A race condition exists when parallel code accesses shared data without proper coordination. An attack that uses a race-condition weakness takes advantage of the unsafe data access to manipulate how one of the parallel sections of code reacts. Even though each process runs as intended, the outcome is unexpected. For example, consider a bank service that depends on an encryption key that it reads from a known location. An independent cryptography service is responsible for generating the key and placing it where the bank is expected to read it in a timely manner. If the bank and cryptography services do not coordinate with each other, then the bank may read a blank encryption key before cryptography writes the key to the location. This can effectively turn off all encryption for the bank without either service, or the administrator, knowing that something has gone wrong.
This accepts filename arguments; if an attacker can move those files, a race condition results..
The highlighted line of code below is the trigger point of this particular Alpine 3.6 race weakness.
* * Sure, it would be nicer to use a struct with 64-bit st_size and * 64-bit st_*time fields, but changing that now would break ABI. And * in MinGW, a plain "struct stat" is the one with 32-bit st_size and * st_*time fields. */ typedef struct _stat32 GStatBuf; #else typedef struct stat GStatBuf; #endif #if defined(G_OS_UNIX) && !defined(G_STDIO_NO_WRAP_ON_UNIX) /* Just pass on to the system functions, so there's no potential for data * format mismatches, especially with large file interfaces. * A few functions can't be handled in this way, since they are not defined * in a portable system header that we could include here. */ #ifndef __GTK_DOC_IGNORE__ #define g_chmod chmod #define g_open open #define g_creat creat #define g_rename rename #define g_mkdir mkdir #define g_stat stat #define g_lstat lstat #define g_remove remove #define g_fopen fopen #define g_freopen freopen #define g_utime utime #endif int g_access (const gchar *filename, int mode); int g_chdir (const gchar *path); int g_unlink (const gchar *filename); int g_rmdir (const gchar *filename); #else /* ! G_OS_UNIX */ /* Wrappers for C library functions that take pathname arguments. On * Unix, the pathname is a file name as it literally is in the file