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fix: keep every netmask of an @ipMatch prefix in the radix tree (2.x) #3671

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fix: keep every netmask of an @ipMatch prefix in the radix tree (2.x) #3671

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133 changes: 57 additions & 76 deletions apache2/msc_tree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -78,6 +78,8 @@
return node;
}

int TreeCheckData(TreePrefix *prefix, CPTData *prefix_data, unsigned int netmask);

CPTData *CPTCreateCPTData(unsigned char netmask, apr_pool_t *pool) {

CPTData *prefix_data = apr_palloc(pool, sizeof(CPTData));
Expand Down Expand Up @@ -249,51 +251,57 @@
return new_node;
}

int InsertNetmask(TreeNode *node, TreeNode *parent, TreeNode *new_node,
CPTTree *tree, unsigned char netmask, unsigned char bitlen) {
/*
* Adds a netmask to a node, keeping the array sorted from the most to the
* least specific netmask. The array is grown (copied), not replaced, so the
* netmasks already on the node survive (#3588).
*/
int CPTAddNetmask(TreeNode *node, unsigned char netmask, apr_pool_t *pool) {
unsigned char *netmasks;
int i;

if (netmask != NETMASK_256-1 && netmask != NETMASK_128) {
if ((netmask != NETMASK_32 || (netmask == NETMASK_32 && bitlen != NETMASK_32))) {

node = new_node;
parent = new_node->parent;
netmasks = apr_palloc(pool, (node->count + 1) * sizeof(unsigned char));
if (netmasks == NULL)
return 0;
if (node->count > 0)
memcpy(netmasks, node->netmasks, node->count * sizeof(unsigned char));

while (parent != NULL && netmask < (parent->bit + 1)) {
node = parent;
parent = parent->parent;
}
i = node->count - 1;
while (i >= 0 && netmasks[i] < netmask) {
netmasks[i + 1] = netmasks[i];
i--;
}
netmasks[i + 1] = netmask;

node->count++;
node->netmasks = apr_palloc(tree->pool, (node->count * sizeof(unsigned char)));
node->netmasks = netmasks;
node->count++;

if(node->netmasks == NULL)
return 0;
if ((node->count-1) == 0) {
node->netmasks[0] = netmask;
return 1;
}
return 1;
}

node->netmasks[node->count - 1] = netmask;
/*
* Registers a netmask on the node that covers it: starting from new_node,
* walk up while the netmask is wider than the parent's branching bit.
*/
int InsertNetmask(TreeNode *node, TreeNode *parent, TreeNode *new_node,
CPTTree *tree, unsigned char netmask, unsigned char bitlen) {
if (netmask == NETMASK_256-1 || netmask == NETMASK_128)
return 0;
if (netmask == NETMASK_32 && bitlen == NETMASK_32)
return 0;

i = node->count - 2;
while (i >= 0) {
if (netmask < node->netmasks[i]) {
node->netmasks[i + 1] = netmask;
break;
}
node = new_node;
parent = new_node->parent;

node->netmasks[i + 1] = node->netmasks[i];
node->netmasks[i] = netmask;
i--;
}
}
while (parent != NULL && netmask < (parent->bit + 1)) {
node = parent;
parent = parent->parent;
}

return 0;
return CPTAddNetmask(node, netmask, tree->pool);
}

TreeNode *CPTAddElement(unsigned char *ipdata, unsigned int ip_bitmask, CPTTree *tree, unsigned char netmask) {

Check failure on line 304 in apache2/msc_tree.c

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SonarQubeCloud / SonarCloud Code Analysis

Refactor this function to reduce its Cognitive Complexity from 84 to the 25 allowed. 


