freebsd-dev/sys/kern/link_elf_obj.c

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/*-
* Copyright (c) 1998-2000 Doug Rabson
* Copyright (c) 2004 Peter Wemm
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
2003-06-11 00:56:59 +00:00
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mac.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/namei.h>
#include <sys/fcntl.h>
#include <sys/vnode.h>
#include <sys/linker.h>
#include <machine/elf.h>
1998-09-11 08:46:15 +00:00
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_object.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <sys/link_elf.h>
1998-09-11 08:46:15 +00:00
#include "linker_if.h"
typedef struct {
void *addr;
Elf_Off size;
int flags;
int sec; /* Original section */
char *name;
} Elf_progent;
typedef struct {
Elf_Rel *rel;
int nrel;
int sec;
} Elf_relent;
typedef struct {
Elf_Rela *rela;
int nrela;
int sec;
} Elf_relaent;
typedef struct elf_file {
struct linker_file lf; /* Common fields */
int preloaded;
caddr_t address; /* Relocation address */
vm_object_t object; /* VM object to hold file pages */
Elf_Shdr *e_shdr;
Elf_progent *progtab;
int nprogtab;
Elf_relaent *relatab;
int nrela;
Elf_relent *reltab;
int nrel;
Elf_Sym *ddbsymtab; /* The symbol table we are using */
long ddbsymcnt; /* Number of symbols */
caddr_t ddbstrtab; /* String table */
long ddbstrcnt; /* number of bytes in string table */
caddr_t shstrtab; /* Section name string table */
long shstrcnt; /* number of bytes in string table */
} *elf_file_t;
First round implementation of a fine grain enhanced module to module version dependency system. This isn't quite finished, but it is at a useful stage to do a functional checkpoint. Highlights: - version and dependency metadata is gathered via linker sets, so things are handled the same for static kernels and code built to live in a kld. - The dependencies are at module level (versus at file level). - Dependencies determine kld symbol search order - this means that you cannot link against symbols in another file unless you depend on it. This is so that you cannot accidently unload the target out from underneath the ones referencing it. - It is flexible enough that we can put tags in #include files and macros so that we can get decent hooks for enforcing recompiles on incompatable ABI changes. eg: if we change struct proc, we could force a recompile for all kld's that reference the proc struct. - Tangled dependency references at boot time are sorted. Files are relocated once all their dependencies are already relocated. Caveats: - Loader support is incomplete, but has been worked on seperately. - Actual enforcement of the version number tags is not active yet - just the module dependencies are live. The actual structure of versioning hasn't been agreed on yet. (eg: major.minor, or whatever) - There is some backwards compatability for old modules without metadata but I'm not sure how good it is. This is based on work originally done by Boris Popov (bp@freebsd.org), but I'm not sure he'd recognize much of it now. Don't blame him. :-) Also, ideas have been borrowed from Mike Smith.
2000-04-29 13:19:31 +00:00
static int link_elf_link_preload(linker_class_t cls,
const char *, linker_file_t *);
First round implementation of a fine grain enhanced module to module version dependency system. This isn't quite finished, but it is at a useful stage to do a functional checkpoint. Highlights: - version and dependency metadata is gathered via linker sets, so things are handled the same for static kernels and code built to live in a kld. - The dependencies are at module level (versus at file level). - Dependencies determine kld symbol search order - this means that you cannot link against symbols in another file unless you depend on it. This is so that you cannot accidently unload the target out from underneath the ones referencing it. - It is flexible enough that we can put tags in #include files and macros so that we can get decent hooks for enforcing recompiles on incompatable ABI changes. eg: if we change struct proc, we could force a recompile for all kld's that reference the proc struct. - Tangled dependency references at boot time are sorted. Files are relocated once all their dependencies are already relocated. Caveats: - Loader support is incomplete, but has been worked on seperately. - Actual enforcement of the version number tags is not active yet - just the module dependencies are live. The actual structure of versioning hasn't been agreed on yet. (eg: major.minor, or whatever) - There is some backwards compatability for old modules without metadata but I'm not sure how good it is. This is based on work originally done by Boris Popov (bp@freebsd.org), but I'm not sure he'd recognize much of it now. Don't blame him. :-) Also, ideas have been borrowed from Mike Smith.
