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Keep shadow copies of the e_shnum', e_phnum' and `e_shstrndx'

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members of the ELF Executable Header inside the library-private
`struct _Elf' descriptor and only update the underlying Elf{32,64}_Ehdr
structure on an elf_update(3) call.  These fields of the Ehdr
structure are technically `out of bounds' for an application program
per the ELF(3) API, but we've seen applications that initialize
a new Ehdr structure using memcpy(), messing up the library's
invariants. [1]

Implement elf_getphnum() and handle ELF objects with more than
64K program header table entries.

Reported by:	jb [1]
This commit is contained in:
Joseph Koshy 2006-12-25 02:22:22 +00:00
parent a2dc08f2b8
commit f6c0f35e07
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=165535
13 changed files with 433 additions and 220 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
lib/libelf/Makefile
View File

@ -18,6 +18,7 @@ SRCS= elf_begin.c \
elf_next.c \
elf_rand.c \
elf_rawfile.c \
elf_phnum.c \
elf_shnum.c \
elf_shstrndx.c \
elf_scn.c \
@ -46,6 +47,7 @@ SRCS= elf_begin.c \
libelf_checksum.c \
libelf_data.c \
libelf_ehdr.c \
libelf_extended.c \
libelf_phdr.c \
libelf_shdr.c \
libelf_xlate.c \
@ -72,6 +74,7 @@ MAN= elf.3 \
elf_getdata.3 \
elf_getident.3 \
elf_getscn.3 \
elf_getphnum.3 \
elf_getshnum.3 \
elf_getshstrndx.3 \
elf_hash.3 \

1
lib/libelf/Version.map
View File

@ -39,6 +39,7 @@ global:
elf_getdata;
elf_getident;
elf_getscn;
elf_getphnum;
elf_getshnum;
elf_getshstrndx;
elf_hash;

8
lib/libelf/_libelf.h
View File

@ -71,6 +71,7 @@ extern struct _libelf_globals _libelf;
*/
#define LIBELF_F_MALLOCED 0x010000 /* whether data was malloc'ed */
#define LIBELF_F_MMAP 0x020000 /* whether e_rawfile was mmap'ed */
#define LIBELF_F_SHDRS_LOADED 0x040000 /* whether all shdrs were read in */
struct _Elf {
int e_activations; /* activation count */
@ -107,6 +108,9 @@ struct _Elf {
Elf64_Phdr *e_phdr64;
} e_phdr;
STAILQ_HEAD(, _Elf_Scn) e_scn; /* section list */
size_t e_nphdr; /* number of Phdr entries */
size_t e_nscn; /* number of sections */
size_t e_strndx; /* string table section index */
} e_elf;
} e_u;
};
@ -171,9 +175,6 @@ void (*_libelf_get_translator(Elf_Type _t, int _direction, int _elfclass))
(char *_dst, char *_src, size_t _cnt, int _byteswap);
void *_libelf_getphdr(Elf *_e, int _elfclass);
void *_libelf_getshdr(Elf_Scn *_scn, int _elfclass);
int _libelf_getshnum(Elf *_e, void *_eh, int _elfclass, size_t *_shnum);
int _libelf_getshstrndx(Elf *_e, void *_eh, int _elfclass,
size_t *_shstrndx);
void _libelf_init_elf(Elf *_e, Elf_Kind _kind);
int _libelf_malign(Elf_Type _t, int _elfclass);
size_t _libelf_msize(Elf_Type _t, int _elfclass, unsigned int _version);
@ -181,6 +182,7 @@ void *_libelf_newphdr(Elf *_e, int _elfclass, size_t _count);
Elf_Data *_libelf_release_data(Elf_Data *_d);
Elf *_libelf_release_elf(Elf *_e);
Elf_Scn *_libelf_release_scn(Elf_Scn *_s);
int _libelf_setphnum(Elf *_e, void *_eh, int _elfclass, size_t _phnum);
int _libelf_setshnum(Elf *_e, void *_eh, int _elfclass, size_t _shnum);
int _libelf_setshstrndx(Elf *_e, void *_eh, int _elfclass,
size_t _shstrndx);

