++++++++++++++++++-
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/ip6tables.c b/ip6tables.c
index 12298ca..9ce1074 100644
--- a/ip6tables.c
+++ b/ip6tables.c
@@ -1888,9 +1888,26 @@ int do_command6(int argc, char *argv[], char **table, ip6tc_handle_t *handle)
 					continue;
 				}
 
-				if (!m)
+				if (!m) {
+					if (c == '?') {
+						if (optopt) {
+							exit_error(
+							   PARAMETER_PROBLEM,
+							   "option `%s' "
+							   "requires an "
+							   "argument",
+							   argv[optind-1]);
+						} else {
+							exit_error(
+							   PARAMETER_PROBLEM,
+							   "unknown option "
+							   "`%s'",
+							   argv[optind-1]);
+						}
+					}
 					exit_error(PARAMETER_PROBLEM,
 						   "Unknown arg `%s'", optarg);
+				}
 			}
 		}
 		invert = FALSE;
diff --git a/iptables.c b/iptables.c
index b927a11..d2b9081 100644
--- a/iptables.c
+++ b/iptables.c
@@ -1909,9 +1909,26 @@ int do_command(int argc, char *argv[], char **table, iptc_handle_t *handle)
 					optind--;
 					continue;
 				}
-				if (!m)
+				if (!m) {
+					if (c == '?') {
+						if (optopt) {
+							exit_error(
+							   PARAMETER_PROBLEM,
+							   "option `%s' "
+							   "requires an "
+							   "argument",
+							   argv[optind-1]);
+						} else {
+							exit_error(
+							   PARAMETER_PROBLEM,
+							   "unknown option "
+							   "`%s'",
+							   argv[optind-1]);
+						}
+					}
 					exit_error(PARAMETER_PROBLEM,
 						   "Unknown arg `%s'", optarg);
+				}
 			}
 		}
 		invert = FALSE;

[PATCH 2/3] state: report spaces in the state list parsing

[Pablo Neira Ayuso]

This patch adds better error reporting when the user inserts a space
between two states with the --state option.

iptables -I INPUT -m state ESTABLISHED, RELATED
                                       ^
				  mind the space

results in:

iptables v1.4.2-rc1: Bad state `'
Try `iptables -h' or 'iptables --help' for more information.

Now this returns:

iptables v1.4.2-rc1: `--state' requires a list of states with no
spaces, e.g. ESTABLISHED,RELATED

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---

 extensions/libxt_state.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/extensions/libxt_state.c b/extensions/libxt_state.c
index 3af2e48..ae8ae7b 100644
--- a/extensions/libxt_state.c
+++ b/extensions/libxt_state.c
@@ -54,7 +54,10 @@ state_parse_states(const char *arg, struct xt_state_info *sinfo)
 			exit_error(PARAMETER_PROBLEM, "Bad state `%s'", arg);
 		arg = comma+1;
 	}
-
+	if (!*arg)
+		exit_error(PARAMETER_PROBLEM, "`--state' requires a list of "
+					      "states with no spaces, e.g. "
+					      "ESTABLISHED,RELATED");
 	if (strlen(arg) == 0 || !state_parse_state(arg, strlen(arg), sinfo))
 		exit_error(PARAMETER_PROBLEM, "Bad state `%s'", arg);
 }

[PATCH 3/3] iptables: refer to dmesg when we hit error

[Pablo Neira Ayuso]

This does not make any better, but at least refer to
dmesg which is the common source of information to diagnose
kernel-side problems. This is helpful for newbie users.