2000-04-29 13:19:31 +00:00
static int link_elf_link_preload_finish(linker_file_t);
static int link_elf_load_file(linker_class_t, const char *, linker_file_t *);
static int link_elf_lookup_symbol(linker_file_t, const char *,
c_linker_sym_t *);
static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
linker_symval_t *);
static int link_elf_search_symbol(linker_file_t, caddr_t value,
c_linker_sym_t *sym, long *diffp);
static void link_elf_unload_file(linker_file_t);
static int link_elf_lookup_set(linker_file_t, const char *,
void ***, void ***, int *);
static int link_elf_each_function_name(linker_file_t,
int (*)(const char *, void *), void *);
static void link_elf_reloc_local(linker_file_t);
static Elf_Addr elf_obj_lookup(linker_file_t lf, Elf_Word symidx, int deps);
static kobj_method_t link_elf_methods[] = {
KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
KOBJMETHOD(linker_unload, link_elf_unload_file),
KOBJMETHOD(linker_load_file, link_elf_load_file),
KOBJMETHOD(linker_link_preload, link_elf_link_preload),
KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
{ 0, 0 }
};
static struct linker_class link_elf_class = {
#if ELF_TARG_CLASS == ELFCLASS32
"elf32_obj",
#else
"elf64_obj",
#endif
link_elf_methods, sizeof(struct elf_file)
};
static int relocate_file(elf_file_t ef);
static void
link_elf_error(const char *s)
{
printf("kldload: %s\n", s);
}
static void
link_elf_init(void *arg)
{
linker_add_class(&link_elf_class);
}
SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
static int
link_elf_link_preload(linker_class_t cls, const char *filename,
linker_file_t *result)
{
Elf_Ehdr *hdr;
Elf_Shdr *shdr;
Elf_Sym *es;
void *modptr, *baseptr, *sizeptr;
char *type;
elf_file_t ef;
linker_file_t lf;
Elf_Addr off;
int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
/* Look to see if we have the file preloaded */
modptr = preload_search_by_name(filename);
if (modptr == NULL)
return ENOENT;
type = (char *)preload_search_info(modptr, MODINFO_TYPE);
baseptr = preload_search_info(modptr, MODINFO_ADDR);
sizeptr = preload_search_info(modptr, MODINFO_SIZE);
hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
MODINFOMD_ELFHDR);
shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
MODINFOMD_SHDR);
if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
" obj module") != 0 &&
strcmp(type, "elf obj module") != 0)) {
return (EFTYPE);
}
if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
shdr == NULL)
return (EINVAL);
lf = linker_make_file(filename, &link_elf_class);
if (lf == NULL)
return (ENOMEM);
ef = (elf_file_t)lf;
ef->preloaded = 1;
ef->address = *(caddr_t *)baseptr;
lf->address = *(caddr_t *)baseptr;
lf->size = *(size_t *)sizeptr;
if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
hdr->e_ident[EI_VERSION] != EV_CURRENT ||
hdr->e_version != EV_CURRENT ||
hdr->e_type != ET_REL ||
hdr->e_machine != ELF_TARG_MACH) {
error = EFTYPE;
goto out;
}
ef->e_shdr = shdr;
/* Scan the section header for information and table sizing. */
symtabindex = -1;
symstrindex = -1;
for (i = 0; i < hdr->e_shnum; i++) {
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
ef->nprogtab++;
break;
case SHT_SYMTAB:
symtabindex = i;
symstrindex = shdr[i].sh_link;
break;
case SHT_REL:
ef->nrel++;
break;
case SHT_RELA:
ef->nrela++;
break;
}
}
shstrindex = hdr->e_shstrndx;
if (ef->nprogtab == 0 || symstrindex < 0 ||
symstrindex >= hdr->e_shnum ||
shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
shstrindex >= hdr->e_shnum ||
shdr[shstrindex].sh_type != SHT_STRTAB) {
printf("%s: bad/missing section headers\n", filename);
error = ENOEXEC;
goto out;
}
/* Allocate space for tracking the load chunks */
if (ef->nprogtab != 0)
ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
M_LINKER, M_WAITOK | M_ZERO);
if (ef->nrel != 0)
ef->reltab = malloc(ef->nrel * sizeof(*ef->reltab), M_LINKER,
M_WAITOK | M_ZERO);
if (ef->nrela != 0)
ef->relatab = malloc(ef->nrela * sizeof(*ef->relatab), M_LINKER,
M_WAITOK | M_ZERO);
if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
(ef->nrel != 0 && ef->reltab == NULL) ||
(ef->nrela != 0 && ef->relatab == NULL)) {
error = ENOMEM;
goto out;
}
/* XXX, relocate the sh_addr fields saved by the loader. */
off = 0;
for (i = 0; i < hdr->e_shnum; i++) {
if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
off = shdr[i].sh_addr;
}
for (i = 0; i < hdr->e_shnum; i++) {
if (shdr[i].sh_addr != 0)
shdr[i].sh_addr = shdr[i].sh_addr - off +
(Elf_Addr)ef->address;
}
ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
ef->ddbstrcnt = shdr[symstrindex].sh_size;
ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
ef->shstrcnt = shdr[shstrindex].sh_size;
ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
/* Now fill out progtab and the relocation tables. */
pb = 0;
rl = 0;
ra = 0;