87
lib/libelf/elf_getphnum.3 Normal file
View File

@ -0,0 +1,87 @@
.\" Copyright (c) 2006 Joseph Koshy. 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 Joseph Koshy ``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 Joseph Koshy 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.
.\"
.\" $FreeBSD$
.\"
.Dd December 16, 2006
.Os
.Dt ELF_GETPHNUM 3
.Sh NAME
.Nm elf_getphnum
.Nd return the number of program headers in an ELF file
.Sh LIBRARY
.Lb libelf
.Sh SYNOPSIS
.In libelf.h
.Ft int
.Fn elf_getphnum "Elf *elf" "size_t *phnum"
.Sh DESCRIPTION
Function
.Fn elf_getphnum
retrieves the number of ELF program headers associated with descriptor
.Ar elf
and stores it into the location pointed to by argument
.Ar phnum .
.Pp
This routine allows applications to uniformly process both normal ELF
objects and ELF objects that use extended numbering.
.Pp
.Sh RETURN VALUES
Function
.Fn elf_getphnum
returns a non-zero value if successful, or zero in case of an
error.
.Sh ERRORS
Function
.Fn elf_getphnum
can fail with the following errors:
.Bl -tag -width "[ELF_E_RESOURCE]"
.It Bq Er ELF_E_ARGUMENT
A NULL value was passed in for argument
.Ar elf .
.It Bq Er ELF_E_ARGUMENT
Argument
.Ar elf
was not for an ELF file.
.It Bq Er ELF_E_ARGUMENT
Argument
.Ar elf
lacks an ELF Executable Header.
.It Bq Er ELF_E_HEADER
The ELF Executable Header associated with argument
.Ar elf
was corrupt.
.It Bq Er ELF_E_SECTION
The section header at index
.Dv SHN_UNDEF
was corrupt.
.El
.Sh SEE ALSO
.Xr elf 3 ,
.Xr elf32_getehdr 3 ,
.Xr elf64_getehdr 3 ,
.Xr elf_getident 3 ,
.Xr elf_getshnum 3 ,
.Xr elf_getshstrndx 3 ,
.Xr gelf 3 ,
.Xr gelf_getehdr 3

53
lib/libelf/elf_phnum.c Normal file
View File

@ -0,0 +1,53 @@
/*-
* Copyright (c) 2006 Joseph Koshy
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <ar.h>
#include <libelf.h>
#include "_libelf.h"
int
elf_getphnum(Elf *e, size_t *phnum)
{
void *eh;
int ec;
if (e == NULL || e->e_kind != ELF_K_ELF ||
((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64)) {
LIBELF_SET_ERROR(ARGUMENT, 0);
return (0);
}
if ((eh = _libelf_ehdr(e, ec, 0)) == NULL)
return (0);
*phnum = e->e_u.e_elf.e_nphdr;
return (1);
}

