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| author | H. Peter Anvin <hpa@zytor.com> | 2007-11-07 09:26:10 -0800 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2007-11-07 09:26:10 -0800 |
| commit | fd37475e9a5d969969efc811180e7f5e38dafce0 (patch) | |
| tree | b203b78713cd89dc82cd3b9648b4bcc0a476c4d9 | |
| parent | fe66201fedd68a163946635e5db2ad937178f136 (diff) | |
| download | syslinux-fd37475e9a5d969969efc811180e7f5e38dafce0.tar.gz | |
Guard section to avoid future partial-sector-clobber issuessyslinux-3.53-pre3
Create a guard section .uibss that explicitly is covering the
potential partial-sector-clobber zone, and contains items which are
safe to assume will only be used after full image load.
| -rw-r--r-- | isolinux.asm | 4 | ||||
| -rw-r--r-- | layout.inc | 9 | ||||
| -rw-r--r-- | parsecmd.inc | 2 | ||||
| -rw-r--r-- | parseconfig.inc | 2 |
4 files changed, 11 insertions, 6 deletions
diff --git a/isolinux.asm b/isolinux.asm index 3ede48f6..d0e56fca 100644 --- a/isolinux.asm +++ b/isolinux.asm @@ -106,9 +106,7 @@ getcbuf resb trackbufsize ; ends at 4800h ; Some of these are touched before the whole image - ; is loaded. DO NOT move this to .bss, since the beginning - ; of .bss might be clobbered when loading the last fractional - ; sector. + ; is loaded. DO NOT move this to .uibss. section .bss1 alignb 4 ISOFileName resb 64 ; ISO filename canonicalization buffer @@ -58,7 +58,14 @@ STACK_START equ TEXT_START-STACK_SIZE section .adv progbits align=1 follows=.config - section .bss nobits align=16 follows=.adv + ; .uibss contains bss data which is guaranteed to be + ; safe to clobber during the loading of the image. This + ; is because while loading the primary image we will clobber + ; the spillover from the last fractional sector load. + section .uibss nobits align=16 follows=.adv + + ; Normal bss... + section .bss nobits align=16 follows=.uibss ; Reserve space for stack section .stack nobits align=16 start=STACK_START diff --git a/parsecmd.inc b/parsecmd.inc index c19c658c..34314976 100644 --- a/parsecmd.inc +++ b/parsecmd.inc @@ -96,7 +96,7 @@ getcommand: err_badcfg db 'Unknown keyword in syslinux.cfg.', CR, LF, 0 err_noparm db 'Missing parameter in syslinux.cfg.', CR, LF, 0 - section .bss + section .uibss alignb 4 vk_size equ (vk_end + 3) & ~3 VKernelBuf: resb vk_size ; "Current" vkernel diff --git a/parseconfig.inc b/parseconfig.inc index ef1ed112..ab832b6d 100644 --- a/parseconfig.inc +++ b/parseconfig.inc @@ -436,7 +436,7 @@ VKernel db 0 ; Have we seen any "label" statements? IPAppend db 0 ; Default IPAPPEND option %endif - section .bss + section .uibss alignb 4 ; For the good of REP MOVSD command_line resb max_cmd_len+2 ; Command line buffer alignb 4 |