cirno/plan9port
1
0
Fork 0
mirror of https://github.com/9fans/plan9port.git synced 2025-01-12 11:10:07 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

sam: avoid out-of-bounds read in rterm

Browse source 
Usually r->nused < r->nalloc and the read is in bounds.
But it could in theory be right on the line and reading
past the end of the allocation.

Make it safe but preserve as much of the old semantics
as possible. This use of rterm appears to be only for
optimization purposes so the result does not matter
for correctness.
This commit is contained in:
Russ Cox 2021-01-14 10:05:50 -05:00
parent 6a80119eb5
commit 3ccd61629b
1 changed files with 2 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
src/cmd/sam/rasp.c
View file

@ -283,8 +283,8 @@ rterm(List *r, Posn p1)
for(p = 0,i = 0; i<r->nused && p+L(i)<=p1; p+=L(i++))
;
if(i==r->nused && (i==0 || !T(i-1)))
return 0;
if(i==r->nused)
return i > 0 && T(i-1);
return T(i);
}