70
lib/libelf/elf_scn.c
View File

@ -44,7 +44,6 @@ _libelf_load_scn(Elf *e, void *ehdr)
int ec, swapbytes;
size_t fsz, i, shnum;
uint64_t shoff;
uint32_t shtype;
char *src;
Elf32_Ehdr *eh32;
Elf64_Ehdr *eh64;
@ -53,6 +52,7 @@ _libelf_load_scn(Elf *e, void *ehdr)
assert(e != NULL);
assert(ehdr != NULL);
assert((e->e_flags & LIBELF_F_SHDRS_LOADED) == 0);
#define CHECK_EHDR(E,EH) do { \
if (fsz != (EH)->e_shentsize || \
@ -62,18 +62,18 @@ _libelf_load_scn(Elf *e, void *ehdr)
} \
} while (0)
fsz = gelf_fsize(e, ELF_T_SHDR, (size_t) 1, e->e_version);
ec = e->e_class;
fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1);
assert(fsz > 0);
ec = e->e_class;
shnum = e->e_u.e_elf.e_nscn;
if (ec == ELFCLASS32) {
eh32 = (Elf32_Ehdr *) ehdr;
shnum = eh32->e_shnum;
shoff = (uint64_t) eh32->e_shoff;
CHECK_EHDR(e, eh32);
} else {
eh64 = (Elf64_Ehdr *) ehdr;
shnum = eh64->e_shnum;
shoff = eh64->e_shoff;
CHECK_EHDR(e, eh64);
}
@ -82,32 +82,18 @@ _libelf_load_scn(Elf *e, void *ehdr)
swapbytes = e->e_byteorder != LIBELF_PRIVATE(byteorder);
src = e->e_rawfile + shoff;
/*
* If the file is using extended numbering then section #0
* would have already been read in.
*/
i = 0;
if (!STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) {
assert(STAILQ_FIRST(&e->e_u.e_elf.e_scn) ==
STAILQ_LAST(&e->e_u.e_elf.e_scn, _Elf_Scn, s_next));
if (shnum == (size_t) 0 && shoff != 0LL) {
/* Extended section numbering */
if ((scn = _libelf_allocate_scn(e, (size_t) 0)) == NULL)
return (0);
(*xlator)((char *) &scn->s_shdr, src, (size_t) 1, swapbytes);
if (ec == ELFCLASS32) {
shtype = scn->s_shdr.s_shdr32.sh_type;
shnum = scn->s_shdr.s_shdr32.sh_size;
} else {
shtype = scn->s_shdr.s_shdr64.sh_type;
shnum = scn->s_shdr.s_shdr64.sh_size;
}
if (shtype != SHT_NULL) {
LIBELF_SET_ERROR(SECTION, 0);
return (0);
}
scn->s_size = 0LL;
scn->s_offset = scn->s_rawoff = 0LL;
i++;
i = 1;
src += fsz;
}
@ -127,6 +113,9 @@ _libelf_load_scn(Elf *e, void *ehdr)
scn->s_size = scn->s_shdr.s_shdr64.sh_size;
}
}
e->e_flags |= LIBELF_F_SHDRS_LOADED;
return (1);
}
@ -147,7 +136,8 @@ elf_getscn(Elf *e, size_t index)
if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
return (NULL);
if (e->e_cmd != ELF_C_WRITE && STAILQ_EMPTY(&e->e_u.e_elf.e_scn) &&
if (e->e_cmd != ELF_C_WRITE &&
(e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 &&
_libelf_load_scn(e, ehdr) == 0)
return (NULL);
@ -174,7 +164,6 @@ elf_newscn(Elf *e)
{
int ec;
void *ehdr;
size_t shnum;
Elf_Scn *scn;
if (e == NULL || e->e_kind != ELF_K_ELF) {
@ -200,30 +189,25 @@ elf_newscn(Elf *e)
* file using ELF_C_READ, mess with its internal structure and
* use elf_update(...,ELF_C_NULL) to compute its new layout.
*/
if (e->e_cmd != ELF_C_WRITE && STAILQ_EMPTY(&e->e_u.e_elf.e_scn) &&
if (e->e_cmd != ELF_C_WRITE &&
(e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 &&
_libelf_load_scn(e, ehdr) == 0)
return (NULL);
if (_libelf_getshnum(e, ehdr, ec, &shnum) == 0)
return (NULL);
if (STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) {
assert(shnum == 0);
assert(e->e_u.e_elf.e_nscn == 0);
if ((scn = _libelf_allocate_scn(e, (size_t) SHN_UNDEF)) ==
NULL)
return (NULL);
shnum++;
e->e_u.e_elf.e_nscn++;
}
assert(shnum > 0);
assert(e->e_u.e_elf.e_nscn > 0);
if ((scn = _libelf_allocate_scn(e, shnum)) == NULL)
if ((scn = _libelf_allocate_scn(e, e->e_u.e_elf.e_nscn)) == NULL)
return (NULL);
shnum++;
if (_libelf_setshnum(e, ehdr, ec, shnum) == 0)
return (NULL);
e->e_u.e_elf.e_nscn++;
(void) elf_flagscn(scn, ELF_C_SET, ELF_F_DIRTY);

