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List: licq-devel
Subject: [Licq-devel] [PATCH] reliability patch 0
From: Tim van Erven <tripudium () chello ! nl>
Date: 2002-06-11 13:03:34
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Hi,
I'm going over various bits of the licq source, trying to improve its
reliability. My main focus is to remove potential memorycorruption
issues (e.g. bufferoverflows). Here's a first patch, expect more.
--
Tim van Erven <tripudium@chello.nl>
OpenPGP Key ID: 712CB811 Fingerprint: F6C9 61EE 242C C012 36D5
BBF8 6310 D557 712C B811
["licq-reliability_0.patch" (text/plain)]
diff -u -ur -X dontdiff licq-orig/include/licq_file.h licq/include/licq_file.h
--- licq-orig/include/licq_file.h Mon Jun 10 20:06:12 2002
+++ licq/include/licq_file.h Tue Jun 11 00:21:04 2002
@@ -78,10 +78,11 @@
m_bChanged;
// Functions
- char *ReadLine(char *_szBuffer);
- char *GetSectionFromLine(char *_szLine, char *_szBuffer);
- char *GetKeyFromLine(char *_szLine, char *_szBuffer);
- char *GetDataFromLine(char *_szLine, char *_szBuffer, bool bTrim = true);
+ char *ReadLine(char *_szDest, int nDestSize);
+ char *GetSectionFromLine(char *_szBuffer, const char *_szLine);
+ char *GetKeyFromLine(char *_szBuffer, const char *_szLine);
+ char *GetDataFromLine(char *_szBuffer, const char *_szLine,
+ bool bTrim = true);
void Warn(int nError, const char *_sz = NULL);
void InsertStr(const char *_szNewStr, int _nCutStart, int _nCutEnd);
diff -u -ur -X dontdiff licq-orig/src/file.cpp licq/src/file.cpp
--- licq-orig/src/file.cpp Mon Jun 10 20:06:12 2002
+++ licq/src/file.cpp Tue Jun 11 01:36:04 2002
@@ -27,6 +27,11 @@
*---------------------------------------------------------------------------*/
void Trim(char *_sz)
{
+ if (_sz == NULL)
+ {
+ gLog.Warn("%sInternal Error: Trim(): _sz == NULL.\n", L_WARNxSTR);
+ return;
+ }
char* b, *e;
b = _sz; while(*b && isspace(*b)) b++;
@@ -88,26 +93,37 @@
/*-----RemoveNewLines----------------------------------------------------------
* Replaces all occurences of '\n' in a string by "\n"
*---------------------------------------------------------------------------*/
-void RemoveNewLines(char *_szDest, const char *_szSource)
+void RemoveNewLines(char *_szDest, int _nDestSize, const char *_szSource)
{
if (_szSource == NULL || _szDest == NULL)
{
- gLog.Warn("%sInternal Error: RemoveNewLines(): _szDest == NULL or _szSource == \
NULL.\n", L_WARNxSTR); + gLog.Warn("%sInternal Error: RemoveNewLines(): _szDest == \
NULL or " + "_szSource == NULL.\n", L_WARNxSTR);
return;
}
int i = 0, j = 0;
while (_szSource[i] != '\0')
{
+ if (j >= _nDestSize) break;
if (_szSource[i] == '\n')
{
_szDest[j++] = '\\';
+ if (j >= _nDestSize) break;
_szDest[j++] = 'n';
}
else
_szDest[j++] = _szSource[i];
i++;
}
- _szDest[j] = '\0';
+ if (j < _nDestSize)
+ _szDest[j] = '\0';
+ else
+ {
+ if (_nDestSize > 0) _szDest[_nDestSize - 1] = '\0';
+ gLog.Warn("%sInternal Error: RemoveNewLines(): Destination buffer too "
+ "small.\n", L_WARNxSTR);
+ return;
+ }
}
@@ -188,6 +204,7 @@
if (m_nBufSize < 0)
{
free(m_szBuffer);
+ m_szBuffer = NULL;
m_nError = errno;
Warn(INI_ExIOREAD);
return false;
@@ -217,11 +234,18 @@
//-----FlushFile---------------------------------------------------------------
+/* FlushFile is susceptible to a symlink attack. If [m_szFilename].new
+ * already exists, it will be truncated and removed. */
bool CIniFile::FlushFile()
{
- // Write files atomically to avoid config trashing
+ // Write files atomically to avoid config trashing.
