Make sure nSelectors is not out of range

nSelectors is used in a loop from 0 to nSelectors to access selectorMtf
which is
	UChar    selectorMtf[BZ_MAX_SELECTORS];
so if nSelectors is bigger than BZ_MAX_SELECTORS it'll do an invalid memory
access

Fixes out of bounds access discovered while fuzzying karchive

This was reported as CVE-2019-12900
BZ2_decompress in decompress.c in bzip2 through 1.0.6 has an
out-of-bounds write when there are many selectors.
This commit is contained in:
Albert Astals Cid 2019-05-28 19:35:18 +02:00 committed by Mark Wielaard
parent 16f2c753f9
commit 7ed62bfb46

View File

@ -287,7 +287,7 @@ Int32 BZ2_decompress ( DState* s )
GET_BITS(BZ_X_SELECTOR_1, nGroups, 3);
if (nGroups < 2 || nGroups > 6) RETURN(BZ_DATA_ERROR);
GET_BITS(BZ_X_SELECTOR_2, nSelectors, 15);
if (nSelectors < 1) RETURN(BZ_DATA_ERROR);
if (nSelectors < 1 || nSelectors > BZ_MAX_SELECTORS) RETURN(BZ_DATA_ERROR);
for (i = 0; i < nSelectors; i++) {
j = 0;
while (True) {