for (i = 0; i < hdr->e_shnum; i++) {
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
if (shdr[i].sh_type == SHT_PROGBITS)
ef->progtab[pb].name = "<<PROGBITS>>";
else
ef->progtab[pb].name = "<<NOBITS>>";
ef->progtab[pb].size = shdr[i].sh_size;
ef->progtab[pb].sec = i;
if (ef->shstrtab && shdr[i].sh_name != 0)
ef->progtab[pb].name =
ef->shstrtab + shdr[i].sh_name;
/* Update all symbol values with the offset. */
for (j = 0; j < ef->ddbsymcnt; j++) {
es = &ef->ddbsymtab[j];
if (es->st_shndx != i)
continue;
es->st_value += (Elf_Addr)ef->progtab[pb].addr;
}
pb++;
break;
case SHT_REL:
ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
ef->reltab[rl].sec = shdr[i].sh_info;
rl++;
break;
case SHT_RELA:
ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
ef->relatab[ra].nrela =
shdr[i].sh_size / sizeof(Elf_Rela);
ef->relatab[ra].sec = shdr[i].sh_info;
ra++;
break;
}
}
if (pb != ef->nprogtab)
panic("lost progbits");
if (rl != ef->nrel)
panic("lost rel");
if (ra != ef->nrela)
panic("lost rela");
/* Local intra-module relocations */
link_elf_reloc_local(lf);
*result = lf;
return (0);
out:
/* preload not done this way */
linker_file_unload(lf, LINKER_UNLOAD_FORCE);
return (error);
}
static int
link_elf_link_preload_finish(linker_file_t lf)
{
elf_file_t ef;
int error;
ef = (elf_file_t)lf;
error = relocate_file(ef);
if (error)
return error;
/* Notify MD code that a module is being loaded. */
error = elf_cpu_load_file(lf);
if (error)
return (error);
return (0);
}
static int
link_elf_load_file(linker_class_t cls, const char *filename,
linker_file_t *result)
{
struct nameidata nd;
struct thread *td = curthread; /* XXX */
Elf_Ehdr *hdr;
Elf_Shdr *shdr;
Elf_Sym *es;
int nbytes, i, j;
vm_offset_t mapbase;
size_t mapsize;
int error = 0;
int resid, flags;
elf_file_t ef;
linker_file_t lf;
int symtabindex;
int symstrindex;
int shstrindex;
int nsym;
int pb, rl, ra;
int alignmask;
GIANT_REQUIRED;
shdr = NULL;
lf = NULL;
mapsize = 0;
hdr = NULL;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
flags = FREAD;
error = vn_open(&nd, &flags, 0, -1);
if (error)
return error;
NDFREE(&nd, NDF_ONLY_PNBUF);
#ifdef MAC
error = mac_check_kld_load(td->td_ucred, nd.ni_vp);
if (error) {
goto out;
}
#endif
1998-09-11 08:46:15 +00:00
/* Read the elf header from the file. */
hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
if (hdr == NULL) {
error = ENOMEM;
goto out;
}
error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)hdr, sizeof(*hdr), 0,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error)
goto out;
if (resid != 0){
error = ENOEXEC;
goto out;
}
if (!IS_ELF(*hdr)) {
error = ENOEXEC;
goto out;
}
if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
|| hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
link_elf_error("Unsupported file layout");
error = ENOEXEC;
goto out;
}
if (hdr->e_ident[EI_VERSION] != EV_CURRENT
|| hdr->e_version != EV_CURRENT) {
link_elf_error("Unsupported file version");
error = ENOEXEC;
goto out;
}
if (hdr->e_type != ET_REL) {
link_elf_error("Unsupported file type");
error = ENOEXEC;
goto out;
}
if (hdr->e_machine != ELF_TARG_MACH) {
link_elf_error("Unsupported machine");
error = ENOEXEC;
goto out;
}
First round implementation of a fine grain enhanced module to module version dependency system. This isn't quite finished, but it is at a useful stage to do a functional checkpoint. Highlights: - version and dependency metadata is gathered via linker sets, so things are handled the same for static kernels and code built to live in a kld. - The dependencies are at module level (versus at file level). - Dependencies determine kld symbol search order - this means that you cannot link against symbols in another file unless you depend on it. This is so that you cannot accidently unload the target out from underneath the ones referencing it. - It is flexible enough that we can put tags in #include files and macros so that we can get decent hooks for enforcing recompiles on incompatable ABI changes. eg: if we change struct proc, we could force a recompile for all kld's that reference the proc struct. - Tangled dependency references at boot time are sorted. Files are relocated once all their dependencies are already relocated. Caveats: - Loader support is incomplete, but has been worked on seperately. - Actual enforcement of the version number tags is not active yet - just the module dependencies are live. The actual structure of versioning hasn't been agreed on yet. (eg: major.minor, or whatever) - There is some backwards compatability for old modules without metadata but I'm not sure how good it is. This is based on work originally done by Boris Popov (bp@freebsd.org), but I'm not sure he'd recognize much of it now. Don't blame him. :-) Also, ideas have been borrowed from Mike Smith.
