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Overview
| Comment: | Avoid doing comparisons with pointers that might have been previously been passed to realloc() and/or free(). |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
f20396adb2cff12a17a3fc90b36241ae |
| User & Date: | drh 2015-12-08 16:08:10 |
Context
|
2015-12-08
| ||
| 16:58 | Changes to avoid undefined behavior in memset() and memcpy() and in the comparisons of pointers from different allocations. All problems are found by analysis tools - none have been seen in the wild. check-in: 901d0b8f user: drh tags: trunk | |
| 16:08 | Avoid doing comparisons with pointers that might have been previously been passed to realloc() and/or free(). check-in: f20396ad user: drh tags: trunk | |
| 04:18 | Add a test case of the form "WHERE a<2 OR a<3" using PRAGMA count_changes. This test case was failing before the 3.9.0 release. check-in: 177862c1 user: drh tags: trunk | |
Changes
Changes to src/printf.c.
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return 0;
}
if( p->mxAlloc==0 ){
N = p->nAlloc - p->nChar - 1;
setStrAccumError(p, STRACCUM_TOOBIG);
return N;
}else{
char *zOld = (p->zText==p->zBase ? 0 : p->zText);
i64 szNew = p->nChar;
szNew += N + 1;
if( szNew+p->nChar<=p->mxAlloc ){
/* Force exponential buffer size growth as long as it does not overflow,
** to avoid having to call this routine too often */
szNew += p->nChar;
}
if( szNew > p->mxAlloc ){
................................................................................
if( p->db ){
zNew = sqlite3DbRealloc(p->db, zOld, p->nAlloc);
}else{
zNew = sqlite3_realloc64(zOld, p->nAlloc);
}
if( zNew ){
assert( p->zText!=0 || p->nChar==0 );
if( p->zText==p->zBase && p->nChar>0 ) memcpy(zNew, p->zText, p->nChar);
p->zText = zNew;
p->nAlloc = sqlite3DbMallocSize(p->db, zNew);
}else{
sqlite3StrAccumReset(p);
setStrAccumError(p, STRACCUM_NOMEM);
return 0;
}
}
return N;
................................................................................
** Append N copies of character c to the given string buffer.
*/
void sqlite3AppendChar(StrAccum *p, int N, char c){
testcase( p->nChar + (i64)N > 0x7fffffff );
if( p->nChar+(i64)N >= p->nAlloc && (N = sqlite3StrAccumEnlarge(p, N))<=0 ){
return;
}
while( (N--)>0 ) p->zText[p->nChar++] = c;
}
/*
** The StrAccum "p" is not large enough to accept N new bytes of z[].
** So enlarge if first, then do the append.
**
................................................................................
*/
static void SQLITE_NOINLINE enlargeAndAppend(StrAccum *p, const char *z, int N){
N = sqlite3StrAccumEnlarge(p, N);
if( N>0 ){
memcpy(&p->zText[p->nChar], z, N);
p->nChar += N;
}
}
/*
** Append N bytes of text from z to the StrAccum object. Increase the
** size of the memory allocation for StrAccum if necessary.
*/
void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
................................................................................
/*
** Finish off a string by making sure it is zero-terminated.
** Return a pointer to the resulting string. Return a NULL
** pointer if any kind of error was encountered.
*/
char *sqlite3StrAccumFinish(StrAccum *p){
if( p->zText ){
p->zText[p->nChar] = 0;
if( p->mxAlloc>0 && p->zText==p->zBase ){
p->zText = sqlite3DbMallocRaw(p->db, p->nChar+1 );
if( p->zText ){
memcpy(p->zText, p->zBase, p->nChar+1);
}else{
setStrAccumError(p, STRACCUM_NOMEM);
}
}
}
return p->zText;
}
/*
** Reset an StrAccum string. Reclaim all malloced memory.
*/
void sqlite3StrAccumReset(StrAccum *p){
if( p->zText!=p->zBase ){
sqlite3DbFree(p->db, p->zText);
}
p->zText = 0;
}
/*
** Initialize a string accumulator.
**
................................................................................
void sqlite3StrAccumInit(StrAccum *p, sqlite3 *db, char *zBase, int n, int mx){
p->zText = p->zBase = zBase;
p->db = db;
p->nChar = 0;
p->nAlloc = n;
p->mxAlloc = mx;
p->accError = 0;
}
/*
** Print into memory obtained from sqliteMalloc(). Use the internal
** %-conversion extensions.
*/
char *sqlite3VMPrintf(sqlite3 *db, const char *zFormat, va_list ap){
|
| > | > > > > | > | > > > |
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return 0;
}
if( p->mxAlloc==0 ){
N = p->nAlloc - p->nChar - 1;
setStrAccumError(p, STRACCUM_TOOBIG);
return N;
}else{
char *zOld = p->bMalloced ? p->zText : 0;
i64 szNew = p->nChar;
assert( (p->zText==0 || p->zText==p->zBase)==(p->bMalloced==0) );
szNew += N + 1;
if( szNew+p->nChar<=p->mxAlloc ){
/* Force exponential buffer size growth as long as it does not overflow,
** to avoid having to call this routine too often */
szNew += p->nChar;
}
if( szNew > p->mxAlloc ){
................................................................................
