diff options
Diffstat (limited to 'libc/misc/internals')
| -rw-r--r-- | libc/misc/internals/__uClibc_main.c | 69 |
1 files changed, 63 insertions, 6 deletions
diff --git a/libc/misc/internals/__uClibc_main.c b/libc/misc/internals/__uClibc_main.c index 167b77a33..c88649def 100644 --- a/libc/misc/internals/__uClibc_main.c +++ b/libc/misc/internals/__uClibc_main.c @@ -26,9 +26,10 @@ #include <sys/stat.h> #include <sys/sysmacros.h> #ifdef __UCLIBC_HAS_SSP__ -extern void __guard_setup(void); -#endif +#include <ssp-internal.h> +unsigned long __guard = 0UL; +#endif /* * Prototypes. @@ -105,6 +106,62 @@ static int __check_suid(void) return 1; } +#ifdef __UCLIBC_HAS_SSP__ +static __always_inline void __guard_setup(void) +{ + if (__guard != 0UL) + return; + +#ifndef __SSP_QUICK_CANARY__ + + size_t size; + +# ifdef __SSP_USE_ERANDOM__ + { + int mib[3]; + /* Random is another depth in Linux, hence an array of 3. */ + mib[0] = CTL_KERN; + mib[1] = KERN_RANDOM; + mib[2] = RANDOM_ERANDOM; + + size = sizeof(unsigned long); + if (SYSCTL(mib, 3, &__guard, &size, NULL, 0) != (-1)) + if (__guard != 0UL) + return; + } +# endif /* ifdef __SSP_USE_ERANDOM__ */ + { + int fd; + +# ifdef __SSP_USE_ERANDOM__ + /* + * Attempt to open kernel pseudo random device if one exists before + * opening urandom to avoid system entropy depletion. + */ + if ((fd = OPEN("/dev/erandom", O_RDONLY)) == (-1)) +# endif + fd = OPEN("/dev/urandom", O_RDONLY); + if (fd != (-1)) { + size = READ(fd, (char *) &__guard, sizeof(__guard)); + CLOSE(fd); + if (size == sizeof(__guard)) + return; + } + } +#endif /* ifndef __SSP_QUICK_CANARY__ */ + + /* Start with the "terminator canary". */ + __guard = 0xFF0A0D00UL; + + /* Everything failed? Or we are using a weakened model of the + * terminator canary */ + { + struct timeval tv; + GETTIMEOFDAY(&tv, NULL); + __guard ^= tv.tv_usec ^ tv.tv_sec; + } +} +#endif /* __UCLIBC_HAS_SSP__ */ /* __uClibc_init completely initialize uClibc so it is ready to use. * @@ -140,6 +197,10 @@ void __uClibc_init(void) __pthread_initialize_minimal(); #endif +#ifdef __UCLIBC_HAS_SSP__ + __guard_setup (); +#endif + #ifdef __UCLIBC_HAS_LOCALE__ /* Initialize the global locale structure. */ if (likely(_locale_init!=NULL)) @@ -235,10 +296,6 @@ __uClibc_main(int (*main)(int, char **, char **), int argc, } #endif -#ifdef __UCLIBC_HAS_SSP__ - __guard_setup (); -#endif - /* Note: It is possible that any initialization done above could * have resulted in errno being set nonzero, so set it to 0 before * we call main. |