2000-04-29 13:19:31 +00:00
lf = linker_make_file(filename, &link_elf_class);
if (!lf) {
error = ENOMEM;
goto out;
}
ef = (elf_file_t) lf;
ef->nprogtab = 0;
ef->e_shdr = 0;
ef->nrel = 0;
ef->nrela = 0;
/* Allocate and read in the section header */
nbytes = hdr->e_shnum * hdr->e_shentsize;
if (nbytes == 0 || hdr->e_shoff == 0 ||
hdr->e_shentsize != sizeof(Elf_Shdr)) {
error = ENOEXEC;
goto out;
}
shdr = malloc(nbytes, M_LINKER, M_WAITOK);
if (shdr == NULL) {
error = ENOMEM;
goto out;
}
ef->e_shdr = shdr;
error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, hdr->e_shoff,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td);
First round implementation of a fine grain enhanced module to module version dependency system. This isn't quite finished, but it is at a useful stage to do a functional checkpoint. Highlights: - version and dependency metadata is gathered via linker sets, so things are handled the same for static kernels and code built to live in a kld. - The dependencies are at module level (versus at file level). - Dependencies determine kld symbol search order - this means that you cannot link against symbols in another file unless you depend on it. This is so that you cannot accidently unload the target out from underneath the ones referencing it. - It is flexible enough that we can put tags in #include files and macros so that we can get decent hooks for enforcing recompiles on incompatable ABI changes. eg: if we change struct proc, we could force a recompile for all kld's that reference the proc struct. - Tangled dependency references at boot time are sorted. Files are relocated once all their dependencies are already relocated. Caveats: - Loader support is incomplete, but has been worked on seperately. - Actual enforcement of the version number tags is not active yet - just the module dependencies are live. The actual structure of versioning hasn't been agreed on yet. (eg: major.minor, or whatever) - There is some backwards compatability for old modules without metadata but I'm not sure how good it is. This is based on work originally done by Boris Popov (bp@freebsd.org), but I'm not sure he'd recognize much of it now. Don't blame him. :-) Also, ideas have been borrowed from Mike Smith.
2000-04-29 13:19:31 +00:00
if (error)
goto out;
if (resid) {
error = ENOEXEC;
goto out;
}
/* Scan the section header for information and table sizing. */
nsym = 0;
symtabindex = -1;
symstrindex = -1;
for (i = 0; i < hdr->e_shnum; i++) {
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
ef->nprogtab++;
break;
case SHT_SYMTAB:
nsym++;
symtabindex = i;
symstrindex = shdr[i].sh_link;
break;
case SHT_REL:
ef->nrel++;
break;
case SHT_RELA:
ef->nrela++;
break;
case SHT_STRTAB:
break;
}
}
if (ef->nprogtab == 0) {
link_elf_error("file has no contents");
error = ENOEXEC;
goto out;
}
if (nsym != 1) {
/* Only allow one symbol table for now */
link_elf_error("file has no valid symbol table");
error = ENOEXEC;
goto out;
}
if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
shdr[symstrindex].sh_type != SHT_STRTAB) {
link_elf_error("file has invalid symbol strings");
error = ENOEXEC;
goto out;
}
/* Allocate space for tracking the load chunks */
if (ef->nprogtab != 0)
ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
M_LINKER, M_WAITOK | M_ZERO);
if (ef->nrel != 0)
ef->reltab = malloc(ef->nrel * sizeof(*ef->reltab), M_LINKER,
M_WAITOK | M_ZERO);
if (ef->nrela != 0)
ef->relatab = malloc(ef->nrela * sizeof(*ef->relatab), M_LINKER,
M_WAITOK | M_ZERO);
if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
(ef->nrel != 0 && ef->reltab == NULL) ||
(ef->nrela != 0 && ef->relatab == NULL)) {
error = ENOMEM;
goto out;
}
if (symtabindex == -1)
panic("lost symbol table index");
/* Allocate space for and load the symbol table */
ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
if (ef->ddbsymtab == NULL) {
error = ENOMEM;
goto out;
}
error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)ef->ddbsymtab,
shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error)
goto out;
if (resid != 0){
error = EINVAL;
goto out;
}
if (symstrindex == -1)
panic("lost symbol string index");
/* Allocate space for and load the symbol strings */
ef->ddbstrcnt = shdr[symstrindex].sh_size;
ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
if (ef->ddbstrtab == NULL) {
error = ENOMEM;
goto out;
}
error = vn_rdwr(UIO_READ, nd.ni_vp, ef->ddbstrtab,
shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error)
goto out;
if (resid != 0){
error = EINVAL;
goto out;
}
/* Do we have a string table for the section names? */
shstrindex = -1;
if (hdr->e_shstrndx != 0 &&
shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
shstrindex = hdr->e_shstrndx;
ef->shstrcnt = shdr[shstrindex].sh_size;
ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
M_WAITOK);
if (ef->shstrtab == NULL) {
error = ENOMEM;
goto out;
}
error = vn_rdwr(UIO_READ, nd.ni_vp, ef->shstrtab,
shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
In order to better support flexible and extensible access control, make a series of modifications to the credential arguments relating to file read and write operations to cliarfy which credential is used for what: - Change fo_read() and fo_write() to accept "active_cred" instead of "cred", and change the semantics of consumers of fo_read() and fo_write() to pass the active credential of the thread requesting an operation rather than the cached file cred. The cached file cred is still available in fo_read() and fo_write() consumers via fp->f_cred. These changes largely in sys_generic.c. For each implementation of fo_read() and fo_write(), update cred usage to reflect this change and maintain current semantics: - badfo_readwrite() unchanged - kqueue_read/write() unchanged pipe_read/write() now authorize MAC using active_cred rather than td->td_ucred - soo_read/write() unchanged - vn_read/write() now authorize MAC using active_cred but VOP_READ/WRITE() with fp->f_cred Modify vn_rdwr() to accept two credential arguments instead of a single credential: active_cred and file_cred. Use active_cred for MAC authorization, and select a credential for use in VOP_READ/WRITE() based on whether file_cred is NULL or not. If file_cred is provided, authorize the VOP using that cred, otherwise the active credential, matching current semantics. Modify current vn_rdwr() consumers to pass a file_cred if used in the context of a struct file, and to always pass active_cred. When vn_rdwr() is used without a file_cred, pass NOCRED. These changes should maintain current semantics for read/write, but avoid a redundant passing of fp->f_cred, as well as making it more clear what the origin of each credential is in file descriptor read/write operations. Follow-up commits will make similar changes to other file descriptor operations, and modify the MAC framework to pass both credentials to MAC policy modules so they can implement either semantic for revocation. Obtained from: TrustedBSD Project Sponsored by: DARPA, NAI Labs
2002-08-15 20:55:08 +00:00
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error)
goto out;
if (resid != 0){
error = EINVAL;
goto out;
}
1998-09-11 08:46:15 +00:00
}
/* Size up code/data(progbits) and bss(nobits). */
alignmask = 0;
for (i = 0; i < hdr->e_shnum; i++) {
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
alignmask = shdr[i].sh_addralign - 1;
mapsize += alignmask;
mapsize &= ~alignmask;
mapsize += shdr[i].sh_size;
break;
}
1998-09-11 08:46:15 +00:00
}
/*
* We know how much space we need for the text/data/bss/etc.
