sh: Fix formal overflow in pointer arithmetic

The intention is to lower the value of the pointer, which according to ubsan
cannot be done by adding an unsigned quantity.

Reported by:	kevans
Approved by:	re (kib)
MFC after:	1 week
This commit is contained in:
Jilles Tjoelker 2018-09-05 19:16:09 +00:00
parent ce9eea6425
commit 4269bba2eb
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=338473

View File

@ -896,7 +896,7 @@ reprocess(int startloc, int flag, int subtype, int quoted,
startp = stackblock() + startloc;
len = expdest - startp;
if (len >= SIZE_MAX / 2)
if (len >= SIZE_MAX / 2 || len > PTRDIFF_MAX)
abort();
INTOFF;
if (len >= buflen) {
@ -912,7 +912,7 @@ reprocess(int startloc, int flag, int subtype, int quoted,
INTON;
memcpy(buf, startp, len);
buf[len] = '\0';
STADJUST(-len, expdest);
STADJUST(-(ptrdiff_t)len, expdest);
for (zpos = 0;;) {
zlen = strlen(buf + zpos);
strtodest(buf + zpos, flag, subtype, quoted, dst);