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Overview
| Comment: | Prevent the printf formatter from doing large memory allocations - larger than either the size of the static buffer for interfaces like sqlite3_snprintf(), or larger than SQLITE_LIMIT_LENGTH for interfaces that are associated with a database connection. This helps to prevent DOS attacks on products that let hostile sources inject arbitrary SQL. It also helps fuzzers run faster and more effectively. |
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| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
179e5d46054e5c86f53a79b7a0823d9a |
| User & Date: | drh 2019-02-01 20:29:04.040 |
Context
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2019-02-01
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| 21:08 | Slight adjustment to the printf formatter large memory allocation detector so that it does not overestimate the amount of space needed for oversize %d conversions. (check-in: 1aee70d6de user: drh tags: trunk) | |
| 20:29 | Prevent the printf formatter from doing large memory allocations - larger than either the size of the static buffer for interfaces like sqlite3_snprintf(), or larger than SQLITE_LIMIT_LENGTH for interfaces that are associated with a database connection. This helps to prevent DOS attacks on products that let hostile sources inject arbitrary SQL. It also helps fuzzers run faster and more effectively. (check-in: 179e5d4605 user: drh tags: trunk) | |
| 18:46 | Performance improvement in the parsing of options to %-formats in the printf implementation. (check-in: 40d8f8ae87 user: drh tags: trunk) | |
Changes
Changes to src/printf.c.
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return sqlite3_value_double(p->apArg[p->nUsed++]);
}
static char *getTextArg(PrintfArguments *p){
if( p->nArg<=p->nUsed ) return 0;
return (char*)sqlite3_value_text(p->apArg[p->nUsed++]);
}
/*
** Allocate memory for a temporary buffer needed for printf rendering.
**
** If the requested size of the temp buffer is larger than the size
** of the output buffer in pAccum, then cause an SQLITE_TOOBIG error.
** Do the size check before the memory allocation to prevent rogue
** SQL from requesting large allocations using the precision or width
** field of the printf() function.
*/
static char *printfTempBuf(sqlite3_str *pAccum, sqlite3_int64 n){
char *z;
if( n>pAccum->nAlloc && n>pAccum->mxAlloc ){
setStrAccumError(pAccum, SQLITE_TOOBIG);
return 0;
}
z = sqlite3DbMallocRaw(pAccum->db, n);
if( z==0 ){
setStrAccumError(pAccum, SQLITE_NOMEM);
}
return z;
}
/*
** On machines with a small stack size, you can redefine the
** SQLITE_PRINT_BUF_SIZE to be something smaller, if desired.
*/
#ifndef SQLITE_PRINT_BUF_SIZE
# define SQLITE_PRINT_BUF_SIZE 70
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precision = width-(prefix!=0);
}
if( precision<etBUFSIZE-10-etBUFSIZE/3 ){
nOut = etBUFSIZE;
zOut = buf;
}else{
u64 n = (u64)precision + 10 + precision/3;
|
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flag_rtz = flag_altform2;
}
if( xtype==etEXP ){
e2 = 0;
}else{
e2 = exp;
}
{
i64 szBufNeeded; /* Size of a temporary buffer needed */
|
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if( flag_altform2 && (ch&0xc0)==0xc0 ){
while( (escarg[i+1]&0xc0)==0x80 ){ i++; }
}
}
needQuote = !isnull && xtype==etSQLESCAPE2;
n += i + 3;
if( n>etBUFSIZE ){
|
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