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Fix Windows stack-overflow recursion between the log sink and the memory-security allocator #602

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Fix Windows stack-overflow recursion between the log sink and the memory-security allocator #602

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34 changes: 33 additions & 1 deletion src/sqlcipher.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2577,12 +2577,41 @@ static char *sqlcipher_get_log_sources_str(unsigned int source) {
#define FILETIME_1970 116444736000000000ull /* seconds between 1/1/1601 and 1/1/1970 */
#define HECTONANOSEC_PER_SEC 10000000ull
#define MAX_LOG_LEN 8192

#ifdef _WIN32
#ifdef _MSC_VER
#define SQLCIPHER_TLS __declspec(thread)
#else
#define SQLCIPHER_TLS __thread
#endif
/* Guards against unbounded same-thread reentrancy through the console log
sink. On Windows, sqlcipher_fprintf converts messages to UTF-16 by
allocating through sqlite3_vmprintf and sqlite3_malloc. When
cipher_memory_security is enabled those allocations go through the locked
allocator, whose VirtualLock call can fail once the process working-set
quota is exhausted (commonly observed as "VirtualLock() returned 0
LastError=1453"). That failure is itself logged, and writing the warning
allocates again, fails again, and logs again, recursing until the stack
overflows. Messages emitted while this thread is already inside
sqlcipher_log are therefore dropped. */
static SQLCIPHER_TLS int sqlcipher_log_active = 0;
#endif

void sqlcipher_log(unsigned int level, unsigned int source, const char *message, ...) {
va_list params;
va_start(params, message);
char formatted[MAX_LOG_LEN];
size_t len = 0;

#ifdef _WIN32
if(sqlcipher_log_active) {
/* re-entered from within the log sink's own allocation path */
return;
}
sqlcipher_log_active = 1;
#endif

va_start(params, message);

#ifdef CODEC_DEBUG
#if defined(SQLCIPHER_OMIT_LOG_DEVICE) || (!defined(__ANDROID__) && !defined(__APPLE__))
sqlite3_vsnprintf(MAX_LOG_LEN, formatted, message, params);
Expand Down Expand Up @@ -2653,6 +2682,9 @@ void sqlcipher_log(unsigned int level, unsigned int source, const char *message,

end:
va_end(params);
#ifdef _WIN32
sqlcipher_log_active = 0;
#endif
}
#endif

Expand Down