* This stuff needs to be in a single chunk so that profiling etc
* can get the bounds and gdb can associate offsets with modules
1998-09-11 08:46:15 +00:00
*/
ef->object = vm_object_allocate(OBJT_DEFAULT,
round_page(mapsize) >> PAGE_SHIFT);
if (ef->object == NULL) {
error = ENOMEM;
goto out;
}
vm_object_reference(ef->object);
ef->address = (caddr_t) vm_map_min(kernel_map);
error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
round_page(mapsize), TRUE, VM_PROT_ALL, VM_PROT_ALL, FALSE);
if (error) {
vm_object_deallocate(ef->object);
ef->object = 0;
goto out;
}
/* Wire the pages */
vm_map_wire(kernel_map, mapbase,
mapbase + round_page(mapsize),
VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
/* Inform the kld system about the situation */
lf->address = ef->address = (caddr_t)mapbase;
lf->size = mapsize;
/*
* Now load code/data(progbits), zero bss(nobits), allocate space for
* and load relocs
*/
pb = 0;
rl = 0;
ra = 0;
alignmask = 0;
for (i = 0; i < hdr->e_shnum; i++) {
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
alignmask = shdr[i].sh_addralign - 1;
mapbase += alignmask;
mapbase &= ~alignmask;
ef->progtab[pb].addr = (void *)(uintptr_t)mapbase;
if (shdr[i].sh_type == SHT_PROGBITS) {
ef->progtab[pb].name = "<<PROGBITS>>";
error = vn_rdwr(UIO_READ, nd.ni_vp,
ef->progtab[pb].addr,
shdr[i].sh_size, shdr[i].sh_offset,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
NOCRED, &resid, td);
if (error)
goto out;
if (resid != 0){
error = EINVAL;
goto out;
}
} else {
ef->progtab[pb].name = "<<NOBITS>>";
bzero(ef->progtab[pb].addr, shdr[i].sh_size);
}
ef->progtab[pb].size = shdr[i].sh_size;
ef->progtab[pb].sec = i;
if (ef->shstrtab && shdr[i].sh_name != 0)
ef->progtab[pb].name =
ef->shstrtab + shdr[i].sh_name;
/* Update all symbol values with the offset. */
for (j = 0; j < ef->ddbsymcnt; j++) {
es = &ef->ddbsymtab[j];
if (es->st_shndx != i)
continue;
es->st_value += (Elf_Addr)ef->progtab[pb].addr;
}
mapbase += shdr[i].sh_size;
pb++;
break;
case SHT_REL:
ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
M_WAITOK);
ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
ef->reltab[rl].sec = shdr[i].sh_info;
error = vn_rdwr(UIO_READ, nd.ni_vp,
(void *)ef->reltab[rl].rel,
shdr[i].sh_size, shdr[i].sh_offset,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error)
goto out;
if (resid != 0){
error = EINVAL;
goto out;
}
rl++;
break;
case SHT_RELA:
ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
M_WAITOK);
ef->relatab[ra].nrela =
shdr[i].sh_size / sizeof(Elf_Rela);
ef->relatab[ra].sec = shdr[i].sh_info;
error = vn_rdwr(UIO_READ, nd.ni_vp,
(void *)ef->relatab[ra].rela,
shdr[i].sh_size, shdr[i].sh_offset,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error)
goto out;
if (resid != 0){
error = EINVAL;
goto out;
}
ra++;
break;
}
}
if (pb != ef->nprogtab)
panic("lost progbits");
if (rl != ef->nrel)
panic("lost rel");
if (ra != ef->nrela)
panic("lost rela");
if (mapbase != (vm_offset_t)ef->address + mapsize)
2004-06-29 03:13:54 +00:00
panic("mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
mapbase, ef->address, mapsize,
(vm_offset_t)ef->address + mapsize);
/* Local intra-module relocations */
link_elf_reloc_local(lf);
/* Pull in dependencies */
error = linker_load_dependencies(lf);
if (error)
goto out;
/* External relocations */
error = relocate_file(ef);
if (error)
goto out;
/* Notify MD code that a module is being loaded. */
error = elf_cpu_load_file(lf);
if (error)
goto out;
*result = lf;
out:
if (error && lf)
linker_file_unload(lf, LINKER_UNLOAD_FORCE);
if (hdr)
free(hdr, M_LINKER);
VOP_UNLOCK(nd.ni_vp, 0, td);
vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
return error;
}
static void
link_elf_unload_file(linker_file_t file)
{
elf_file_t ef = (elf_file_t) file;
int i;
/* Notify MD code that a module is being unloaded. */
elf_cpu_unload_file(file);
if (ef->preloaded) {
if (ef->reltab)
free(ef->reltab, M_LINKER);
if (ef->relatab)
free(ef->relatab, M_LINKER);
if (ef->progtab)
free(ef->progtab, M_LINKER);
if (file->filename != NULL)
preload_delete_name(file->filename);
/* XXX reclaim module memory? */
return;
}
for (i = 0; i < ef->nrel; i++)
if (ef->reltab[i].rel)
free(ef->reltab[i].rel, M_LINKER);