See more on https://sonarcloud.io/project/issues?id=owasp-modsecurity_ModSecurity&issues=AaE1RdL3VPUT6YxDaeVw&open=AaE1RdL3VPUT6YxDaeVw&pullRequest=3671
unsigned char *buffer = NULL;
unsigned char bitlen = 0;
int bit_validation = 0, test_bit = 0;
Expand Down Expand Up @@ -388,52 +396,21 @@

if (test_bit == bitlen && node->bit == bitlen) {
if (node->prefix != NULL) {
int found = 0;
CPTData *prefix_data = NULL;

prefix_data = node->prefix->prefix_data;

while(prefix_data != NULL) {
if (prefix_data->netmask == netmask)
++found;
prefix_data = prefix_data->next;
}

if (found != 0) {

/*
* Same key already in the tree (e.g. 10.0.0.0/16 and then
* 10.0.0.0/8). Record the netmask unless it is a duplicate;
* previously anything but an exact duplicate was dropped (#3588).
*/
if (TreeCheckData(node->prefix, node->prefix->prefix_data,
netmask) == 0) {
CPTData *prefix_data = CPTCreateCPTData(netmask, tree->pool);
CPTAppendToCPTDataList(prefix_data, &prefix->prefix_data);

if(CheckBitmask(netmask, ip_bitmask))
return node;

parent = node->parent;
while (parent != NULL && netmask < (parent->bit + 1)) {
node = parent;
parent = parent->parent;
}

node->count++;
new_node = node;
node->netmasks = apr_palloc(tree->pool, (node->count * sizeof(unsigned char)));

if ((node->count -1) == 0) {
node->netmasks[0] = netmask;
return new_node;
}

node->netmasks[node->count - 1] = netmask;

i = node->count - 2;
while (i >= 0) {
if (netmask < node->netmasks[i]) {
node->netmasks[i + 1] = netmask;
break;
}
if (prefix_data == NULL)

Check failure on line 407 in apache2/msc_tree.c

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SonarQubeCloud / SonarCloud Code Analysis

Refactor this code to not nest more than 3 if|for|do|while|switch statements. 


See more on https://sonarcloud.io/project/issues?id=owasp-modsecurity_ModSecurity&issues=AaE1RdL3VPUT6YxDaeVx&open=AaE1RdL3VPUT6YxDaeVx&pullRequest=3671
return NULL;
CPTAppendToCPTDataList(prefix_data, &node->prefix->prefix_data);

node->netmasks[i + 1] = node->netmasks[i];
node->netmasks[i] = netmask;
i--;
if (CheckBitmask(netmask, ip_bitmask) == 0) {

Check failure on line 411 in apache2/msc_tree.c

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SonarQubeCloud / SonarCloud Code Analysis

Refactor this code to not nest more than 3 if|for|do|while|switch statements. 


See more on https://sonarcloud.io/project/issues?id=owasp-modsecurity_ModSecurity&issues=AaE1RdL3VPUT6YxDaeVy&open=AaE1RdL3VPUT6YxDaeVy&pullRequest=3671
InsertNetmask(node, node->parent, node, tree, netmask,
bitlen);
}
}
} else {
Expand Down Expand Up @@ -645,6 +622,10 @@
while(j < netmask_node->count) {
bytes = ip_bitmask / 8;

/* Netmasks are sorted from most to least specific, so masking the
* already masked address again is the same as masking the original.
* Previously only the first netmask was applied (#3588). */
i = 0;
while( i < bytes ) {

mask = -1;
Expand Down
138 changes: 138 additions & 0 deletions tests/regression/misc/60-ipmatch-overlap.t
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Original file line number Diff line number Diff line change
@@ -0,0 +1,138 @@
### @ipMatch with overlapping prefixes on the same key (#3588)

