Fix several problems with our ELF filters implementation.

Do not relocate twice an object which happens to be needed by loaded
binary (or dso) and some filtee opened due to symbol resolution when
relocating need objects.  Record the state of the relocation
processing in Obj_Entry and short-circuit relocate_objects() if
current object already processed.

Do not call constructors for filtees loaded during the early
relocation processing before image is initialized enough to run
user-provided code.  Filtees are loaded using dlopen_object(), which
normally performs relocation and initialization.  If filtee is
lazy-loaded during the relocation of dso needed by the main object,
dlopen_object() runs too earlier, when most runtime services are not
yet ready.

Postpone the constructors call to the time when main binary and
depended libraries constructors are run, passing the new flag
RTLD_LO_EARLY to dlopen_object().  Symbol lookups callers inform
symlook_* functions about early stage of initialization with
SYMLOOK_EARLY.  Pass flags through all functions participating in
object relocation.

Use the opportunity and fix flags argument to find_symdef() in
arch-specific reloc.c to use proper name SYMLOOK_IN_PLT instead of
true, which happen to have the same numeric value.

Reported and tested by:	theraven
Reviewed by:	kan
MFC after:	2 weeks

1 files changed, 8 insertions, 3 deletions

diff --git a/libexec/rtld-elf/rtld.h b/libexec/rtld-elf/rtld.h
index 9dfa0a2..2aabffe 100644
--- a/libexec/rtld-elf/rtld.h
+++ b/libexec/rtld-elf/rtld.h
@@ -229,6 +229,7 @@ typedef struct Struct_Obj_Entry {
 
     bool mainprog : 1;		/* True if this is the main program */
     bool rtld : 1;		/* True if this is the dynamic linker */
+    bool relocated : 1;		/* True if processed by relocate_objects() */
     bool textrel : 1;		/* True if there are relocations to text seg */
     bool symbolic : 1;		/* True if generated with "-Bsymbolic" */
     bool bind_now : 1;		/* True if all relocations should be made first */
@@ -267,6 +268,7 @@ typedef struct Struct_Obj_Entry {
 #define SYMLOOK_IN_PLT	0x01	/* Lookup for PLT symbol */
 #define SYMLOOK_DLSYM	0x02	/* Return newest versioned symbol. Used by
 				   dlsym. */
+#define	SYMLOOK_EARLY	0x04	/* Symlook is done during initialization. */
 
 /* Flags for load_object(). */
 #define	RTLD_LO_NOLOAD	0x01	/* dlopen() specified RTLD_NOLOAD. */
@@ -274,6 +276,8 @@ typedef struct Struct_Obj_Entry {
 #define	RTLD_LO_TRACE	0x04	/* Only tracing. */
 #define	RTLD_LO_NODELETE 0x08	/* Loaded object cannot be closed. */
 #define	RTLD_LO_FILTEES 0x10	/* Loading filtee. */
+#define	RTLD_LO_EARLY	0x20	/* Do not call ctors, postpone it to the
+				   initialization during the image start. */
 
 /*
  * Symbol cache entry used during relocation to avoid multiple lookups
@@ -353,11 +357,12 @@ const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long);
  * MD function declarations.
  */
 int do_copy_relocations(Obj_Entry *);
-int reloc_non_plt(Obj_Entry *, Obj_Entry *, struct Struct_RtldLockState *);
+int reloc_non_plt(Obj_Entry *, Obj_Entry *, int flags,
+    struct Struct_RtldLockState *);
 int reloc_plt(Obj_Entry *);
-int reloc_jmpslots(Obj_Entry *, struct Struct_RtldLockState *);
+int reloc_jmpslots(Obj_Entry *, int flags, struct Struct_RtldLockState *);
 int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *);
-int reloc_gnu_ifunc(Obj_Entry *, struct Struct_RtldLockState *);
+int reloc_gnu_ifunc(Obj_Entry *, int flags, struct Struct_RtldLockState *);
 void allocate_initial_tls(Obj_Entry *);
 
 #endif /* } */