gzip: correctly bounds-check output buffer
The output buffer size must not be reset by the gzip decoder or there
is a risk of overflowing memory during decompression.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/gunzip.c b/lib/gunzip.c
index 9959781..35abfb38 100644
--- a/lib/gunzip.c
+++ b/lib/gunzip.c
@@ -89,13 +89,13 @@
s.avail_out = dstlen;
do {
r = inflate(&s, Z_FINISH);
- if (r != Z_STREAM_END && r != Z_BUF_ERROR && stoponerr == 1) {
+ if (stoponerr == 1 && r != Z_STREAM_END &&
+ (s.avail_out == 0 || r != Z_BUF_ERROR)) {
printf("Error: inflate() returned %d\n", r);
inflateEnd(&s);
return -1;
}
s.avail_in = *lenp - offset - (int)(s.next_out - (unsigned char*)dst);
- s.avail_out = dstlen;
} while (r == Z_BUF_ERROR);
*lenp = s.next_out - (unsigned char *) dst;
inflateEnd(&s);