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authorDaniel Stenberg <daniel@haxx.se>2018-03-08 10:33:16 +0100
committerDaniel Stenberg <daniel@haxx.se>2018-03-12 07:47:07 +0100
commitd52dc4760f6d9ca1937eefa2093058a952465128 (patch)
treebd9dcbf19b67a557feafb56075536b283e6a63c7
parentddb879c6ae3187dab50430fe0e9b0ba8653204d3 (diff)
readwrite: make sure excess reads don't go beyond buffer end
CVE-2018-1000122 Bug: https://curl.haxx.se/docs/adv_2018-b047.html Detected by OSS-fuzz
-rw-r--r--lib/transfer.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/lib/transfer.c b/lib/transfer.c
index c46ac25f4..fd9af3155 100644
--- a/lib/transfer.c
+++ b/lib/transfer.c
@@ -808,10 +808,15 @@ static CURLcode readwrite_data(struct Curl_easy *data,
} /* if(!header and data to read) */
- if(conn->handler->readwrite &&
- (excess > 0 && !conn->bits.stream_was_rewound)) {
+ if(conn->handler->readwrite && excess && !conn->bits.stream_was_rewound) {
/* Parse the excess data */
k->str += nread;
+
+ if(&k->str[excess] > &k->buf[data->set.buffer_size]) {
+ /* the excess amount was too excessive(!), make sure
+ it doesn't read out of buffer */
+ excess = &k->buf[data->set.buffer_size] - k->str;
+ }
nread = (ssize_t)excess;
result = conn->handler->readwrite(data, conn, &nread, &readmore);