84
lib/libelf/elf_shnum.c
View File

@ -32,80 +32,6 @@ __FBSDID("$FreeBSD$");
#include "_libelf.h"
int
_libelf_getshnum(Elf *e, void *eh, int ec, size_t *shnum)
{
Elf64_Off off;
Elf_Scn *scn;
void *sh;
size_t n;
if (ec == ELFCLASS32) {
n = ((Elf32_Ehdr *) eh)->e_shnum;
off = (Elf64_Off) ((Elf32_Ehdr *) eh)->e_shoff;
} else {
n = ((Elf64_Ehdr *) eh)->e_shnum;
off = ((Elf64_Ehdr *) eh)->e_shoff;
}
if (n != 0) {
*shnum = n;
return (1);
}
if (off == 0L) {
*shnum = (size_t) 0;
return (1);
}
/*
* If 'e_shnum' is zero and 'e_shoff' is non-zero, the file is
* using extended section numbering, and the true section
* number is kept in the 'sh_size' field of the section header
* at offset SHN_UNDEF.
*/
if ((scn = elf_getscn(e, (size_t) SHN_UNDEF)) == NULL)
return (0);
if ((sh = _libelf_getshdr(scn, ec)) == NULL)
return (0);
if (ec == ELFCLASS32)
*shnum = ((Elf32_Shdr *) sh)->sh_size;
else
*shnum = ((Elf64_Shdr *) sh)->sh_size;
return (1);
}
int
_libelf_setshnum(Elf *e, void *eh, int ec, size_t shnum)
{
Elf_Scn *scn;
void *sh;
if (shnum < SHN_LORESERVE) {
if (ec == ELFCLASS32)
((Elf32_Ehdr *) eh)->e_shnum = shnum;
else
((Elf64_Ehdr *) eh)->e_shnum = shnum;
return (1);
}
if ((scn = elf_getscn(e, (size_t) SHN_UNDEF)) == NULL)
return (0);
if ((sh = _libelf_getshdr(scn, ec)) == NULL)
return (0);
if (ec == ELFCLASS32)
((Elf32_Shdr *) sh)->sh_size = shnum;
else
((Elf64_Shdr *) sh)->sh_size = shnum;
(void) elf_flagshdr(scn, ELF_C_SET, ELF_F_DIRTY);
return (1);
}
int
elf_getshnum(Elf *e, size_t *shnum)
{
@ -113,11 +39,15 @@ elf_getshnum(Elf *e, size_t *shnum)
int ec;
if (e == NULL || e->e_kind != ELF_K_ELF ||
((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) ||
((eh = _libelf_ehdr(e, ec, 0)) == NULL)) {
((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64)) {
LIBELF_SET_ERROR(ARGUMENT, 0);
return (0);
}
return (_libelf_getshnum(e, eh, ec, shnum));
if ((eh = _libelf_ehdr(e, ec, 0)) == NULL)
return (0);
*shnum = e->e_u.e_elf.e_nscn;
return (1);
}

