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Provide the SQLITE_MAX_ALLOCATION_SIZE compile-time option for limiting the

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maximum memory allocation size.

FossilOrigin-Name: 584de6a996c78b8e41bdfcd05a8e2a3844664c6b4efedb5883c8b8af388462b5
This commit is contained in:
drh
2022-09-27 16:35:06 +00:00
parent 6319a8003c
commit 5d48e0cdc5
3 changed files with 29 additions and 13 deletions
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28
src/malloc.c
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@@ -270,18 +270,34 @@ static void mallocWithAlarm(int n, void **pp){
*pp = p;
}
/*
** Maximum size of any single memory allocation.
**
** This is not a limit on the total amount of memory used. This is
** a limit on the size parameter to sqlite3_malloc() and sqlite3_realloc().
**
** The upper bound is slightly less than 2GiB: 0x7ffffeff == 2,147,483,391
** This provides a 256-byte safety margin for defense against 32-bit
** signed integer overflow bugs when computing memory allocation sizes.
** Parnoid applications might want to reduce the maximum allocation size
** further for an even larger safety margin. 0x3fffffff or 0x0fffffff
** or even smaller would be reasonable upper bounds on the size of a memory
** allocations for most applications.
*/
#ifndef SQLITE_MAX_ALLOCATION_SIZE
# define SQLITE_MAX_ALLOCATION_SIZE 2147483391
#endif
#if SQLITE_MAX_ALLOCATION_SIZE>2147483391
# error Maximum size for SQLITE_MAX_ALLOCATION_SIZE is 2147483391
#endif
/*
** Allocate memory. This routine is like sqlite3_malloc() except that it
** assumes the memory subsystem has already been initialized.
*/
void *sqlite3Malloc(u64 n){
void *p;
if( n==0 || n>=0x7fffff00 ){
/* A memory allocation of a number of bytes which is near the maximum
** signed integer value might cause an integer overflow inside of the
** xMalloc(). Hence we limit the maximum size to 0x7fffff00, giving
** 255 bytes of overhead. SQLite itself will never use anything near
** this amount. The only way to reach the limit is with sqlite3_malloc() */
if( n==0 || n>SQLITE_MAX_ALLOCATION_SIZE ){
p = 0;
}else if( sqlite3GlobalConfig.bMemstat ){
sqlite3_mutex_enter(mem0.mutex);