From a33cb5feabfa95e8aecb75fc89a692dda10438cd Mon Sep 17 00:00:00 2001 From: Konstantin Belousov Date: Wed, 27 Jun 2012 20:24:25 +0000 Subject: [PATCH] Ensure that for the object which is a dependency for some filtee, 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 --- libexec/rtld-elf/rtld.c | 124 +++++++++++++++++++++++++++------------- 1 file changed, 84 insertions(+), 40 deletions(-) diff --git a/libexec/rtld-elf/rtld.c b/libexec/rtld-elf/rtld.c index 621d084b0ed8..723ba7cb65f8 100644 --- a/libexec/rtld-elf/rtld.c +++ b/libexec/rtld-elf/rtld.c @@ -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) {