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authorH. Peter Anvin <hpa@zytor.com>2009-06-01 14:47:45 -0700
committerH. Peter Anvin <hpa@zytor.com>2009-06-01 14:47:45 -0700
commit7b5d546fdbf1d330ecc18d4c5b5d15db7cb5c783 (patch)
tree0545f8454ce6ba9215c4f322d8ffad401da367ec /core
parentd24dee1326c10b0488fe0bdaccb819854a2325c8 (diff)
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prepcore: error out if the compressed image is too large to load
Export, from each loader stage, the symbol MaxLMA which indicates to prepcore how big the image is allowed to be. Change prepcore to enforce this limit and to error out otherwise. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'core')
-rw-r--r--core/common.inc4
-rw-r--r--core/diskstart.inc2
-rw-r--r--core/isolinux.asm2
-rw-r--r--core/layout.inc15
-rw-r--r--core/prefix.inc17
-rw-r--r--core/pxelinux.asm4
6 files changed, 28 insertions, 16 deletions
diff --git a/core/common.inc b/core/common.inc
index ad64c23c..80dbb4f9 100644
--- a/core/common.inc
+++ b/core/common.inc
@@ -18,3 +18,7 @@
%include "strcpy.inc" ; strcpy()
%include "idle.inc" ; Idle handling
%include "adv.inc" ; Auxillary Data Vector
+
+; Note: the prefix section is included late, to avoid problems with some
+; versions of NASM that had issues with forward references to EQU symbols.
+%include "prefix.inc" ; Prefix section for prepcore
diff --git a/core/diskstart.inc b/core/diskstart.inc
index b713a1ea..b8047264 100644
--- a/core/diskstart.inc
+++ b/core/diskstart.inc
@@ -668,8 +668,8 @@ rl_checkpt_off equ ($-$$)
; Sector pointers
alignz 4
- global MaxInitDataSize
MaxInitDataSize equ 96 << 10
+MaxLMA equ 0x7c00+SECTOR_SIZE+MaxInitDataSize
SectorPtrs times MaxInitDataSize >> SECTOR_SHIFT dd 0
SectorPtrsEnd equ $
diff --git a/core/isolinux.asm b/core/isolinux.asm
index 37c14744..b2c9c986 100644
--- a/core/isolinux.asm
+++ b/core/isolinux.asm
@@ -431,6 +431,8 @@ found_file:
; address (7C00h) is *not* 2K-sector-aligned, the safest
; way to deal with this is to load into the xfer_buf_seg
; and then copy the data in place.
+MaxLMA equ xfer_buf_seg << 4
+
mov bx,(7C00h+SECTOR_SIZE) >> 4
mov bp,[ImageSectors]
diff --git a/core/layout.inc b/core/layout.inc
index e2c7cbc5..fe292b14 100644
--- a/core/layout.inc
+++ b/core/layout.inc
@@ -134,18 +134,3 @@ pktbuf_seg equ cache_seg ; PXELINUX packet buffers
%endif
comboot_seg equ real_mode_seg ; COMBOOT image loading zone
-
-;
-; The prefix is a small structure that prefaces the actual code;
-; it gives the compression program necessary information.
-;
-
- section .prefix nowrite progbits align=16
-pfx_start dd _start ; Start of raw chunk
-pfx_compressed dd __pm_code_lma ; Start of compressed chunk
-pfx_cdatalen dd lzo_data_size ; Pointer to compressed size field
-%if IS_ISOLINUX
-pfx_checksum dd bi_length ; File length and checksum fields
-%else
-pfx_checksum dd 0 ; No checksum
-%endif
diff --git a/core/prefix.inc b/core/prefix.inc
new file mode 100644
index 00000000..9c8724b5
--- /dev/null
+++ b/core/prefix.inc
@@ -0,0 +1,17 @@
+;
+; The prefix is a small structure that prefaces the actual code;
+; it gives the compression program necessary information.
+;
+
+ section .prefix nowrite progbits align=16
+pfx_start dd _start ; Start of raw chunk
+pfx_compressed dd __pm_code_lma ; Start of compressed chunk
+pfx_cdatalen dd lzo_data_size ; Pointer to compressed size field
+%if IS_ISOLINUX
+pfx_checksum dd bi_length ; File length and checksum fields
+%else
+pfx_checksum dd 0 ; No checksum
+%endif
+pfx_maxlma dd MaxLMA ; Maximum size
+
+ section .text16
diff --git a/core/pxelinux.asm b/core/pxelinux.asm
index bb536a6c..b866369c 100644
--- a/core/pxelinux.asm
+++ b/core/pxelinux.asm
@@ -224,6 +224,10 @@ packet_buf_size equ $-packet_buf
StackBuf equ $-44 ; Base of stack if we use our own
StackTop equ StackBuf
+ ; PXE loads the whole file, but assume it can't be more
+ ; than (384-31)K in size.
+MaxLMA equ 384*1024
+
;
; Primary entry point.
;