diff options
Diffstat (limited to 'libio/libioP.h')
| -rw-r--r-- | libio/libioP.h | 76 |
1 files changed, 63 insertions, 13 deletions
diff --git a/libio/libioP.h b/libio/libioP.h index 8706af2..54dc35c 100644 --- a/libio/libioP.h +++ b/libio/libioP.h @@ -125,11 +125,12 @@ extern "C" { #if _IO_JUMPS_OFFSET # define _IO_JUMPS_FUNC(THIS) \ - (*(struct _IO_jump_t **) ((void *) &_IO_JUMPS_FILE_plus (THIS) \ - + (THIS)->_vtable_offset)) + (IO_validate_vtable \ + (*(struct _IO_jump_t **) ((void *) &_IO_JUMPS_FILE_plus (THIS) \ + + (THIS)->_vtable_offset))) # define _IO_vtable_offset(THIS) (THIS)->_vtable_offset #else -# define _IO_JUMPS_FUNC(THIS) _IO_JUMPS_FILE_plus (THIS) +# define _IO_JUMPS_FUNC(THIS) (IO_validate_vtable (_IO_JUMPS_FILE_plus (THIS))) # define _IO_vtable_offset(THIS) 0 #endif #define _IO_WIDE_JUMPS_FUNC(THIS) _IO_WIDE_JUMPS(THIS) @@ -378,8 +379,7 @@ extern void _IO_switch_to_main_get_area (_IO_FILE *) __THROW; extern void _IO_switch_to_backup_area (_IO_FILE *) __THROW; extern int _IO_switch_to_get_mode (_IO_FILE *); libc_hidden_proto (_IO_switch_to_get_mode) -extern void _IO_init (_IO_FILE *, int) __THROW; -libc_hidden_proto (_IO_init) +extern void _IO_init_internal (_IO_FILE *, int) attribute_hidden; extern int _IO_sputbackc (_IO_FILE *, int) __THROW; libc_hidden_proto (_IO_sputbackc) extern int _IO_sungetc (_IO_FILE *) __THROW; @@ -587,8 +587,6 @@ extern int _IO_file_underflow_maybe_mmap (_IO_FILE *); extern int _IO_file_overflow (_IO_FILE *, int); libc_hidden_proto (_IO_file_overflow) #define _IO_file_is_open(__fp) ((__fp)->_fileno != -1) -extern void _IO_file_init (struct _IO_FILE_plus *) __THROW; -libc_hidden_proto (_IO_file_init) extern _IO_FILE* _IO_file_attach (_IO_FILE *, int); libc_hidden_proto (_IO_file_attach) extern _IO_FILE* _IO_file_open (_IO_FILE *, const char *, int, int, int, int); @@ -614,7 +612,8 @@ extern _IO_FILE* _IO_new_file_fopen (_IO_FILE *, const char *, const char *, int); extern void _IO_no_init (_IO_FILE *, int, int, struct _IO_wide_data *, const struct _IO_jump_t *) __THROW; -extern void _IO_new_file_init (struct _IO_FILE_plus *) __THROW; +extern void _IO_new_file_init_internal (struct _IO_FILE_plus *) + __THROW attribute_hidden; extern _IO_FILE* _IO_new_file_setbuf (_IO_FILE *, char *, _IO_ssize_t); extern _IO_FILE* _IO_file_setbuf_mmap (_IO_FILE *, char *, _IO_ssize_t); extern int _IO_new_file_sync (_IO_FILE *); @@ -629,7 +628,8 @@ extern _IO_off64_t _IO_old_file_seekoff (_IO_FILE *, _IO_off64_t, int, int); extern _IO_size_t _IO_old_file_xsputn (_IO_FILE *, const void *, _IO_size_t); extern int _IO_old_file_underflow (_IO_FILE *); extern int _IO_old_file_overflow (_IO_FILE *, int); -extern void _IO_old_file_init (struct _IO_FILE_plus *) __THROW; +extern void _IO_old_file_init_internal (struct _IO_FILE_plus *) + __THROW attribute_hidden; extern _IO_FILE* _IO_old_file_attach (_IO_FILE *, int); extern _IO_FILE* _IO_old_file_fopen (_IO_FILE *, const char *, const char *); extern _IO_ssize_t _IO_old_file_write (_IO_FILE *, const void *, _IO_ssize_t); @@ -673,10 +673,6 @@ extern void _IO_str_finish (_IO_FILE *, int) __THROW; /* Other strfile functions */ struct _IO_strfile_; -extern void _IO_str_init_static (struct _IO_strfile_ *, char *, int, char *) - __THROW; -extern void _IO_str_init_readonly (struct _IO_strfile_ *, const char *, int) - __THROW; extern _IO_ssize_t _IO_str_count (_IO_FILE *) __THROW; /* And the wide character versions. */ @@ -890,3 +886,57 @@ _IO_acquire_lock_clear_flags2_fct (_IO_FILE **p) | _IO_FLAGS2_SCANF_STD); \ } while (0) #endif + +/* Collect all vtables in a special section for vtable verification. + These symbols cover the extent of this section. */ +symbol_set_declare (__libc_IO_vtables) + +/* libio vtables need to carry this attribute so that they pass + validation. */ +#define libio_vtable __attribute__ ((section ("__libc_IO_vtables"))) + +#ifdef SHARED +/* If equal to &_IO_vtable_check (with pointer guard protection), + unknown vtable pointers are valid. This function pointer is solely + used as a flag. */ +extern void (*IO_accept_foreign_vtables) (void) attribute_hidden; + +/* Assigns the passed function pointer (either NULL or + &_IO_vtable_check) to IO_accept_foreign_vtables. */ +static inline void +IO_set_accept_foreign_vtables (void (*flag) (void)) +{ + PTR_MANGLE (flag); + atomic_store_relaxed (&IO_accept_foreign_vtables, flag); +} + +#else /* !SHARED */ + +/* The statically-linked version does nothing. */ +static inline void +IO_set_accept_foreign_vtables (void (*flag) (void)) +{ +} + +#endif + +/* Check if unknown vtable pointers are permitted; otherwise, + terminate the process. */ +void _IO_vtable_check (void) attribute_hidden; + +/* Perform vtable pointer validation. If validation fails, terminate + the process. */ +static inline const struct _IO_jump_t * +IO_validate_vtable (const struct _IO_jump_t *vtable) +{ + /* Fast path: The vtable pointer is within the __libc_IO_vtables + section. */ + uintptr_t section_length = __stop___libc_IO_vtables - __start___libc_IO_vtables; + const char *ptr = (const char *) vtable; + uintptr_t offset = ptr - __start___libc_IO_vtables; + if (__glibc_unlikely (offset >= section_length)) + /* The vtable pointer is not in the expected section. Use the + slow path, which will terminate the process if necessary. */ + _IO_vtable_check (); + return vtable; +} |