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Ensure that for the object which is a dependency for some filtee,

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relocations are performed before the object's initializer is called.
When dlopen()ing an object, relocate the whole DAG rooted in the
object instead of only relocating the object itself and list of newly
loaded dependencies.

Reversed sequence currently can occur if the same object is a
dependency for both filtee and filter, since filtees are loaded
typically during the relocation processing, when some filter
dependencies might be already loaded but not relocated yet.

Reported and tested by:	swills
Reviewed by:	kan
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2012-06-27 20:24:25 +00:00
parent 77db8b179b
commit a33cb5feab
1 changed files with 84 additions and 40 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

124
libexec/rtld-elf/rtld.c
View File

@ -117,6 +117,10 @@ static void objlist_push_head(Objlist *, Obj_Entry *);
static void objlist_push_tail(Objlist *, Obj_Entry *);
static void objlist_remove(Objlist *, Obj_Entry *);
static void *path_enumerate(const char *, path_enum_proc, void *);
static int relocate_object_dag(Obj_Entry *root, bool bind_now,
Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
int flags, RtldLockState *lockstate);
static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
RtldLockState *);
static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
@ -2217,52 +2221,70 @@ objlist_remove(Objlist *list, Obj_Entry *obj)
}
/*
* Relocate newly-loaded shared objects. The argument is a pointer to
* the Obj_Entry for the first such object. All objects from the first
* to the end of the list of objects are relocated. Returns 0 on success,
* or -1 on failure.
* Relocate dag rooted in the specified object.
* Returns 0 on success, or -1 on failure.
*/
static int
relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
int flags, RtldLockState *lockstate)
{
Objlist_Entry *elm;
int error;
error = 0;
STAILQ_FOREACH(elm, &root->dagmembers, link) {
error = relocate_object(elm->obj, bind_now, rtldobj, flags,
lockstate);
if (error == -1)
break;
}
return (error);
}
/*
* Relocate single object.
* Returns 0 on success, or -1 on failure.
*/
static int
relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
int flags, RtldLockState *lockstate)
{
Obj_Entry *obj;
for (obj = first; obj != NULL; obj = obj->next) {
if (obj->relocated)
continue;
return (0);
obj->relocated = true;
if (obj != rtldobj)
dbg("relocating \"%s\"", obj->path);
dbg("relocating \"%s\"", obj->path);
if (obj->symtab == NULL || obj->strtab == NULL ||
!(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
_rtld_error("%s: Shared object has no run-time symbol table",
obj->path);
return -1;
!(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
_rtld_error("%s: Shared object has no run-time symbol table",
obj->path);
return (-1);
}
if (obj->textrel) {
/* There are relocations to the write-protected text segment. */
if (mprotect(obj->mapbase, obj->textsize,
PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
_rtld_error("%s: Cannot write-enable text segment: %s",
obj->path, rtld_strerror(errno));
return -1;
}
/* There are relocations to the write-protected text segment. */
if (mprotect(obj->mapbase, obj->textsize,
PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
_rtld_error("%s: Cannot write-enable text segment: %s",
obj->path, rtld_strerror(errno));
return (-1);
}
}
/* Process the non-PLT relocations. */
if (reloc_non_plt(obj, rtldobj, flags, lockstate))
return -1;
return (-1);
if (obj->textrel) { /* Re-protected the text segment. */
if (mprotect(obj->mapbase, obj->textsize,
PROT_READ|PROT_EXEC) == -1) {
_rtld_error("%s: Cannot write-protect text segment: %s",
obj->path, rtld_strerror(errno));
return -1;
}
if (mprotect(obj->mapbase, obj->textsize,
PROT_READ|PROT_EXEC) == -1) {
_rtld_error("%s: Cannot write-protect text segment: %s",
obj->path, rtld_strerror(errno));
return (-1);
}
}
@ -2271,18 +2293,19 @@ relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
/* Process the PLT relocations. */
if (reloc_plt(obj) == -1)
return -1;
return (-1);
/* Relocate the jump slots if we are doing immediate binding. */
if (obj->bind_now || bind_now)
if (reloc_jmpslots(obj, flags, lockstate) == -1)
return -1;
if (reloc_jmpslots(obj, flags, lockstate) == -1)
return (-1);
if (obj->relro_size > 0) {
if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) {
_rtld_error("%s: Cannot enforce relro protection: %s",
obj->path, rtld_strerror(errno));
return -1;
}
if (mprotect(obj->relro_page, obj->relro_size,
PROT_READ) == -1) {
_rtld_error("%s: Cannot enforce relro protection: %s",
obj->path, rtld_strerror(errno));
return (-1);
}
}
/*
@ -2292,9 +2315,30 @@ relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
*/
obj->magic = RTLD_MAGIC;
obj->version = RTLD_VERSION;
}
return (0);
return (0);
}
/*
* Relocate newly-loaded shared objects. The argument is a pointer to
* the Obj_Entry for the first such object. All objects from the first
* to the end of the list of objects are relocated. Returns 0 on success,
* or -1 on failure.
*/
static int
relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
int flags, RtldLockState *lockstate)
{
Obj_Entry *obj;
int error;
for (error = 0, obj = first; obj != NULL; obj = obj->next) {
error = relocate_object(obj, bind_now, rtldobj, flags,
lockstate);
if (error == -1)
break;
}
return (error);
}
/*
@ -2614,10 +2658,10 @@ dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
result = rtld_verify_versions(&obj->dagmembers);
if (result != -1 && ld_tracing)
goto trace;
if (result == -1 || (relocate_objects(obj,
(mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
if (result == -1 || relocate_object_dag(obj,
(mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
(lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
lockstate)) == -1) {
lockstate) == -1) {
dlopen_cleanup(obj);
obj = NULL;
} else if (lo_flags & RTLD_LO_EARLY) {