if( p->db ){
zNew = sqlite3DbRealloc(p->db, zOld, p->nAlloc);
}else{
zNew = sqlite3_realloc64(zOld, p->nAlloc);
}
if( zNew ){
assert( p->zText!=0 || p->nChar==0 );
if( !p->bMalloced && p->nChar>0 ) memcpy(zNew, p->zText, p->nChar);
p->zText = zNew;
p->nAlloc = sqlite3DbMallocSize(p->db, zNew);
p->bMalloced = 1;
}else{
sqlite3StrAccumReset(p);
setStrAccumError(p, STRACCUM_NOMEM);
return 0;
}
}
return N;
................................................................................
** Append N copies of character c to the given string buffer.
*/
void sqlite3AppendChar(StrAccum *p, int N, char c){
testcase( p->nChar + (i64)N > 0x7fffffff );
if( p->nChar+(i64)N >= p->nAlloc && (N = sqlite3StrAccumEnlarge(p, N))<=0 ){
return;
}
assert( (p->zText==p->zBase)==(p->bMalloced==0) );
while( (N--)>0 ) p->zText[p->nChar++] = c;
}
/*
** The StrAccum "p" is not large enough to accept N new bytes of z[].
** So enlarge if first, then do the append.
**
................................................................................
*/
static void SQLITE_NOINLINE enlargeAndAppend(StrAccum *p, const char *z, int N){
N = sqlite3StrAccumEnlarge(p, N);
if( N>0 ){
memcpy(&p->zText[p->nChar], z, N);
p->nChar += N;
}
assert( (p->zText==0 || p->zText==p->zBase)==(p->bMalloced==0) );
}
/*
** Append N bytes of text from z to the StrAccum object. Increase the
** size of the memory allocation for StrAccum if necessary.
*/
void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
................................................................................
/*
** Finish off a string by making sure it is zero-terminated.
** Return a pointer to the resulting string. Return a NULL
** pointer if any kind of error was encountered.
*/
char *sqlite3StrAccumFinish(StrAccum *p){
if( p->zText ){
assert( (p->zText==p->zBase)==(p->bMalloced==0) );
p->zText[p->nChar] = 0;
if( p->mxAlloc>0 && p->bMalloced==0 ){
p->zText = sqlite3DbMallocRaw(p->db, p->nChar+1 );
if( p->zText ){
memcpy(p->zText, p->zBase, p->nChar+1);
p->bMalloced = 1;
}else{
setStrAccumError(p, STRACCUM_NOMEM);
}
}
}
return p->zText;
}
/*
** Reset an StrAccum string. Reclaim all malloced memory.
*/
void sqlite3StrAccumReset(StrAccum *p){
assert( (p->zText==0 || p->zText==p->zBase)==(p->bMalloced==0) );
if( p->bMalloced ){
sqlite3DbFree(p->db, p->zText);
p->bMalloced = 0;
}
p->zText = 0;
}
/*
** Initialize a string accumulator.
**
................................................................................
void sqlite3StrAccumInit(StrAccum *p, sqlite3 *db, char *zBase, int n, int mx){
p->zText = p->zBase = zBase;
p->db = db;
p->nChar = 0;
p->nAlloc = n;
p->mxAlloc = mx;
p->accError = 0;
p->bMalloced = 0;
}
/*
** Print into memory obtained from sqliteMalloc(). Use the internal
** %-conversion extensions.
*/
char *sqlite3VMPrintf(sqlite3 *db, const char *zFormat, va_list ap){
|
Changes to src/sqliteInt.h.
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sqlite3 *db; /* Optional database for lookaside. Can be NULL */ char *zBase; /* A base allocation. Not from malloc. */ char *zText; /* The string collected so far */ int nChar; /* Length of the string so far */ int nAlloc; /* Amount of space allocated in zText */ int mxAlloc; /* Maximum allowed allocation. 0 for no malloc usage */ u8 accError; /* STRACCUM_NOMEM or STRACCUM_TOOBIG */ }; #define STRACCUM_NOMEM 1 #define STRACCUM_TOOBIG 2 /* ** A pointer to this structure is used to communicate information ** from sqlite3Init and OP_ParseSchema into the sqlite3InitCallback. |
> |
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sqlite3 *db; /* Optional database for lookaside. Can be NULL */
char *zBase; /* A base allocation. Not from malloc. */
char *zText; /* The string collected so far */
int nChar; /* Length of the string so far */
int nAlloc; /* Amount of space allocated in zText */
int mxAlloc; /* Maximum allowed allocation. 0 for no malloc usage */
u8 accError; /* STRACCUM_NOMEM or STRACCUM_TOOBIG */
u8 bMalloced; /* zText points to allocated space */
};
#define STRACCUM_NOMEM 1
#define STRACCUM_TOOBIG 2
/*
** A pointer to this structure is used to communicate information
** from sqlite3Init and OP_ParseSchema into the sqlite3InitCallback.
|