72
lib/libelf/elf_shstrndx.c
View File

@ -32,68 +32,6 @@ __FBSDID("$FreeBSD$");
#include "_libelf.h"
/*
* Helpers to get/set the e_shstrndx field of the ELF header.
*/
int
_libelf_getshstrndx(Elf *e, void *eh, int ec, size_t *strndx)
{
Elf_Scn *scn;
void *sh;
size_t n;
n = (ec == ELFCLASS32) ? ((Elf32_Ehdr *) eh)->e_shstrndx :
((Elf64_Ehdr *) eh)->e_shstrndx;
if (n < SHN_LORESERVE) {
*strndx = n;
return (1);
}
if ((scn = elf_getscn(e, (size_t) SHN_UNDEF)) == NULL)
return (0);
if ((sh = _libelf_getshdr(scn, ec)) == NULL)
return (0);
if (ec == ELFCLASS32)
*strndx = ((Elf32_Shdr *) sh)->sh_link;
else
*strndx = ((Elf64_Shdr *) sh)->sh_link;
return (1);
}
int
_libelf_setshstrndx(Elf *e, void *eh, int ec, size_t strndx)
{
Elf_Scn *scn;
void *sh;
if (strndx < SHN_LORESERVE) {
if (ec == ELFCLASS32)
((Elf32_Ehdr *) eh)->e_shstrndx = strndx;
else
((Elf64_Ehdr *) eh)->e_shstrndx = strndx;
return (1);
}
if ((scn = elf_getscn(e, (size_t) SHN_UNDEF)) == NULL)
return (0);
if ((sh = _libelf_getshdr(scn, ec)) == NULL)
return (0);
if (ec == ELFCLASS32) {
((Elf32_Ehdr *) eh)->e_shstrndx = SHN_XINDEX;
((Elf32_Shdr *) sh)->sh_link = strndx;
} else {
((Elf64_Ehdr *) eh)->e_shstrndx = SHN_XINDEX;
((Elf64_Shdr *) sh)->sh_link = strndx;
}
return (1);
}
int
elf_getshstrndx(Elf *e, size_t *strndx)
{
@ -101,13 +39,17 @@ elf_getshstrndx(Elf *e, size_t *strndx)
int ec;
if (e == NULL || e->e_kind != ELF_K_ELF ||
((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) ||
((eh = _libelf_ehdr(e, ec, 0)) == NULL)) {
((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64)) {
LIBELF_SET_ERROR(ARGUMENT, 0);
return (0);
}
return (_libelf_getshstrndx(e, eh, ec, strndx));
if ((eh = _libelf_ehdr(e, ec, 0)) == NULL)
return (0);
*strndx = e->e_u.e_elf.e_strndx;
return (1);
}
int

18
lib/libelf/elf_update.c
View File

@ -346,7 +346,6 @@ _libelf_resync_elf(Elf *e)
if (ec == ELFCLASS32) {
eh_byteorder = eh32->e_ident[EI_DATA];
eh_class = eh32->e_ident[EI_CLASS];
phnum = eh32->e_phnum;
phoff = (uint64_t) eh32->e_phoff;
shoff = (uint64_t) eh32->e_shoff;
eh_type = eh32->e_type;
@ -354,7 +353,6 @@ _libelf_resync_elf(Elf *e)
} else {
eh_byteorder = eh64->e_ident[EI_DATA];
eh_class = eh64->e_ident[EI_CLASS];
phnum = eh64->e_phnum;
phoff = eh64->e_phoff;
shoff = eh64->e_shoff;
eh_type = eh64->e_type;
@ -379,8 +377,8 @@ _libelf_resync_elf(Elf *e)
return ((off_t) -1);
}
if (_libelf_getshnum(e, ehdr, ec, &shnum) == 0)
return ((off_t) -1);
shnum = e->e_u.e_elf.e_nscn;
phnum = e->e_u.e_elf.e_nphdr;
e->e_byteorder = eh_byteorder;
@ -471,6 +469,13 @@ _libelf_resync_elf(Elf *e)
} else
shoff = 0;
/*
* Set the fields of the Executable Header that could potentially use
* extended numbering.
*/
_libelf_setphnum(e, ehdr, ec, phnum);
_libelf_setshnum(e, ehdr, ec, shnum);
/*
* Update the `e_phoff' and `e_shoff' fields if the library is
* doing the layout.
@ -638,18 +643,17 @@ _libelf_write_elf(Elf *e, off_t newsize)
ehdr = _libelf_ehdr(e, ec, 0);
assert(ehdr != NULL);
phnum = e->e_u.e_elf.e_nphdr;
if (ec == ELFCLASS32) {
eh32 = (Elf32_Ehdr *) ehdr;
phnum = eh32->e_phnum;
phoff = (uint64_t) eh32->e_phoff;
shnum = eh32->e_shnum;
shoff = (uint64_t) eh32->e_shoff;
} else {
eh64 = (Elf64_Ehdr *) ehdr;
phnum = eh64->e_phnum;
phoff = eh64->e_phoff;
shnum = eh64->e_shnum;
shoff = eh64->e_shoff;

