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Revert "Fixed double-free during multi-threaded hidapi access" 

This reverts commit 2b386b6c80.

This isn't the right approach. Even if the string itself isn't double-freed, it can be returned to the application and then freed while the application is trying to use it. This really needs to be in thread-local storage to be completely safe.

In SDL we already have a global thread-local error string, so I'm going to make an SDL-specific change to handle the error strings safely.
main
Sam Lantinga 2023-05-26 23:16:45 -07:00
parent 1c9aae9a29
commit d51f84a2e1
4 changed files with 8 additions and 45 deletions
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1
src/hidapi/SDL_hidapi.c
View File

@ -529,7 +529,6 @@ static void HIDAPI_ShutdownDiscovery(void)
/* Platform HIDAPI Implementation */ /* Platform HIDAPI Implementation */
#define HIDAPI_IGNORE_DEVICE(VID, PID) SDL_HIDAPI_ShouldIgnoreDevice(VID, PID) #define HIDAPI_IGNORE_DEVICE(VID, PID) SDL_HIDAPI_ShouldIgnoreDevice(VID, PID)
#define HIDAPI_ATOMIC_SET_POINTER(a, v) SDL_AtomicSetPtr((void **)a, v)
struct PLATFORM_hid_device_; struct PLATFORM_hid_device_;
typedef struct PLATFORM_hid_device_ PLATFORM_hid_device; typedef struct PLATFORM_hid_device_ PLATFORM_hid_device;

15
src/hidapi/linux/hid.c
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@ -130,19 +130,8 @@ static wchar_t *utf8_to_wchar_t(const char *utf8)
* Use register_error_str(NULL) to free the error message completely. */ * Use register_error_str(NULL) to free the error message completely. */
static void register_error_str(wchar_t **error_str, const char *msg) static void register_error_str(wchar_t **error_str, const char *msg)
{ {
wchar_t *old_string; free(*error_str);
#ifdef HIDAPI_ATOMIC_SET_POINTER *error_str = utf8_to_wchar_t(msg);
old_string = HIDAPI_ATOMIC_SET_POINTER(error_str, NULL);
#else
old_string = *error_str; *error_str = NULL;
#endif
if (old_string) {
free(old_string);
}
if (msg) {
*error_str = utf8_to_wchar_t(msg);
}
} }
/* Semilar to register_error_str, but allows passing a format string with va_list args into this function. */ /* Semilar to register_error_str, but allows passing a format string with va_list args into this function. */

15
src/hidapi/mac/hid.c
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@ -243,19 +243,8 @@ static wchar_t *utf8_to_wchar_t(const char *utf8)
* Use register_error_str(NULL) to free the error message completely. */ * Use register_error_str(NULL) to free the error message completely. */
static void register_error_str(wchar_t **error_str, const char *msg) static void register_error_str(wchar_t **error_str, const char *msg)
{ {
wchar_t *old_string; free(*error_str);
#ifdef HIDAPI_ATOMIC_SET_POINTER *error_str = utf8_to_wchar_t(msg);
old_string = HIDAPI_ATOMIC_SET_POINTER(error_str, NULL);
#else
old_string = *error_str; *error_str = NULL;
#endif
if (old_string) {
free(old_string);
}
if (msg) {
*error_str = utf8_to_wchar_t(msg);
}
} }
/* Similar to register_error_str, but allows passing a format string with va_list args into this function. */ /* Similar to register_error_str, but allows passing a format string with va_list args into this function. */

22
src/hidapi/windows/hid.c
View File

@ -255,15 +255,8 @@ static void free_hid_device(hid_device *dev)
static void register_winapi_error_to_buffer(wchar_t **error_buffer, const WCHAR *op) static void register_winapi_error_to_buffer(wchar_t **error_buffer, const WCHAR *op)
{ {
wchar_t *old_string; free(*error_buffer);
#ifdef HIDAPI_ATOMIC_SET_POINTER *error_buffer = NULL;
old_string = HIDAPI_ATOMIC_SET_POINTER(error_buffer, NULL);
#else
old_string = *error_buffer; *error_buffer = NULL;
#endif
if (old_string) {
free(old_string);
}
/* Only clear out error messages if NULL is passed into op */ /* Only clear out error messages if NULL is passed into op */
if (!op) { if (!op) {
@ -327,15 +320,8 @@ static void register_winapi_error_to_buffer(wchar_t **error_buffer, const WCHAR
static void register_string_error_to_buffer(wchar_t **error_buffer, const WCHAR *string_error) static void register_string_error_to_buffer(wchar_t **error_buffer, const WCHAR *string_error)
{ {
wchar_t *old_string; free(*error_buffer);
#ifdef HIDAPI_ATOMIC_SET_POINTER *error_buffer = NULL;
old_string = HIDAPI_ATOMIC_SET_POINTER(error_buffer, NULL);
#else
old_string = *error_buffer; *error_buffer = NULL;
#endif
if (old_string) {
free(old_string);
}
if (string_error) { if (string_error) {
*error_buffer = _wcsdup(string_error); *error_buffer = _wcsdup(string_error);