Implement support for ELF filters in rtld. Both normal and auxillary

filters are implemented.

Filtees are loaded on demand, unless LD_LOADFLTR environment variable
is set or -z loadfltr was specified during the linking. This forces
rtld to upgrade read-locked rtld_bind_lock to write lock when it
encounters an object with filter during symbol lookup.

Consolidate common arguments of the symbol lookup functions in the
SymLook structure.  Track the state of the rtld locks in the
RtldLockState structure. Pass local RtldLockState through the rtld
symbol lookup calls to allow lock upgrades.

Reviewed by:	kan
Tested by:	Mykola Dzham <i levsha me>, nwhitehorn (powerpc)

1 files changed, 24 insertions, 18 deletions

diff --git a/libexec/rtld-elf/i386/reloc.c b/libexec/rtld-elf/i386/reloc.c
index 818d2eb67a7e..9efebb32cd99 100644
--- a/libexec/rtld-elf/i386/reloc.c
+++ b/libexec/rtld-elf/i386/reloc.c
@@ -70,23 +70,28 @@ do_copy_relocations(Obj_Entry *dstobj)
 	    void *dstaddr;
 	    const Elf_Sym *dstsym;
 	    const char *name;
-	    unsigned long hash;
 	    size_t size;
 	    const void *srcaddr;
 	    const Elf_Sym *srcsym;
-	    const Ver_Entry *ve;
-	    Obj_Entry *srcobj;
+	    const Obj_Entry *srcobj, *defobj;
+	    SymLook req;
+	    int res;
 
 	    dstaddr = (void *) (dstobj->relocbase + rel->r_offset);
 	    dstsym = dstobj->symtab + ELF_R_SYM(rel->r_info);
 	    name = dstobj->strtab + dstsym->st_name;
-	    hash = elf_hash(name);
 	    size = dstsym->st_size;
-	    ve = fetch_ventry(dstobj, ELF_R_SYM(rel->r_info));
-
-	    for (srcobj = dstobj->next;  srcobj != NULL;  srcobj = srcobj->next)
-		if ((srcsym = symlook_obj(name, hash, srcobj, ve, 0)) != NULL)
+	    symlook_init(&req, name);
+	    req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rel->r_info));
+
+	    for (srcobj = dstobj->next;  srcobj != NULL;  srcobj = srcobj->next) {
+		res = symlook_obj(&req, srcobj);
+		if (res == 0) {
+		    srcsym = req.sym_out;
+		    defobj = req.defobj_out;
 		    break;
+		}
+	    }
 
 	    if (srcobj == NULL) {
 		_rtld_error("Undefined symbol \"%s\" referenced from COPY"
@@ -94,7 +99,7 @@ do_copy_relocations(Obj_Entry *dstobj)
 		return -1;
 	    }
 
-	    srcaddr = (const void *) (srcobj->relocbase + srcsym->st_value);
+	    srcaddr = (const void *) (defobj->relocbase + srcsym->st_value);
 	    memcpy(dstaddr, srcaddr, size);
 	}
     }
@@ -114,7 +119,7 @@ init_pltgot(Obj_Entry *obj)
 
 /* Process the non-PLT relocations. */
 int
-reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld)
+reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, RtldLockState *lockstate)
 {
 	const Elf_Rel *rellim;
 	const Elf_Rel *rel;
@@ -146,7 +151,7 @@ reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld)
 		    const Obj_Entry *defobj;
 
 		    def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj,
-		      false, cache);
+		      false, cache, lockstate);
 		    if (def == NULL)
 			goto done;
 
@@ -165,7 +170,7 @@ reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld)
 		    const Obj_Entry *defobj;
 
 		    def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj,
-		      false, cache);
+		      false, cache, lockstate);
 		    if (def == NULL)
 			goto done;
 
@@ -195,7 +200,7 @@ reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld)
 		    const Obj_Entry *defobj;
 
 		    def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj,
-		      false, cache);
+		      false, cache, lockstate);
 		    if (def == NULL)
 			goto done;
 
@@ -213,7 +218,7 @@ reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld)
 		    const Obj_Entry *defobj;
 
 		    def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj,
-		      false, cache);
+		      false, cache, lockstate);
 		    if (def == NULL)
 			goto done;
 
@@ -243,7 +248,7 @@ reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld)
 		    const Obj_Entry *defobj;
 
 		    def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj,
-		      false, cache);
+		      false, cache, lockstate);
 		    if (def == NULL)
 			goto done;
 
@@ -257,7 +262,7 @@ reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld)
 		    const Obj_Entry *defobj;
 
 		    def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj,
-		      false, cache);
+		      false, cache, lockstate);
 		    if (def == NULL)
 			goto done;
 
@@ -301,7 +306,7 @@ reloc_plt(Obj_Entry *obj)
 
 /* Relocate the jump slots in an object. */
 int
-reloc_jmpslots(Obj_Entry *obj)
+reloc_jmpslots(Obj_Entry *obj, RtldLockState *lockstate)
 {
     const Elf_Rel *rellim;
     const Elf_Rel *rel;
@@ -316,7 +321,8 @@ reloc_jmpslots(Obj_Entry *obj)
 
 	assert(ELF_R_TYPE(rel->r_info) == R_386_JMP_SLOT);
 	where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
-	def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL);
+	def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
+	    lockstate);
 	if (def == NULL)
 	    return -1;
 	target = (Elf_Addr)(defobj->relocbase + def->st_value);