2
lib/libelf/libelf_checksum.c
View File

@ -76,7 +76,7 @@ _libelf_checksum(Elf *e, int elfclass)
*/
checksum = 0;
for (shn = 1; shn < eh.e_shnum; shn++) {
for (shn = 1; shn < e->e_u.e_elf.e_nscn; shn++) {
if ((scn = elf_getscn(e, shn)) == NULL)
return (0);
if (gelf_getshdr(scn, &shdr) == NULL)

85
lib/libelf/libelf_ehdr.c
View File

@ -36,6 +36,54 @@ __FBSDID("$FreeBSD$");
#include "_libelf.h"
/*
* Retrieve counts for sections, phdrs and the section string table index
* from section header #0 of the ELF object.
*/
static int
_libelf_load_extended(Elf *e, int ec, uint64_t shoff, uint16_t phnum,
uint16_t strndx)
{
Elf_Scn *scn;
size_t fsz;
void (*xlator)(char *_d, char *_s, size_t _c, int _swap);
uint32_t shtype;
assert(STAILQ_EMPTY(&e->e_u.e_elf.e_scn));
fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, 1);
assert(fsz > 0);
if (e->e_rawsize < shoff + fsz) { /* raw file too small */
LIBELF_SET_ERROR(HEADER, 0);
return (0);
}
if ((scn = _libelf_allocate_scn(e, (size_t) 0)) == NULL)
return (0);
xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec);
(*xlator)((char *) &scn->s_shdr, e->e_rawfile + shoff, (size_t) 1,
e->e_byteorder != LIBELF_PRIVATE(byteorder));
#define GET_SHDR_MEMBER(M) ((ec == ELFCLASS32) ? scn->s_shdr.s_shdr32.M : \
scn->s_shdr.s_shdr64.M)
if ((shtype = GET_SHDR_MEMBER(sh_type)) != SHT_NULL) {
LIBELF_SET_ERROR(SECTION, 0);
return (0);
}
e->e_u.e_elf.e_nscn = GET_SHDR_MEMBER(sh_size);
e->e_u.e_elf.e_nphdr = (phnum != PN_XNUM) ? phnum :
GET_SHDR_MEMBER(sh_info);
e->e_u.e_elf.e_strndx = (strndx != SHN_XINDEX) ? strndx :
GET_SHDR_MEMBER(sh_link);
#undef GET_SHDR_MEMBER
return (1);
}
#define EHDR_INIT(E,SZ) do { \
Elf##SZ##_Ehdr *eh = (E); \
eh->e_ident[EI_MAG0] = ELFMAG0; \
@ -53,8 +101,10 @@ __FBSDID("$FreeBSD$");
void *
_libelf_ehdr(Elf *e, int ec, int allocate)
{
size_t fsz, msz;
void *ehdr;
size_t fsz, msz;
uint16_t phnum, shnum, strndx;
uint64_t shoff;
void (*xlator)(char *_d, char *_s, size_t _c, int _swap);
assert(ec == ELFCLASS32 || ec == ELFCLASS64);
@ -85,8 +135,7 @@ _libelf_ehdr(Elf *e, int ec, int allocate)
if (ehdr != NULL) /* already have a translated ehdr */
return (ehdr);
fsz = gelf_fsize(e, ELF_T_EHDR, (size_t) 1, e->e_version);
fsz = _libelf_fsize(ELF_T_EHDR, ec, e->e_version, (size_t) 1);
assert(fsz > 0);
if (e->e_cmd != ELF_C_WRITE && e->e_rawsize < fsz) {
@ -121,5 +170,35 @@ _libelf_ehdr(Elf *e, int ec, int allocate)
(*xlator)(ehdr, e->e_rawfile, (size_t) 1,
e->e_byteorder != LIBELF_PRIVATE(byteorder));
/*
* If extended numbering is being used, read the correct
* number of sections and program header entries.
*/
if (ec == ELFCLASS32) {
phnum = ((Elf32_Ehdr *) ehdr)->e_phnum;
shnum = ((Elf32_Ehdr *) ehdr)->e_shnum;
shoff = ((Elf32_Ehdr *) ehdr)->e_shoff;
strndx = ((Elf32_Ehdr *) ehdr)->e_shstrndx;
} else {
phnum = ((Elf64_Ehdr *) ehdr)->e_phnum;
shnum = ((Elf64_Ehdr *) ehdr)->e_shnum;
shoff = ((Elf64_Ehdr *) ehdr)->e_shoff;
strndx = ((Elf64_Ehdr *) ehdr)->e_shstrndx;
}
if (shnum >= SHN_LORESERVE ||
(shoff == 0LL && (shnum != 0 || phnum == PN_XNUM ||
strndx == SHN_XINDEX))) {
LIBELF_SET_ERROR(HEADER, 0);
return (NULL);
}
if (shnum != 0 || shoff == 0LL) { /* not using extended numbering */
e->e_u.e_elf.e_nphdr = phnum;
e->e_u.e_elf.e_nscn = shnum;
e->e_u.e_elf.e_strndx = strndx;
} else if (_libelf_load_extended(e, ec, shoff, phnum, strndx) == 0)
return (NULL);
return (ehdr);
}

