#include <errno.h>
#include <libintl.h>
#include <ldsodefs.h>
+#include <sys/mman.h>
-static void
-enable_bti (struct link_map *map, const char *program)
+/* See elf/dl-load.h. */
+#ifndef MAP_COPY
+# define MAP_COPY (MAP_PRIVATE | MAP_DENYWRITE)
+#endif
+
+/* Enable BTI protection for MAP. */
+
+void
+_dl_bti_protect (struct link_map *map, int fd)
{
const size_t pagesz = GLRO(dl_pagesize);
const ElfW(Phdr) *phdr;
if (phdr->p_flags & PF_W)
prot |= PROT_WRITE;
- if (__mprotect (start, len, prot) < 0)
- {
- if (program)
- _dl_fatal_printf ("%s: mprotect failed to turn on BTI\n",
- map->l_name);
- else
- _dl_signal_error (errno, map->l_name, "dlopen",
- N_("mprotect failed to turn on BTI"));
- }
+ if (fd == -1)
+ /* Ignore failures for kernel mapped binaries. */
+ __mprotect (start, len, prot);
+ else
+ map->l_mach.bti_fail = __mmap (start, len, prot,
+ MAP_FIXED|MAP_COPY|MAP_FILE,
+ fd, off) == MAP_FAILED;
}
}
+
+static void
+bti_failed (struct link_map *l, const char *program)
+{
+ if (program)
+ _dl_fatal_printf ("%s: %s: failed to turn on BTI protection\n",
+ program, l->l_name);
+ else
+ /* Note: the errno value is not available any more. */
+ _dl_signal_error (0, l->l_name, "dlopen",
+ N_("failed to turn on BTI protection"));
+}
+
+
/* Enable BTI for L and its dependencies. */
void
if (!GLRO(dl_aarch64_cpu_features).bti)
return;
- if (l->l_mach.bti)
- enable_bti (l, program);
+ if (l->l_mach.bti_fail)
+ bti_failed (l, program);
unsigned int i = l->l_searchlist.r_nlist;
while (i-- > 0)
{
struct link_map *dep = l->l_initfini[i];
- if (dep->l_init_called)
- continue;
- if (dep->l_mach.bti)
- enable_bti (dep, program);
+ if (dep->l_mach.bti_fail)
+ bti_failed (dep, program);
}
}
#ifndef _DL_PROP_H
#define _DL_PROP_H
+extern void _dl_bti_protect (struct link_map *, int) attribute_hidden;
+
extern void _dl_bti_check (struct link_map *, const char *)
attribute_hidden;
_dl_process_gnu_property (struct link_map *l, int fd, uint32_t type,
uint32_t datasz, void *data)
{
+ if (!GLRO(dl_aarch64_cpu_features).bti)
+ /* Skip note processing. */
+ return 0;
+
if (type == GNU_PROPERTY_AARCH64_FEATURE_1_AND)
{
/* Stop if the property note is ill-formed. */
unsigned int feature_1 = *(unsigned int *) data;
if (feature_1 & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)
- l->l_mach.bti = true;
+ _dl_bti_protect (l, fd);
/* Stop if we processed the property note. */
return 0;