# iptables -I INPUT -j CLUSTERIP
iptables: Invalid argument. Run `dmesg' for more information.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---

 ip6tables-standalone.c |    3 ++-
 iptables-standalone.c  |    3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/ip6tables-standalone.c b/ip6tables-standalone.c
index 5bdcd4f..6c20bd8 100644
--- a/ip6tables-standalone.c
+++ b/ip6tables-standalone.c
@@ -70,7 +70,8 @@ main(int argc, char *argv[])
 		ret = ip6tc_commit(&handle);
 
 	if (!ret)
-		fprintf(stderr, "ip6tables: %s\n",
+		fprintf(stderr, "ip6tables: %s. "
+				"Run `dmesg' for more information.\n",
 			ip6tc_strerror(errno));
 
 	exit(!ret);
diff --git a/iptables-standalone.c b/iptables-standalone.c
index 55d9bbe..630c586 100644
--- a/iptables-standalone.c
+++ b/iptables-standalone.c
@@ -71,7 +71,8 @@ main(int argc, char *argv[])
 		ret = iptc_commit(&handle);
 
 	if (!ret) {
-		fprintf(stderr, "iptables: %s\n",
+		fprintf(stderr, "iptables: %s. "
+				"Run `dmesg' for more information.\n",
 			iptc_strerror(errno));
 		if (errno == EAGAIN) {
 			exit(RESOURCE_PROBLEM);

Re: [PATCH 1/3] iptables: fix error reporting with wrong/missing arguments

[Jan Engelhardt]

On Wednesday 2008-11-19 00:43, Pablo Neira Ayuso wrote:
>@@ -1888,9 +1888,26 @@ int do_command6(int argc, char *argv[], char **table, ip6tc_handle_t *handle)
> 					continue;
> 				}
> 
>-				if (!m)
>+				if (!m) {
>+					if (c == '?') {
>+						if (optopt) {
>+							exit_error(
>+							   PARAMETER_PROBLEM,
>+							   "option `%s' "
>+							   "requires an "
>+							   "argument",
>+							   argv[optind-1]);
>+						} else {
>+							exit_error(
>+							   PARAMETER_PROBLEM,
>+							   "unknown option "
>+							   "`%s'",
>+							   argv[optind-1]);
>+						}
>+					}
> 					exit_error(PARAMETER_PROBLEM,
> 						   "Unknown arg `%s'", optarg);
>+				}

I think it is time to give attention to CodingStyle section 1:

	“The answer to that is that if you need more than 3 levels of
	indentation, you're screwed anyway, and should fix your
	program.”

Maybe this could be put into a separate function somehow than trying
to squeeze everything between colums 64 and 80?
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Re: [PATCH 2/3] state: report spaces in the state list parsing

[Jan Engelhardt]

On Wednesday 2008-11-19 00:43, Pablo Neira Ayuso wrote:

>Now this returns:
>
>iptables v1.4.2-rc1: `--state' requires a list of states with no
>spaces, e.g. ESTABLISHED,RELATED
>
>Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
>---
>
> extensions/libxt_state.c |    5 ++++-
> 1 files changed, 4 insertions(+), 1 deletions(-)

This also needs to be done for libxt_conntrack.c I guess.

Re: [PATCH 1/3] iptables: fix error reporting with wrong/missing arguments

[Pablo Neira Ayuso]

Jan Engelhardt wrote:
> On Wednesday 2008-11-19 00:43, Pablo Neira Ayuso wrote:
>> @@ -1888,9 +1888,26 @@ int do_command6(int argc, char *argv[], char **table, ip6tc_handle_t *handle)
>> 					continue;
>> 				}
>>
>> -				if (!m)
>> +				if (!m) {
>> +					if (c == '?') {
>> +						if (optopt) {
>> +							exit_error(
>> +							   PARAMETER_PROBLEM,
>> +							   "option `%s' "
>> +							   "requires an "
>> +							   "argument",
>> +							   argv[optind-1]);
>> +						} else {
>> +							exit_error(
>> +							   PARAMETER_PROBLEM,
>> +							   "unknown option "
>> +							   "`%s'",
>> +							   argv[optind-1]);
>> +						}
>> +					}
>> 					exit_error(PARAMETER_PROBLEM,
>> 						   "Unknown arg `%s'", optarg);
>> +				}
> 
> I think it is time to give attention to CodingStyle section 1:
> 
> 	“The answer to that is that if you need more than 3 levels of
> 	indentation, you're screwed anyway, and should fix your
> 	program.”
> 
> Maybe this could be put into a separate function somehow than trying
> to squeeze everything between colums 64 and 80?

