backquote expansion bug in /bin/sh ( fix included )

[Simon 'corecode' Schubert]

On 05.02.2004, at 02:35, Vincent Labrecque wrote:
"/usr/bin/cvs" -z3 -Q diff -N -b -B -kk  -r 1.3 -r 1.3.2.1 "expand.c"
Index: expand.c
===================================================================
RCS file: /usr/dfly/repo/src/bin/sh/expand.c,v
retrieving revision 1.3
retrieving revision 1.3.2.1
diff -b -B -r1.3 -r1.3.2.1
472c472
<       for (p--; lastc == '\n'; lastc = *--p)
---
      for ( ; *(dest-1) == '\n' ; )
It lacks some bounds checking. Under sucky circumstances both old and
new version will eat back up the stack...
How about (didn't try tho):

while (*(dest - 1) == '\n' && dest - stackblock() > startloc)
 Hm, i'd put the bound checking _before_ the *(dest-1) access, 
otherwise
it's a bit useless.
True, true... I somehow thought this way round would be better, but 
don't ask me how I came to this conclusion... Late night logic :)

cheers
  simon
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