for (i = 0; i < ef->nrela; i++)
if (ef->relatab[i].rela)
free(ef->relatab[i].rela, M_LINKER);
if (ef->reltab)
free(ef->reltab, M_LINKER);
if (ef->relatab)
free(ef->relatab, M_LINKER);
if (ef->progtab)
free(ef->progtab, M_LINKER);
if (ef->object) {
vm_map_remove(kernel_map, (vm_offset_t) ef->address,
(vm_offset_t) ef->address +
(ef->object->size << PAGE_SHIFT));
vm_object_deallocate(ef->object);
}
if (ef->e_shdr)
free(ef->e_shdr, M_LINKER);
if (ef->ddbsymtab)
free(ef->ddbsymtab, M_LINKER);
if (ef->ddbstrtab)
free(ef->ddbstrtab, M_LINKER);
if (ef->shstrtab)
free(ef->shstrtab, M_LINKER);
}
1998-09-11 08:46:15 +00:00
static const char *
symbol_name(elf_file_t ef, Elf_Word r_info)
{
const Elf_Sym *ref;
if (ELF_R_SYM(r_info)) {
ref = ef->ddbsymtab + ELF_R_SYM(r_info);
return ef->ddbstrtab + ref->st_name;
} else
return NULL;
}
static Elf_Addr
findbase(elf_file_t ef, int sec)
{
int i;
Elf_Addr base = 0;
for (i = 0; i < ef->nprogtab; i++) {
if (sec == ef->progtab[i].sec) {
base = (Elf_Addr)ef->progtab[i].addr;
break;
}
}
return base;
}
static int
relocate_file(elf_file_t ef)
{
const Elf_Rel *rellim;
const Elf_Rel *rel;
const Elf_Rela *relalim;
const Elf_Rela *rela;
const char *symname;
const Elf_Sym *sym;
int i;
Elf_Word symidx;
Elf_Addr base;
/* Perform relocations without addend if there are any: */
for (i = 0; i < ef->nrel; i++) {
rel = ef->reltab[i].rel;
if (rel == NULL)
panic("lost a reltab!");
rellim = rel + ef->reltab[i].nrel;
base = findbase(ef, ef->reltab[i].sec);
if (base == 0)
panic("lost base for reltab");
for ( ; rel < rellim; rel++) {
symidx = ELF_R_SYM(rel->r_info);
if (symidx >= ef->ddbsymcnt)
continue;
sym = ef->ddbsymtab + symidx;
/* Local relocs are already done */
if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
continue;
if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
elf_obj_lookup)) {
symname = symbol_name(ef, rel->r_info);
printf("link_elf_obj: symbol %s undefined\n",
symname);
return ENOENT;
}
}
1998-09-11 08:46:15 +00:00
}
/* Perform relocations with addend if there are any: */
for (i = 0; i < ef->nrela; i++) {
rela = ef->relatab[i].rela;
if (rela == NULL)
panic("lost a relatab!");
relalim = rela + ef->relatab[i].nrela;
base = findbase(ef, ef->relatab[i].sec);
if (base == 0)
panic("lost base for relatab");
for ( ; rela < relalim; rela++) {
symidx = ELF_R_SYM(rela->r_info);
if (symidx >= ef->ddbsymcnt)
continue;
sym = ef->ddbsymtab + symidx;
/* Local relocs are already done */
if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
continue;
if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
elf_obj_lookup)) {
symname = symbol_name(ef, rela->r_info);
printf("link_elf_obj: symbol %s undefined\n",
symname);
return ENOENT;
}
}
1998-09-11 08:46:15 +00:00
}
return 0;
}
1998-09-11 08:46:15 +00:00
static int
link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
{
elf_file_t ef = (elf_file_t) lf;
const Elf_Sym *symp;
const char *strp;
int i;
for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
strp = ef->ddbstrtab + symp->st_name;
if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
*sym = (c_linker_sym_t) symp;
return 0;
}
}
return ENOENT;
}
static int
link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
linker_symval_t *symval)
{
elf_file_t ef = (elf_file_t) lf;
const Elf_Sym *es = (const Elf_Sym*) sym;
if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
symval->name = ef->ddbstrtab + es->st_name;
symval->value = (caddr_t)es->st_value;
symval->size = es->st_size;
return 0;
}
return ENOENT;
}
static int
link_elf_search_symbol(linker_file_t lf, caddr_t value,
c_linker_sym_t *sym, long *diffp)
{
elf_file_t ef = (elf_file_t) lf;
u_long off = (uintptr_t) (void *) value;
u_long diff = off;
u_long st_value;
const Elf_Sym *es;
const Elf_Sym *best = 0;
int i;
for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
if (es->st_name == 0)
continue;
st_value = es->st_value;
if (off >= st_value) {
if (off - st_value < diff) {
diff = off - st_value;
best = es;
if (diff == 0)
break;
} else if (off - st_value == diff) {
best = es;
}
}
}
if (best == 0)
*diffp = off;
else
*diffp = diff;
*sym = (c_linker_sym_t) best;
return 0;
}
/*
* Look up a linker set on an ELF system.