Putting this code into a function will not make any better for the whole
section of code under the "default" tag in the switch - which is indeed
already horrible as it looks like a real Spanish chorizo [1].

Of course, you are free to send a patch to cleanup not only this part,
but the whole default section of the switch. I'd be please to apply it.

[1] http://en.wikipedia.org/wiki/Chorizo

-- 
"Los honestos son inadaptados sociales" -- Les Luthiers
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Re: [PATCH 2/3] state: report spaces in the state list parsing

[Pablo Neira Ayuso]

[-- Attachment #1: Type: text/plain, Size: 541 bytes --]

Jan Engelhardt wrote:
> On Wednesday 2008-11-19 00:43, Pablo Neira Ayuso wrote:
> 
>> Now this returns:
>>
>> iptables v1.4.2-rc1: `--state' requires a list of states with no
>> spaces, e.g. ESTABLISHED,RELATED
>>
>> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
>> ---
>>
>> extensions/libxt_state.c |    5 ++++-
>> 1 files changed, 4 insertions(+), 1 deletions(-)
> 
> This also needs to be done for libxt_conntrack.c I guess.

Thanks for the spot, new patch attached.

-- 
"Los honestos son inadaptados sociales" -- Les Luthiers

[-- Attachment #2: fix-state-parsing.patch --]
[-- Type: text/x-diff, Size: 2061 bytes --]

state: report spaces in the state list parsing

From: Pablo Neira Ayuso <pablo@netfilter.org>

This patch adds better error reporting when the user inserts a space
between two states with the --state option.

iptables -I INPUT -m state ESTABLISHED, RELATED
                                       ^
				  mind the space

results in:

iptables v1.4.2-rc1: Bad state `'
Try `iptables -h' or 'iptables --help' for more information.

Now this returns:

iptables v1.4.2-rc1: `--state' requires a list of states with no
spaces, e.g. ESTABLISHED,RELATED

This patch also applies to libxt_conntrack which has a copy of the
function.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---

 extensions/libxt_conntrack.c |    5 ++++-
 extensions/libxt_state.c     |    5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)


diff --git a/extensions/libxt_conntrack.c b/extensions/libxt_conntrack.c
index 79ed3b8..5f3257c 100644
--- a/extensions/libxt_conntrack.c
+++ b/extensions/libxt_conntrack.c
@@ -107,7 +107,10 @@ parse_states(const char *arg, struct xt_conntrack_info *sinfo)
 			exit_error(PARAMETER_PROBLEM, "Bad ctstate `%s'", arg);
 		arg = comma+1;
 	}
-
+	if (!*arg)
+		exit_error(PARAMETER_PROBLEM, "`--ctstate' requires a list of "
+					      "states with no spaces, e.g. "
+					      "ESTABLISHED,RELATED");
 	if (strlen(arg) == 0 || !parse_state(arg, strlen(arg), sinfo))
 		exit_error(PARAMETER_PROBLEM, "Bad ctstate `%s'", arg);
 }
diff --git a/extensions/libxt_state.c b/extensions/libxt_state.c
index 3af2e48..ae8ae7b 100644
--- a/extensions/libxt_state.c
+++ b/extensions/libxt_state.c
@@ -54,7 +54,10 @@ state_parse_states(const char *arg, struct xt_state_info *sinfo)
 			exit_error(PARAMETER_PROBLEM, "Bad state `%s'", arg);
 		arg = comma+1;
 	}
-
+	if (!*arg)
+		exit_error(PARAMETER_PROBLEM, "`--state' requires a list of "
+					      "states with no spaces, e.g. "
+					      "ESTABLISHED,RELATED");
 	if (strlen(arg) == 0 || !state_parse_state(arg, strlen(arg), sinfo))
 		exit_error(PARAMETER_PROBLEM, "Bad state `%s'", arg);
 }