char tempname[MAX_FILENAME_LEN];
+ if (strlen(m_szFilename) + 4 >= MAX_FILENAME_LEN)
+ {
+ Warn(INI_ExIOWRITE);
+ return false;
+ }
strcpy(tempname, m_szFilename);
strcat(tempname, ".new");
@@ -351,7 +375,7 @@
* ending at the first new line. Returns NULL if we are already at the EOF
* or EOS. Will not return lines beginning with a # (comments)
*---------------------------------------------------------------------------*/
-char *CIniFile::ReadLine(char *_szBuffer)
+char *CIniFile::ReadLine(char *_szDest, int _nDestSize)
{
int i = 0;
if (m_nBufPos >= m_nBufSize)
@@ -367,23 +391,23 @@
}
// the buffer will always end in a newline, so we can just check for it
- while (m_szBuffer[m_nBufPos] != '\n')
- _szBuffer[i++] = m_szBuffer[m_nBufPos++];
+ while (m_szBuffer[m_nBufPos] != '\n' && i < _nDestSize - 1)
+ _szDest[i++] = m_szBuffer[m_nBufPos++];
// Increase the buffer pos to get past the newline
m_nBufPos++;
// Replace the newline with a null
- _szBuffer[i] = '\0';
+ _szDest[i] = '\0';
- return(_szBuffer);
+ return(_szDest);
}
/*-----GetSectionFromLine------------------------------------------------------
* Extracts the section name from a given line of text. Returns an empty
- * string if the line does not contain a section, or NULL is the given line
+ * string if the line does not contain a section, or NULL if the given line
* is NULL or there is an open ([) with no closing (]).
*---------------------------------------------------------------------------*/
-char *CIniFile::GetSectionFromLine(char *_szLine, char *_szBuffer)
+char *CIniFile::GetSectionFromLine(char *_szBuffer, const char *_szLine)
{
//static char s_szSectionName[MAX_SECTIONxNAME_LEN];
@@ -396,7 +420,8 @@
{
int i = 1;
int j = 0;
- while (_szLine[i] != ']' && _szLine[i] != '\0')
+ while (_szLine[i] != ']' && _szLine[i] != '\0' &&
+ j < MAX_SECTIONxNAME_LEN)
_szBuffer[j++] = _szLine[i++];
if (_szLine[i] == '\0')
{
@@ -415,7 +440,7 @@
* Extracts a key name from a given line of text. Returns NULL if the given
* line is NULL or if there is no = on a non-empty the line.
*---------------------------------------------------------------------------*/
-char *CIniFile::GetKeyFromLine(char *_szLine, char *_szBuffer)
+char *CIniFile::GetKeyFromLine(char *_szBuffer, const char *_szLine)
{
if (_szLine == NULL) return NULL;
@@ -448,12 +473,19 @@
* Extracts the data from a given line, ie the characters after the '='.
* Returns NULL if the given line is NULL or there is no '=' on the line.
*---------------------------------------------------------------------------*/
-char *CIniFile::GetDataFromLine(char *_szLine, char *_szBuffer, bool bTrim)
+char *CIniFile::GetDataFromLine(char *_szBuffer, const char *_szLine,
+ bool bTrim)
{
//static char s_szData[MAX_LINE_LEN];
char *szPostEquals;
char szData[MAX_LINE_LEN];
+ if (_szLine == NULL)
+ {
+ Warn(INI_ExFORMAT, _szLine);
+ return NULL;
+ }
+
// Skip the line if it is blank or a comment
if (_szLine[0] == '\n'|| _szLine[0] == '#')
{
@@ -461,15 +493,14 @@
}
else
{
- /* Check for a NULL string, and if not, then get the position of the
- * first '=' */
- if (_szLine == NULL || (szPostEquals = strchr(_szLine, '=')) == NULL)
+ if ((szPostEquals = strchr(_szLine, '=')) == NULL)
{
Warn(INI_ExFORMAT, _szLine);
return NULL;
}
- strcpy(szData, szPostEquals + 1);
+ strncpy(szData, szPostEquals + 1, MAX_LINE_LEN);
+ szData[MAX_LINE_LEN - 1] = '\0';
if (bTrim) Trim(szData);
AddNewLines(_szBuffer, szData);
}
@@ -497,7 +528,8 @@
char *sz, szLineBuffer[MAX_LINE_LEN], szSectionBuffer[MAX_SECTIONxNAME_LEN];
do
{
- sz = GetSectionFromLine(ReadLine(szLineBuffer), szSectionBuffer);
+ sz = GetSectionFromLine(szSectionBuffer,
+ ReadLine(szLineBuffer, MAX_LINE_LEN));
if (sz == NULL)
{
if (GetFlag(INI_FxALLOWxCREATE))
@@ -526,7 +558,7 @@
do
{
nTempPos = m_nBufPos;
- sz = ReadLine(szLineBuffer);
+ sz = ReadLine(szLineBuffer, MAX_LINE_LEN);
}
while(sz != NULL && sz[0] != '[');
@@ -546,7 +578,7 @@
* Finds a key and sets the data. Returns false if the key does not exist.
*---------------------------------------------------------------------------*/
bool CIniFile::ReadStr(const char *szKey, char *szData,
- const char *szDefault, bool bTrim)
+ const char *szDefault, bool bTrim)
{
char *sz, *szLine, szLineBuffer[MAX_LINE_LEN], szKeyBuffer[MAX_KEYxNAME_LEN];
@@ -554,8 +586,8 @@
do
{
- szLine = ReadLine(szLineBuffer);
- sz = GetKeyFromLine(szLine, szKeyBuffer);
+ szLine = ReadLine(szLineBuffer, MAX_LINE_LEN);
+ sz = GetKeyFromLine(szKeyBuffer, szLine);
if (sz == NULL)
{
if (szLine == NULL) Warn(INI_ExNOKEY, szKey);
@@ -565,7 +597,7 @@
}
while (strcmp(sz, szKey) != 0);
- if ((sz = GetDataFromLine(szLine, szData, bTrim)) == NULL)
+ if ((sz = GetDataFromLine(szData, szLine, bTrim)) == NULL)
{
if (szDefault != NULL) strcpy(szData, szDefault);
return (false);
@@ -578,7 +610,8 @@
* Finds a key and sets the numeric data. Returns false if the key does not
* exist.
