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Fix Elf_auxv table. upx was duplicating AT_PHDR (and others)

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because Linux 2.4.5 supplies many more AT_ entries than before.
First noticed by Sebastian <scut@nb.in-berlin.de>.
	fold_elf86.asm fold_sh86.asm l_lx_sep86.asm
	l_lx_elf.c     l_lx_sh.c     l_lx_sep.c

committer: jreiser <jreiser> 994871296 +0000
This commit is contained in:
John Reiser
2001-07-11 17:08:16 +00:00
parent caca5ffa12
commit ef17dc10ca
6 changed files with 186 additions and 129 deletions
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src/stub/fold_elf86.asm
+53 -34
View File
@@ -24,6 +24,7 @@
; markus@oberhumer.com ml1050@cdata.tvnet.hu jreiser@BitWagon.com
;
%define PAGE_SIZE ( 1<<12)
%define szElf32_Ehdr 0x34
%define szElf32_Phdr 8*4
%define e_entry (16 + 2*2 + 4)
@@ -31,7 +32,9 @@
%define szb_info 12
%define szl_info 12
%define szp_info 12
%define a_type 0
%define a_val 4
%define sz_auxv 8
%define __NR_munmap 91
@@ -46,17 +49,59 @@ fold_begin: ; enter: %ebx= &Elf32_Ehdr of this program
pop eax ; discard &sz_uncompressed
pop eax ; discard sz_uncompressed
; Move argc,argv,envp down so that we can insert more Elf_auxv entries.
; Move argc,argv,envp down to make room for complete Elf_auxv table.
; Linux kernel 2.4.2 and earlier give only AT_HWCAP and AT_PLATFORM
; because we have no PT_INTERP. Linux kernel 2.4.5 (and later?)
; give not quite everything. It is simpler and smaller code for us
; to generate a "complete" table where Elf_auxv[k -1].a_type = k.
; ld-linux.so.2 depends on AT_PHDR and AT_ENTRY, for instance
%define PAGE_SIZE ( 1<<12)
%define OVERHEAD 2048
%define MAX_ELF_HDR 512
%define AT_NULL 0
%define AT_IGNORE 1
%define AT_PHDR 3
%define AT_NUMBER 20
mov esi, esp
sub esp, byte 6*8 ; AT_PHENT, AT_PHNUM, AT_PAGESZ, AT_ENTRY, AT_PHDR, AT_NULL
sub esp, sz_auxv * AT_NUMBER ; more than 128 bytes
mov edi, esp
call do_auxv
do_auxv: ; entry: %esi=src = &argc; %edi=dst. exit: %edi= &AT_NULL
; cld
L10: ; move argc+argv
lodsd
stosd
test eax,eax
jne L10
L20: ; move envp
lodsd
stosd
test eax,eax
jne L20
; complete Elf_auxv table full of AT_IGNORE
push edi ; save base of resulting table
inc eax ; convert 0 to AT_IGNORE
mov ecx, 2 * (AT_NUMBER -1)
rep stosd
dec eax ; convert AT_IGNORE into AT_NULL
stosd ; terminate Elf_auxv
stosd
pop edi ; base of resulting table
L30: ; distribute existing Elf32_auxv into new table
lodsd
test eax,eax ; AT_NULL ?
xchg eax,edx
lodsd
je L40
mov [a_type + sz_auxv*(edx -1) + edi], edx
mov [a_val + sz_auxv*(edx -1) + edi], eax
jmp L30
L40:
%define OVERHEAD 2048
%define MAX_ELF_HDR 512
push ebx ; save &Elf32_Ehdr of this stub
sub esp, dword MAX_ELF_HDR + OVERHEAD
@@ -67,14 +112,14 @@ fold_begin: ; enter: %ebx= &Elf32_Ehdr of this program
mov edx, esp ;
mov ecx, [4+ eax] ; length of compressed ELF headers
add ecx, byte szb_info
pusha ; (AT_next, sz_cpr, f_expand, &tmp_ehdr, {sz_unc, &tmp}, {sz_cpr, &b1st_info} )
pusha ; (AT_table, sz_cpr, f_expand, &tmp_ehdr, {sz_unc, &tmp}, {sz_cpr, &b1st_info} )
EXTERN upx_main
call upx_main ; returns entry address
add esp, dword 8*4 + MAX_ELF_HDR + OVERHEAD ; remove 8 params, temp space
pop ebx ; &Elf32_Ehdr of this stub
push eax ; save entry address
mov edi, [a_val + edi] ; AT_PHDR
mov edi, [a_val + sz_auxv * (AT_PHDR -1) + edi]
find_hatch:
push edi
EXTERN make_hatch
@@ -104,31 +149,5 @@ EXTERN make_hatch
mov eax, __NR_munmap ; do not dirty the stack with push byte + pop
jmp edx ; unmap ourselves via escape hatch, then goto entry
do_auxv: ; entry: %esi=src = &argc; %edi=dst. exit: %edi= &AT_NULL
; cld
L10: ; move argc+argv
lodsd
stosd
test eax,eax
jne L10
L20: ; move envp
lodsd
stosd
test eax,eax
jne L20
L30: ; move existing Elf32_auxv
lodsd
stosd
test eax,eax ; AT_NULL ?
lodsd
stosd
jne L30
sub edi, byte 8 ; point to AT_NULL
ret
; vi:ts=8:et:nowrap