*/
static int
link_elf_lookup_set(linker_file_t lf, const char *name,
void ***startp, void ***stopp, int *countp)
{
elf_file_t ef = (elf_file_t)lf;
void **start, **stop;
int i, count;
/* Relative to section number */
for (i = 0; i < ef->nprogtab; i++) {
if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
strcmp(ef->progtab[i].name + 4, name) == 0) {
start = (void **)ef->progtab[i].addr;
stop = (void **)((char *)ef->progtab[i].addr +
ef->progtab[i].size);
count = stop - start;
if (startp)
*startp = start;
if (stopp)
*stopp = stop;
if (countp)
*countp = count;
return (0);
}
}
return (ESRCH);
}
static int
link_elf_each_function_name(linker_file_t file,
int (*callback)(const char *, void *), void *opaque)
{
elf_file_t ef = (elf_file_t)file;
const Elf_Sym *symp;
int i, error;
/* Exhaustive search */
for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
if (symp->st_value != 0 &&
ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
error = callback(ef->ddbstrtab + symp->st_name, opaque);
if (error)
return (error);
}
}
return (0);
}
/*
* Symbol lookup function that can be used when the symbol index is known (ie
* in relocations). It uses the symbol index instead of doing a fully fledged
* hash table based lookup when such is valid. For example for local symbols.
* This is not only more efficient, it's also more correct. It's not always
* the case that the symbol can be found through the hash table.
*/
static Elf_Addr
elf_obj_lookup(linker_file_t lf, Elf_Word symidx, int deps)
{
elf_file_t ef = (elf_file_t)lf;
const Elf_Sym *sym;
const char *symbol;
Elf_Addr ret;
/* Don't even try to lookup the symbol if the index is bogus. */
if (symidx >= ef->ddbsymcnt)
return (0);
sym = ef->ddbsymtab + symidx;
/* Quick answer if there is a definition included. */
if (sym->st_shndx != SHN_UNDEF)
return (sym->st_value);
/* If we get here, then it is undefined and needs a lookup. */
switch (ELF_ST_BIND(sym->st_info)) {
case STB_LOCAL:
/* Local, but undefined? huh? */
return (0);
case STB_GLOBAL:
/* Relative to Data or Function name */
symbol = ef->ddbstrtab + sym->st_name;
/* Force a lookup failure if the symbol name is bogus. */
if (*symbol == 0)
return (0);
ret = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
return ret;
case STB_WEAK:
printf("link_elf_obj: Weak symbols not supported\n");
return (0);
default:
return (0);
}
}
static void
link_elf_reloc_local(linker_file_t lf)
{
elf_file_t ef = (elf_file_t)lf;
const Elf_Rel *rellim;
const Elf_Rel *rel;
const Elf_Rela *relalim;
const Elf_Rela *rela;
const Elf_Sym *sym;
Elf_Addr base;
int i;
Elf_Word symidx;
/* Perform relocations without addend if there are any: */
for (i = 0; i < ef->nrel; i++) {
rel = ef->reltab[i].rel;
if (rel == NULL)
panic("lost a reltab!");
rellim = rel + ef->reltab[i].nrel;
base = findbase(ef, ef->reltab[i].sec);
if (base == 0)
panic("lost base for reltab");
for ( ; rel < rellim; rel++) {
symidx = ELF_R_SYM(rel->r_info);
if (symidx >= ef->ddbsymcnt)
continue;
sym = ef->ddbsymtab + symidx;
/* Only do local relocs */
if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
continue;
elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
elf_obj_lookup);
}
}
/* Perform relocations with addend if there are any: */
for (i = 0; i < ef->nrela; i++) {
rela = ef->relatab[i].rela;
if (rela == NULL)
panic("lost a relatab!");
relalim = rela + ef->relatab[i].nrela;
base = findbase(ef, ef->relatab[i].sec);
if (base == 0)
panic("lost base for relatab");
for ( ; rela < relalim; rela++) {
symidx = ELF_R_SYM(rela->r_info);
if (symidx >= ef->ddbsymcnt)
continue;
sym = ef->ddbsymtab + symidx;
/* Only do local relocs */
if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
continue;
elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
elf_obj_lookup);
}
}
}