136
lib/libelf/libelf_extended.c Normal file
View File

@ -0,0 +1,136 @@
/*-
* Copyright (c) 2006 Joseph Koshy
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <assert.h>
#include <libelf.h>
#include "_libelf.h"
/*
* Retrieve section #0, allocating a new section if needed.
*/
static Elf_Scn *
_libelf_getscn0(Elf *e)
{
Elf_Scn *s;
if ((s = STAILQ_FIRST(&e->e_u.e_elf.e_scn)) != NULL)
return (s);
return (_libelf_allocate_scn(e, (size_t) SHN_UNDEF));
}
int
_libelf_setshnum(Elf *e, void *eh, int ec, size_t shnum)
{
Elf_Scn *scn;
if (shnum >= SHN_LORESERVE) {
if ((scn = _libelf_getscn0(e)) == NULL)
return (0);
assert(scn->s_ndx == SHN_UNDEF);
if (ec == ELFCLASS32)
scn->s_shdr.s_shdr32.sh_size = shnum;
else
scn->s_shdr.s_shdr64.sh_size = shnum;
(void) elf_flagshdr(scn, ELF_C_SET, ELF_F_DIRTY);
shnum = 0;
}
if (ec == ELFCLASS32)
((Elf32_Ehdr *) eh)->e_shnum = shnum;
else
((Elf64_Ehdr *) eh)->e_shnum = shnum;
return (1);
}
int
_libelf_setshstrndx(Elf *e, void *eh, int ec, size_t shstrndx)
{
Elf_Scn *scn;
if (shstrndx >= SHN_LORESERVE) {
if ((scn = _libelf_getscn0(e)) == NULL)
return (0);
assert(scn->s_ndx == SHN_UNDEF);
if (ec == ELFCLASS32)
scn->s_shdr.s_shdr32.sh_link = shstrndx;
else
scn->s_shdr.s_shdr64.sh_link = shstrndx;
(void) elf_flagshdr(scn, ELF_C_SET, ELF_F_DIRTY);
shstrndx = SHN_XINDEX;
}
if (ec == ELFCLASS32)
((Elf32_Ehdr *) eh)->e_shstrndx = shstrndx;
else
((Elf64_Ehdr *) eh)->e_shstrndx = shstrndx;
return (1);
}
int
_libelf_setphnum(Elf *e, void *eh, int ec, size_t phnum)
{
Elf_Scn *scn;
if (phnum >= PN_XNUM) {
if ((scn = _libelf_getscn0(e)) == NULL)
return (0);
assert(scn->s_ndx == SHN_UNDEF);
if (ec == ELFCLASS32)
scn->s_shdr.s_shdr32.sh_info = phnum;
else
scn->s_shdr.s_shdr64.sh_info = phnum;
(void) elf_flagshdr(scn, ELF_C_SET, ELF_F_DIRTY);
phnum = PN_XNUM;
}
if (ec == ELFCLASS32)
((Elf32_Ehdr *) eh)->e_phnum = phnum;
else
((Elf64_Ehdr *) eh)->e_phnum = phnum;
return (1);
}

