diff options
| author | Florian Weimer <fweimer@redhat.com> | 2016-06-23 20:01:40 +0200 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2016-06-23 20:01:52 +0200 |
| commit | db3476aff19b75c4fdefbe65fcd5f0a90588ba51 (patch) | |
| tree | 5cefd4971a0e6b5d5f9eacf6d3532c6aedc7b352 /debug | |
| parent | 64ba17317dc9343f0958755ad04af71ec3da637b (diff) | |
libio: Implement vtable verification [BZ #20191]
This commit puts all libio vtables in a dedicated, read-only ELF
section, so that they are consecutive in memory. Before any indirect
jump, the vtable pointer is checked against the section boundaries,
and the process is terminated if the vtable pointer does not fall into
the special ELF section.
To enable backwards compatibility, a special flag variable
(_IO_accept_foreign_vtables), protected by the pointer guard, avoids
process termination if libio stream object constructor functions have
been called earlier. Such constructor functions are called by the GCC
2.95 libstdc++ library, and this mechanism ensures compatibility with
old binaries. Existing callers inside glibc of these functions are
adjusted to call the original functions, not the wrappers which enable
vtable compatiblity.
The compatibility mechanism is used to enable passing FILE * objects
across a static dlopen boundary, too.
Diffstat (limited to 'debug')
| -rw-r--r-- | debug/obprintf_chk.c | 2 | ||||
| -rw-r--r-- | debug/vdprintf_chk.c | 2 | ||||
| -rw-r--r-- | debug/vsnprintf_chk.c | 2 | ||||
| -rw-r--r-- | debug/vsprintf_chk.c | 2 |
4 files changed, 4 insertions, 4 deletions
diff --git a/debug/obprintf_chk.c b/debug/obprintf_chk.c index 8469b5f675..09655ba7a3 100644 --- a/debug/obprintf_chk.c +++ b/debug/obprintf_chk.c @@ -35,7 +35,7 @@ struct _IO_obstack_file struct obstack *obstack; }; -extern const struct _IO_jump_t _IO_obstack_jumps attribute_hidden; +extern const struct _IO_jump_t _IO_obstack_jumps libio_vtable attribute_hidden; int __obstack_vprintf_chk (struct obstack *obstack, int flags, const char *format, diff --git a/debug/vdprintf_chk.c b/debug/vdprintf_chk.c index 05d0bcd7e7..ce0ddb028c 100644 --- a/debug/vdprintf_chk.c +++ b/debug/vdprintf_chk.c @@ -39,7 +39,7 @@ __vdprintf_chk (int d, int flags, const char *format, va_list arg) #endif _IO_no_init (&tmpfil.file, _IO_USER_LOCK, 0, &wd, &_IO_wfile_jumps); _IO_JUMPS (&tmpfil) = &_IO_file_jumps; - _IO_file_init (&tmpfil); + _IO_new_file_init_internal (&tmpfil); #if !_IO_UNIFIED_JUMPTABLES tmpfil.vtable = NULL; #endif diff --git a/debug/vsnprintf_chk.c b/debug/vsnprintf_chk.c index cc559d2b1d..a6bb051234 100644 --- a/debug/vsnprintf_chk.c +++ b/debug/vsnprintf_chk.c @@ -20,7 +20,7 @@ #include "../libio/libioP.h" #include "../libio/strfile.h" -extern const struct _IO_jump_t _IO_strn_jumps attribute_hidden; +extern const struct _IO_jump_t _IO_strn_jumps libio_vtable attribute_hidden; /* Write formatted output into S, according to the format string FORMAT, writing no more than MAXLEN characters. */ diff --git a/debug/vsprintf_chk.c b/debug/vsprintf_chk.c index aa1587ce6f..02e7372849 100644 --- a/debug/vsprintf_chk.c +++ b/debug/vsprintf_chk.c @@ -32,7 +32,7 @@ _IO_str_chk_overflow (_IO_FILE *fp, int c) } -static const struct _IO_jump_t _IO_str_chk_jumps = +static const struct _IO_jump_t _IO_str_chk_jumps libio_vtable = { JUMP_INIT_DUMMY, JUMP_INIT(finish, _IO_str_finish), |