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From 2ae1099a42e6a0f06de305ca13a842ac83d4683e Mon Sep 17 00:00:00 2001
From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Mon, 22 Apr 2019 23:17:27 +0200
Subject: [PATCH] xshared: check for maximum buffer length in
add_param_to_argv()
Bail out if we go over the boundary, based on patch from Sebastian.
Reported-by: Sebastian Neef <contact@0day.work>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Upstream-Status: Backport
CVE: CVE-2019-11360
Signed-off-by: Li Zhou <li.zhou@windriver.com>
---
iptables/xshared.c | 46 ++++++++++++++++++++++++++++------------------
1 file changed, 28 insertions(+), 18 deletions(-)
diff --git a/iptables/xshared.c b/iptables/xshared.c
index fb186fb1..36a2ec5f 100644
--- a/iptables/xshared.c
+++ b/iptables/xshared.c
@@ -433,10 +433,24 @@ void save_argv(void)
}
}
+struct xt_param_buf {
+ char buffer[1024];
+ int len;
+};
+
+static void add_param(struct xt_param_buf *param, const char *curchar)
+{
+ param->buffer[param->len++] = *curchar;
+ if (param->len >= sizeof(param->buffer))
+ xtables_error(PARAMETER_PROBLEM,
+ "Parameter too long!");
+}
+
void add_param_to_argv(char *parsestart, int line)
{
- int quote_open = 0, escaped = 0, param_len = 0;
- char param_buffer[1024], *curchar;
+ int quote_open = 0, escaped = 0;
+ struct xt_param_buf param = {};
+ char *curchar;
/* After fighting with strtok enough, here's now
* a 'real' parser. According to Rusty I'm now no
@@ -445,7 +459,7 @@ void add_param_to_argv(char *parsestart, int line)
for (curchar = parsestart; *curchar; curchar++) {
if (quote_open) {
if (escaped) {
- param_buffer[param_len++] = *curchar;
+ add_param(¶m, curchar);
escaped = 0;
continue;
} else if (*curchar == '\\') {
@@ -455,7 +469,7 @@ void add_param_to_argv(char *parsestart, int line)
quote_open = 0;
*curchar = '"';
} else {
- param_buffer[param_len++] = *curchar;
+ add_param(¶m, curchar);
continue;
}
} else {
@@ -471,36 +485,32 @@ void add_param_to_argv(char *parsestart, int line)
case ' ':
case '\t':
case '\n':
- if (!param_len) {
+ if (!param.len) {
/* two spaces? */
continue;
}
break;
default:
/* regular character, copy to buffer */
- param_buffer[param_len++] = *curchar;
-
- if (param_len >= sizeof(param_buffer))
- xtables_error(PARAMETER_PROBLEM,
- "Parameter too long!");
+ add_param(¶m, curchar);
continue;
}
- param_buffer[param_len] = '\0';
+ param.buffer[param.len] = '\0';
/* check if table name specified */
- if ((param_buffer[0] == '-' &&
- param_buffer[1] != '-' &&
- strchr(param_buffer, 't')) ||
- (!strncmp(param_buffer, "--t", 3) &&
- !strncmp(param_buffer, "--table", strlen(param_buffer)))) {
+ if ((param.buffer[0] == '-' &&
+ param.buffer[1] != '-' &&
+ strchr(param.buffer, 't')) ||
+ (!strncmp(param.buffer, "--t", 3) &&
+ !strncmp(param.buffer, "--table", strlen(param.buffer)))) {
xtables_error(PARAMETER_PROBLEM,
"The -t option (seen in line %u) cannot be used in %s.\n",
line, xt_params->program_name);
}
- add_argv(param_buffer, 0);
- param_len = 0;
+ add_argv(param.buffer, 0);
+ param.len = 0;
}
}
--
2.17.1
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