*---------------------------------------------------------------------------*/
-bool CIniFile::ReadNum(const char *_szKey, unsigned long &data, const unsigned long \
_nDefault) +bool CIniFile::ReadNum(const char *_szKey, unsigned long &data,
+ const unsigned long _nDefault)
{
char szData[MAX_LINE_LEN];
if (!ReadStr(_szKey, szData, NULL))
@@ -587,11 +620,12 @@
return (false);
}
- data = (unsigned long)atoi(szData);
+ data = (unsigned long)atol(szData);
return(true);
}
-bool CIniFile::ReadNum(const char *_szKey, unsigned short &data, const unsigned \
short _nDefault) +bool CIniFile::ReadNum(const char *_szKey, unsigned short &data,
+ const unsigned short _nDefault)
{
char szData[MAX_LINE_LEN];
if (!ReadStr(_szKey, szData, NULL))
@@ -618,7 +652,8 @@
return(true);
}
-bool CIniFile::ReadNum(const char *_szKey, signed short &data, const signed short \
_nDefault) +bool CIniFile::ReadNum(const char *_szKey, signed short &data,
+ const signed short _nDefault)
{
char szData[MAX_LINE_LEN];
if (!ReadStr(_szKey, szData, NULL))
@@ -660,9 +695,10 @@
char *szNewBuffer = (char *)malloc(nNewBufSize + 1);
memcpy(szNewBuffer, m_szBuffer, _nCutStart);
memcpy(szNewBuffer + _nCutStart, _szNewStr, nNewStrLen);
- memcpy(szNewBuffer + _nCutStart + nNewStrLen, m_szBuffer + _nCutEnd, m_nBufSize - \
_nCutEnd + 1); + memcpy(szNewBuffer + _nCutStart + nNewStrLen, m_szBuffer + \
_nCutEnd, + m_nBufSize - _nCutEnd + 1);
- free (m_szBuffer);
+ free(m_szBuffer);
m_szBuffer = szNewBuffer;
m_nBufSize = nNewBufSize;
m_bChanged = true;
@@ -714,21 +750,23 @@
do
{
nCutStart = m_nBufPos;
- szLine = ReadLine(szLineBuffer);
- sz = GetKeyFromLine(szLine, szKeyBuffer);
+ szLine = ReadLine(szLineBuffer, MAX_LINE_LEN);
+ sz = GetKeyFromLine(szKeyBuffer, szLine);
}
while (sz != NULL && strcmp(sz, _szKey) != 0);
int nCutEnd = m_nBufPos;
char szNewLine[MAX_LINE_LEN], szDataNoNL[MAX_LINE_LEN];
if (_szData != NULL)
- RemoveNewLines(szDataNoNL, _szData);
+ RemoveNewLines(szDataNoNL, MAX_LINE_LEN, _szData);
else
{
- gLog.Warn("%sInternal Error: CIniFile::WriteStr(%s, NULL).\n", L_WARNxSTR, \
_szKey); + gLog.Warn("%sInternal Error: CIniFile::WriteStr(%s, NULL).\n",
+ L_WARNxSTR, _szKey);
strcpy(szDataNoNL, "");
}
snprintf(szNewLine, MAX_LINE_LEN, "%s = %s\n", _szKey, szDataNoNL);
+ szNewLine[MAX_LINE_LEN - 1] = '\0';
// Check if we are appending a new key to the section
if (sz == NULL) m_nSectionEnd += strlen(szNewLine);
@@ -742,28 +780,32 @@
bool CIniFile::WriteNum(const char *_szKey, const unsigned short _nData)
{
char szN[32];
- sprintf(szN, "%u", _nData);
+ snprintf(szN, 32, "%u", _nData);
+ szN[31] = '\0';
return(WriteStr(_szKey, szN));
}
bool CIniFile::WriteNum(const char *_szKey, const unsigned long _nData)
{
char szN[32];
- sprintf(szN, "%lu", _nData);
+ snprintf(szN, 32, "%lu", _nData);
+ szN[31] = '\0';
return(WriteStr(_szKey, szN));
}
bool CIniFile::WriteNum(const char *_szKey, const signed short _nData)
{
char szN[32];
- sprintf(szN, "%d", _nData);
+ snprintf(szN, 32, "%d", _nData);
+ szN[31] = '\0';
return(WriteStr(_szKey, szN));
}
bool CIniFile::WriteNum(const char *_szKey, const char _nData)
{
char szN[32];
- sprintf(szN, "%d", _nData);
+ snprintf(szN, 32, "%d", _nData);
+ szN[31] = '\0';
return(WriteStr(_szKey, szN));
}
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