34
lib/libelf/libelf_phdr.c
View File

@ -66,14 +66,14 @@ _libelf_getphdr(Elf *e, int ec)
if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
return (NULL);
phnum = e->e_u.e_elf.e_nphdr;
if (ec == ELFCLASS32) {
eh32 = (Elf32_Ehdr *) ehdr;
phnum = eh32->e_phnum;
phentsize = eh32->e_phentsize;
phoff = (uint64_t) eh32->e_phoff;
} else {
eh64 = (Elf64_Ehdr *) ehdr;
phnum = eh64->e_phnum;
phentsize = eh64->e_phentsize;
phoff = (uint64_t) eh64->e_phoff;
}
@ -112,9 +112,7 @@ _libelf_getphdr(Elf *e, int ec)
void *
_libelf_newphdr(Elf *e, int ec, size_t count)
{
void *ehdr, *nphdr, *ophdr;
Elf32_Ehdr *eh32;
Elf64_Ehdr *eh64;
void *ehdr, *newphdr, *oldphdr;
size_t msz;
if (e == NULL) {
@ -135,31 +133,25 @@ _libelf_newphdr(Elf *e, int ec, size_t count)
assert(msz > 0);
nphdr = NULL;
if (count > 0 && (nphdr = calloc(count, msz)) == NULL) {
newphdr = NULL;
if (count > 0 && (newphdr = calloc(count, msz)) == NULL) {
LIBELF_SET_ERROR(RESOURCE, 0);
return (NULL);
}
if (ec == ELFCLASS32) {
if ((ophdr = (void *) e->e_u.e_elf.e_phdr.e_phdr32) != NULL)
free(ophdr);
e->e_u.e_elf.e_phdr.e_phdr32 = (Elf32_Phdr *) nphdr;
if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr32) != NULL)
free(oldphdr);
e->e_u.e_elf.e_phdr.e_phdr32 = (Elf32_Phdr *) newphdr;
} else {
if ((ophdr = (void *) e->e_u.e_elf.e_phdr.e_phdr64) != NULL)
free(ophdr);
e->e_u.e_elf.e_phdr.e_phdr64 = (Elf64_Phdr *) nphdr;
if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr64) != NULL)
free(oldphdr);
e->e_u.e_elf.e_phdr.e_phdr64 = (Elf64_Phdr *) newphdr;
}
if (ec == ELFCLASS32) {
eh32 = (Elf32_Ehdr *) ehdr;
eh32->e_phnum = count;
} else {
eh64 = (Elf64_Ehdr *) ehdr;
eh64->e_phnum = count;
}
e->e_u.e_elf.e_nphdr = count;
elf_flagphdr(e, ELF_C_SET, ELF_F_DIRTY);
return (nphdr);
return (newphdr);
}