{
type => "misc",
comment => '@ipMatch narrow then wide on the same key, IP in the wide range',
conf => q(
SecRuleEngine On
SecRule ARGS:ip "@ipMatch 10.0.0.0/16,10.0.0.0/8" "id:500588,phase:1,deny,status:403"
),
match_log => {
error => [ qr/Access denied with code 403 \(phase 1\)/, 1 ],
},
match_response => {
status => qr/^403$/,
},
request => new HTTP::Request(
GET => "http://$ENV{SERVER_NAME}:$ENV{SERVER_PORT}/test.txt?ip=10.5.0.1",
),
},
{
type => "misc",
comment => '@ipMatch narrow then wide on the same key, IP in the narrow range',
conf => q(
SecRuleEngine On
SecRule ARGS:ip "@ipMatch 10.0.0.0/16,10.0.0.0/8" "id:500588,phase:1,deny,status:403"
),
match_log => {
error => [ qr/Access denied with code 403 \(phase 1\)/, 1 ],
},
match_response => {
status => qr/^403$/,
},
request => new HTTP::Request(
GET => "http://$ENV{SERVER_NAME}:$ENV{SERVER_PORT}/test.txt?ip=10.0.5.1",
),
},
{
type => "misc",
comment => '@ipMatch wide then narrow on the same key',
conf => q(
SecRuleEngine On
SecRule ARGS:ip "@ipMatch 10.0.0.0/8,10.0.0.0/16" "id:500588,phase:1,deny,status:403"
),
match_log => {
error => [ qr/Access denied with code 403 \(phase 1\)/, 1 ],
},
match_response => {
status => qr/^403$/,
},
request => new HTTP::Request(
GET => "http://$ENV{SERVER_NAME}:$ENV{SERVER_PORT}/test.txt?ip=10.5.0.1",
),
},
{
type => "misc",
comment => '@ipMatch host then network on the same key',
conf => q(
SecRuleEngine On
SecRule ARGS:ip "@ipMatch 172.16.0.0,172.16.0.0/12" "id:500588,phase:1,deny,status:403"
),
match_log => {
error => [ qr/Access denied with code 403 \(phase 1\)/, 1 ],
},
match_response => {
status => qr/^403$/,
},
request => new HTTP::Request(
GET => "http://$ENV{SERVER_NAME}:$ENV{SERVER_PORT}/test.txt?ip=172.20.0.1",
),
},
{
type => "misc",
comment => '@ipMatch duplicate prefixes still match',
conf => q(
SecRuleEngine On
SecRule ARGS:ip "@ipMatch 10.0.0.0/8,127.0.0.1,10.0.0.0/8" "id:500588,phase:1,deny,status:403"
),
match_log => {
error => [ qr/Access denied with code 403 \(phase 1\)/, 1 ],
},
match_response => {
status => qr/^403$/,
},
request => new HTTP::Request(
GET => "http://$ENV{SERVER_NAME}:$ENV{SERVER_PORT}/test.txt?ip=10.5.0.1",
),
},
{
type => "misc",
comment => '@ipMatch address outside every prefix',
conf => q(
SecRuleEngine On
SecRule ARGS:ip "@ipMatch 10.0.0.0/16,10.0.0.0/8,192.168.0.0/16" "id:500588,phase:1,deny,status:403"
),
match_log => {
-error => [ qr/Access denied/, 1 ],
},
match_response => {
status => qr/^200$/,
},
request => new HTTP::Request(
GET => "http://$ENV{SERVER_NAME}:$ENV{SERVER_PORT}/test.txt?ip=11.0.0.1",
),
},
{
type => "misc",
comment => '@ipMatch IPv6 narrow then wide on the same key',
conf => q(
SecRuleEngine On
SecRule ARGS:ip "@ipMatch 2001:db8::/48,2001:db8::/32" "id:500588,phase:1,deny,status:403"
),
match_log => {
error => [ qr/Access denied with code 403 \(phase 1\)/, 1 ],
},
match_response => {
status => qr/^403$/,
},
request => new HTTP::Request(
GET => "http://$ENV{SERVER_NAME}:$ENV{SERVER_PORT}/test.txt?ip=2001:db8:1::1",
),
},
{
type => "misc",
comment => '@ipMatch IPv6 address outside every prefix',
conf => q(
SecRuleEngine On
SecRule ARGS:ip "@ipMatch 2001:db8::/48,2001:db8::/32" "id:500588,phase:1,deny,status:403"
),
match_log => {
-error => [ qr/Access denied/, 1 ],
},
match_response => {
status => qr/^200$/,
},
request => new HTTP::Request(
GET => "http://$ENV{SERVER_NAME}:$ENV{SERVER_PORT}/test.txt?ip=2001:db9::1",
),
},
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