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Overview
| Comment: | Fix further buffer overreads triggered by passing corrupt records to the sqlite_dbdata module. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
dbc6a9f7f67256dea96d3245e7bec145 |
| User & Date: | dan 2019-05-09 15:07:46 |
Context
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2019-05-09
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| 15:51 | Fix another corruption related buffer overread in the sqlite_dbdata module. check-in: 5cd728fb user: dan tags: trunk | |
| 15:07 | Fix further buffer overreads triggered by passing corrupt records to the sqlite_dbdata module. check-in: dbc6a9f7 user: dan tags: trunk | |
| 14:15 | Have ".recover" handle cases where the sqlite_master table contains malformed SQL statements. check-in: e736da9c user: dan tags: trunk | |
Changes
Changes to ext/misc/dbdata.c.
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int bHasRowid = 0;
int nPointer = 0;
sqlite3_int64 nPayload = 0;
sqlite3_int64 nHdr = 0;
int iHdr;
int U, X;
int nLocal;
switch( pCsr->aPage[iOff] ){
case 0x02:
nPointer = 4;
break;
case 0x0a:
break;
................................................................................
default:
/* This is not a b-tree page with records on it. Continue. */
pCsr->iCell = pCsr->nCell;
break;
}
if( pCsr->iCell>=pCsr->nCell ){
sqlite3_free(pCsr->aPage);
pCsr->aPage = 0;
if( pCsr->bOnePage ) return SQLITE_OK;
pCsr->iPgno++;
continue;
}
iOff += 8 + nPointer + pCsr->iCell*2;
iOff = get_uint16(&pCsr->aPage[iOff]);
/* For an interior node cell, skip past the child-page number */
iOff += nPointer;
/* Load the "byte of payload including overflow" field */
iOff += dbdataGetVarint(&pCsr->aPage[iOff], &nPayload);
/* If this is a leaf intkey cell, load the rowid */
if( bHasRowid ){
iOff += dbdataGetVarint(&pCsr->aPage[iOff], &pCsr->iIntkey);
}
/* Allocate space for payload */
pCsr->pRec = (u8*)sqlite3_malloc64(nPayload);
if( pCsr->pRec==0 ) return SQLITE_NOMEM;
pCsr->nRec = nPayload;
U = pCsr->nPage;
if( bHasRowid ){
X = U-35;
}else{
X = ((U-12)*64/255)-23;
}
if( nPayload<=X ){
nLocal = nPayload;
}else{
int M, K;
M = ((U-12)*32/255)-23;
K = M+((nPayload-M)%(U-4));
if( K<=X ){
nLocal = K;
}else{
nLocal = M;
}
}
/* Load the nLocal bytes of payload */
memcpy(pCsr->pRec, &pCsr->aPage[iOff], nLocal);
iOff += nLocal;
/* Load content from overflow pages */
if( nPayload>nLocal ){
sqlite3_int64 nRem = nPayload - nLocal;
unsigned int pgnoOvfl = get_uint32(&pCsr->aPage[iOff]);
while( nRem>0 ){
u8 *aOvfl = 0;
int nOvfl = 0;
int nCopy;
rc = dbdataLoadPage(pCsr, pgnoOvfl, &aOvfl, &nOvfl);
assert( rc!=SQLITE_OK || nOvfl==pCsr->nPage );
if( rc!=SQLITE_OK ) return rc;
nCopy = U-4;
if( nCopy>nRem ) nCopy = nRem;
memcpy(&pCsr->pRec[nPayload-nRem], &aOvfl[4], nCopy);
nRem -= nCopy;
pgnoOvfl = get_uint32(aOvfl);
sqlite3_free(aOvfl);
}
}
iHdr = dbdataGetVarint(pCsr->pRec, &nHdr);
pCsr->nHdr = nHdr;
pCsr->pHdrPtr = &pCsr->pRec[iHdr];
pCsr->pPtr = &pCsr->pRec[pCsr->nHdr];
pCsr->iField = (bHasRowid ? -1 : 0);
}else{
pCsr->iField++;
if( pCsr->iField>0 ){
sqlite3_int64 iType;
pCsr->pHdrPtr += dbdataGetVarint(pCsr->pHdrPtr, &iType);
pCsr->pPtr += dbdataValueBytes(iType);
}
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int bHasRowid = 0;
int nPointer = 0;
sqlite3_int64 nPayload = 0;
sqlite3_int64 nHdr = 0;
int iHdr;
int U, X;
int nLocal;
int bNextPage = 0;
switch( pCsr->aPage[iOff] ){
case 0x02:
nPointer = 4;
break;
case 0x0a:
break;
................................................................................
