Message ID | 87pnk7w3y3.fsf@oldenburg2.str.redhat.com |
---|---|
State | New |
Headers | show |
Series | elf: Assert that objects are relocated before their constructors run | expand |
On 9/11/19 5:57 AM, Florian Weimer wrote: > If we try to run constructors before relocation, this is always > a dynamic linker bug. An assert is easier to notice than a call > via an invalid function pointer (which may not even produce a valid > call stack). > > 2019-09-11 Florian Weimer <fweimer@redhat.com> > > * elf/dl-init.c (call_init): Assert that the object has been > relocated. OK for master. Reviewed-by: Carlos O'Donell <carlos@redhat.com> > diff --git a/elf/dl-init.c b/elf/dl-init.c > index 3721bca81e..a998992544 100644 > --- a/elf/dl-init.c > +++ b/elf/dl-init.c > @@ -16,6 +16,7 @@ > License along with the GNU C Library; if not, see > <https://www.gnu.org/licenses/>. */ > > +#include <assert.h> > #include <stddef.h> > #include <ldsodefs.h> > > @@ -27,6 +28,11 @@ typedef void (*init_t) (int, char **, char **); > static void > call_init (struct link_map *l, int argc, char **argv, char **env) > { > + /* If the object has not been relocated, this is a bug. The > + function pointers are invalid in this case. (Executables do not > + need relocation, and neither do proxy objects.) */ > + assert (l->l_real->l_relocated || l->l_real->l_type == lt_executable); OK. Use l_real for namespace support to work. > + > if (l->l_init_called) > /* This object is all done. */ > return; >
* Carlos O'Donell: > On 9/11/19 5:57 AM, Florian Weimer wrote: >> If we try to run constructors before relocation, this is always >> a dynamic linker bug. An assert is easier to notice than a call >> via an invalid function pointer (which may not even produce a valid >> call stack). >> >> 2019-09-11 Florian Weimer <fweimer@redhat.com> >> >> * elf/dl-init.c (call_init): Assert that the object has been >> relocated. > > OK for master. > > Reviewed-by: Carlos O'Donell <carlos@redhat.com> Thanks. I've finally pushed this. Thanks, Florian
diff --git a/elf/dl-init.c b/elf/dl-init.c index 3721bca81e..a998992544 100644 --- a/elf/dl-init.c +++ b/elf/dl-init.c @@ -16,6 +16,7 @@ License along with the GNU C Library; if not, see <https://www.gnu.org/licenses/>. */ +#include <assert.h> #include <stddef.h> #include <ldsodefs.h> @@ -27,6 +28,11 @@ typedef void (*init_t) (int, char **, char **); static void call_init (struct link_map *l, int argc, char **argv, char **env) { + /* If the object has not been relocated, this is a bug. The + function pointers are invalid in this case. (Executables do not + need relocation, and neither do proxy objects.) */ + assert (l->l_real->l_relocated || l->l_real->l_type == lt_executable); + if (l->l_init_called) /* This object is all done. */ return;