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inetmib1: Make sure the successor to an item doesn't have an identical key as it, to prevent infinite loops in table enumeration.

This commit is contained in:
Juan Lang 2009-05-13 12:36:42 -07:00 committed by Alexandre Julliard
parent 5d63179404
commit 9b65338ef9
1 changed files with 68 additions and 12 deletions
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80
dlls/inetmib1/main.c
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@ -323,7 +323,27 @@ static DWORD oidToIpAddr(AsnObjectIdentifier *oid)
typedef void (*oidToKeyFunc)(AsnObjectIdentifier *oid, void *dst);
typedef int (*compareFunc)(const void *key, const void *value);
static UINT findValueInTable(AsnObjectIdentifier *oid,
/* Finds the first value in the table that matches key. Returns its 1-based
* index if found, or 0 if not found.
*/
static UINT findValueInTable(const void *key,
struct GenericTable *table, size_t tableEntrySize, compareFunc compare)
{
UINT index = 0;
void *value;
value = bsearch(key, table->entries, table->numEntries, tableEntrySize,
compare);
if (value)
index = ((BYTE *)value - (BYTE *)table->entries) / tableEntrySize + 1;
return index;
}
/* Finds the first value in the table that matches oid, using makeKey to
* convert the oid to a key for comparison. Returns the value's 1-based
* index if found, or 0 if not found.
*/
static UINT findOidInTable(AsnObjectIdentifier *oid,
struct GenericTable *table, size_t tableEntrySize, oidToKeyFunc makeKey,
compareFunc compare)
{
@ -332,14 +352,50 @@ static UINT findValueInTable(AsnObjectIdentifier *oid,
if (key)
{
void *value;
makeKey(oid, key);
value = bsearch(key, table->entries, table->numEntries, tableEntrySize,
compare);
if (value)
index = ((BYTE *)value - (BYTE *)table->entries) / tableEntrySize
+ 1;
index = findValueInTable(key, table, tableEntrySize, compare);
HeapFree(GetProcessHeap(), 0, key);
}
return index;
}
/* Finds the first successor to the value in the table that does matches oid,
* using makeKey to convert the oid to a key for comparison. A successor is
* a value that does not match oid, so if multiple entries match an oid, only
* the first will ever be returned using this method.
* Returns the successor's 1-based index if found, or 0 if not found.
*/
static UINT findNextOidInTable(AsnObjectIdentifier *oid,
struct GenericTable *table, size_t tableEntrySize, oidToKeyFunc makeKey,
compareFunc compare)
{
UINT index = 0;
void *key = HeapAlloc(GetProcessHeap(), 0, tableEntrySize);
if (key)
{
makeKey(oid, key);
index = findValueInTable(key, table, tableEntrySize, compare);
if (index == 0)
{
/* Not found in table. If it's less than the first entry, return
* the first index. Otherwise just return 0 and let the caller
* handle finding the successor.
*/
if (compare(key, table->entries) < 0)
index = 1;
}
else
{
/* Skip any entries that match the same key. This enumeration will
* be incomplete, but it's what Windows appears to do if there are
* multiple entries with the same index in a table, and it avoids
* an infinite loop.
*/
for (++index; index <= table->numEntries && compare(key,
&table->entries[tableEntrySize * index]) == 0; ++index)
;
}
HeapFree(GetProcessHeap(), 0, key);
}
return index;
@ -403,9 +459,9 @@ static AsnInteger32 getItemAndInstanceFromTable(AsnObjectIdentifier *oid,
AsnObjectIdentifier ipOid = { instanceLen,
oid->ids + base->idLength + 1 };
*instance = findValueInTable(&ipOid, table, tableEntrySize,
makeKey, compare) + 1;
if (*instance > table->numEntries)
*instance = findNextOidInTable(&ipOid, table, tableEntrySize,
makeKey, compare);
if (!*instance || *instance > table->numEntries)
ret = SNMP_ERRORSTATUS_NOSUCHNAME;
}
}
@ -424,7 +480,7 @@ static AsnInteger32 getItemAndInstanceFromTable(AsnObjectIdentifier *oid,
AsnObjectIdentifier ipOid = { instanceLen,
oid->ids + base->idLength + 1 };
*instance = findValueInTable(&ipOid, table, tableEntrySize,
*instance = findOidInTable(&ipOid, table, tableEntrySize,
makeKey, compare);
if (!*instance)
ret = SNMP_ERRORSTATUS_NOSUCHNAME;