default:
/* This is not a b-tree page with records on it. Continue. */
pCsr->iCell = pCsr->nCell;
break;
}
if( pCsr->iCell>=pCsr->nCell ){
bNextPage = 1;
}else{
iOff += 8 + nPointer + pCsr->iCell*2;
if( iOff>pCsr->nPage ){
bNextPage = 1;
}else{
iOff = get_uint16(&pCsr->aPage[iOff]);
}
/* For an interior node cell, skip past the child-page number */
iOff += nPointer;
/* Load the "byte of payload including overflow" field */
if( bNextPage || iOff>pCsr->nPage ){
bNextPage = 1;
}else{
iOff += dbdataGetVarint(&pCsr->aPage[iOff], &nPayload);
}
/* If this is a leaf intkey cell, load the rowid */
if( bHasRowid && !bNextPage && iOff<pCsr->nPage ){
iOff += dbdataGetVarint(&pCsr->aPage[iOff], &pCsr->iIntkey);
}
/* Figure out how much data to read from the local page */
U = pCsr->nPage;
if( bHasRowid ){
X = U-35;
}else{
X = ((U-12)*64/255)-23;
}
if( nPayload<=X ){
nLocal = nPayload;
}else{
int M, K;
M = ((U-12)*32/255)-23;
K = M+((nPayload-M)%(U-4));
if( K<=X ){
nLocal = K;
}else{
nLocal = M;
}
}
if( bNextPage || nLocal+iOff>pCsr->nPage ){
bNextPage = 1;
}else{
/* Allocate space for payload. And a bit more to catch small buffer
** overruns caused by attempting to read a varint or similar from
** near the end of a corrupt record. */
pCsr->pRec = (u8*)sqlite3_malloc64(nPayload+100);
if( pCsr->pRec==0 ) return SQLITE_NOMEM;
memset(pCsr->pRec, 0, nPayload+100);
pCsr->nRec = nPayload;
/* Load the nLocal bytes of payload */
memcpy(pCsr->pRec, &pCsr->aPage[iOff], nLocal);
iOff += nLocal;
/* Load content from overflow pages */
if( nPayload>nLocal ){
sqlite3_int64 nRem = nPayload - nLocal;
unsigned int pgnoOvfl = get_uint32(&pCsr->aPage[iOff]);
while( nRem>0 ){
u8 *aOvfl = 0;
int nOvfl = 0;
int nCopy;
rc = dbdataLoadPage(pCsr, pgnoOvfl, &aOvfl, &nOvfl);
assert( rc!=SQLITE_OK || nOvfl==pCsr->nPage );
if( rc!=SQLITE_OK ) return rc;
nCopy = U-4;
if( nCopy>nRem ) nCopy = nRem;
memcpy(&pCsr->pRec[nPayload-nRem], &aOvfl[4], nCopy);
nRem -= nCopy;
pgnoOvfl = get_uint32(aOvfl);
sqlite3_free(aOvfl);
}
}
iHdr = dbdataGetVarint(pCsr->pRec, &nHdr);
pCsr->nHdr = nHdr;
pCsr->pHdrPtr = &pCsr->pRec[iHdr];
pCsr->pPtr = &pCsr->pRec[pCsr->nHdr];
pCsr->iField = (bHasRowid ? -1 : 0);
}
}
if( bNextPage ){
sqlite3_free(pCsr->aPage);
pCsr->aPage = 0;
if( pCsr->bOnePage ) return SQLITE_OK;
pCsr->iPgno++;
continue;
}
}else{
pCsr->iField++;
if( pCsr->iField>0 ){
sqlite3_int64 iType;
pCsr->pHdrPtr += dbdataGetVarint(pCsr->pHdrPtr, &iType);
pCsr->pPtr += dbdataValueBytes(iType);
}
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