diff options
Diffstat (limited to 'libc/sysdeps/linux/common/ssp.c')
| -rw-r--r-- | libc/sysdeps/linux/common/ssp.c | 73 |
1 files changed, 45 insertions, 28 deletions
diff --git a/libc/sysdeps/linux/common/ssp.c b/libc/sysdeps/linux/common/ssp.c index ecfc67e5e..31833cbb9 100644 --- a/libc/sysdeps/linux/common/ssp.c +++ b/libc/sysdeps/linux/common/ssp.c @@ -20,6 +20,10 @@ # include <config.h> #endif +#ifdef __SSP__ +# error ssp.c has to be built w/ -fno-stack-protector +#endif + #include <stdio.h> #include <string.h> #include <fcntl.h> @@ -30,29 +34,38 @@ #include <sys/syslog.h> #include <sys/time.h> #ifdef __SSP_USE_ERANDOM__ -#include <sys/sysctl.h> +# include <sys/sysctl.h> #endif #ifdef __PROPOLICE_BLOCK_SEGV__ -#define SSP_SIGTYPE SIGSEGV +# define SSP_SIGTYPE SIGSEGV #elif __PROPOLICE_BLOCK_KILL__ -#define SSP_SIGTYPE SIGKILL +# define SSP_SIGTYPE SIGKILL #else -#define SSP_SIGTYPE SIGABRT +# define SSP_SIGTYPE SIGABRT #endif -/* prototypes */ -extern int __libc_open (__const char *file, int oflag, mode_t mode); -extern ssize_t __libc_read(int fd, void *buf, size_t count); -extern int __libc_close (int fd); - unsigned long __guard = 0UL; +/* Use of __* functions from the rest of glibc here avoids + * initialisation problems for executables preloaded with + * libraries that overload the associated standard library + * functions. + */ +#ifdef __UCLIBC__ +extern int __libc_open(__const char *file, int flags, ...); +extern ssize_t __libc_read(int fd, void *buf, size_t count); +extern int __libc_close(int fd); +#else +# define __libc_open(file, flags) __open(file, flags) +# define __libc_read(fd, buf, count) __read(fd, buf, count) +# define __libc_close(fd) __close(fd) +#endif + void __guard_setup(void) __attribute__ ((constructor)); void __guard_setup(void) { size_t size; - struct timeval tv; if (__guard != 0UL) return; @@ -61,18 +74,20 @@ void __guard_setup(void) __guard = 0xFF0A0D00UL; #ifndef __SSP_QUICK_CANARY__ -#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 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__ */ /* * Attempt to open kernel pseudo random device if one exists before * opening urandom to avoid system entropy depletion. @@ -80,9 +95,9 @@ void __guard_setup(void) { int fd; -#ifdef __SSP_USE_ERANDOM__ +# ifdef __SSP_USE_ERANDOM__ if ((fd = __libc_open("/dev/erandom", O_RDONLY)) == (-1)) -#endif +# endif fd = __libc_open("/dev/urandom", O_RDONLY); if (fd != (-1)) { size = __libc_read(fd, (char *) &__guard, sizeof(__guard)); @@ -91,13 +106,15 @@ void __guard_setup(void) return; } } -#endif +#endif /* ifndef __SSP_QUICK_CANARY__ */ /* Everything failed? Or we are using a weakened model of the * terminator canary */ - - gettimeofday(&tv, NULL); - __guard ^= tv.tv_usec ^ tv.tv_sec; + { + struct timeval tv; + gettimeofday(&tv, NULL); + __guard ^= tv.tv_usec ^ tv.tv_sec; + } } void __stack_smash_handler(char func[], int damaged __attribute__ ((unused))); |