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authorPaolo Bonzini <pbonzini@redhat.com>2017-07-27 16:47:08 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2017-08-01 17:27:33 +0200
commit393c13b940be8f2e5b126cd9f442c12e7ecb4cac (patch)
treeb6f47328533360c9c40e327e1fb17f53b7fc581c
parentf5aa69bdc3418773f26747ca282c291519626ece (diff)
downloadqemu-arm-393c13b940be8f2e5b126cd9f442c12e7ecb4cac.tar.gz
bt: stop the sdp memory allocation craziness
Clang static analyzer reports a memory leak. Actually, the allocated memory escapes here: record->attribute_list[record->attributes].pair = data; but clang is correct that the memory might leak if len is zero. We know it isn't; assert that it is the case. The craziness doesn't end there. The memory is freed by bt_l2cap_sdp_close_ch: g_free(sdp->service_list[i].attribute_list->pair); which actually should have been written like this: g_free(sdp->service_list[i].attribute_list[0].pair); The attribute_list is sorted with qsort; but indeed the first entry of attribute_list should point to "data" even after the qsort, because the first record has id SDP_ATTR_RECORD_HANDLE, whose numeric value is zero. But hang on. The qsort function is static int sdp_attributeid_compare( const struct sdp_service_attribute_s *a, const struct sdp_service_attribute_s *b) { return (int) b->attribute_id - a->attribute_id; } but no one ever writes attribute_id. So it only works if qsort is stable, and who knows what else is broken, but we can fix it by setting attribute_id in the while loop. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--hw/bt/sdp.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/hw/bt/sdp.c b/hw/bt/sdp.c
index f67b3b89c0..3cb60b9495 100644
--- a/hw/bt/sdp.c
+++ b/hw/bt/sdp.c
@@ -580,7 +580,7 @@ static void bt_l2cap_sdp_close_ch(void *opaque)
int i;
for (i = 0; i < sdp->services; i ++) {
- g_free(sdp->service_list[i].attribute_list->pair);
+ g_free(sdp->service_list[i].attribute_list[0].pair);
g_free(sdp->service_list[i].attribute_list);
g_free(sdp->service_list[i].uuid);
}
@@ -720,6 +720,8 @@ static void sdp_service_record_build(struct sdp_service_record_s *record,
len += sdp_attr_max_size(&def->attributes[record->attributes ++].data,
&record->uuids);
}
+
+ assert(len > 0);
record->uuids = pow2ceil(record->uuids);
record->attribute_list =
g_malloc0(record->attributes * sizeof(*record->attribute_list));
@@ -730,12 +732,14 @@ static void sdp_service_record_build(struct sdp_service_record_s *record,
record->attributes = 0;
uuid = record->uuid;
while (def->attributes[record->attributes].data.type) {
+ int attribute_id = def->attributes[record->attributes].id;
record->attribute_list[record->attributes].pair = data;
+ record->attribute_list[record->attributes].attribute_id = attribute_id;
len = 0;
data[len ++] = SDP_DTYPE_UINT | SDP_DSIZE_2;
- data[len ++] = def->attributes[record->attributes].id >> 8;
- data[len ++] = def->attributes[record->attributes].id & 0xff;
+ data[len ++] = attribute_id >> 8;
+ data[len ++] = attribute_id & 0xff;
len += sdp_attr_write(data + len,
&def->attributes[record->attributes].data, &uuid);
@@ -749,10 +753,15 @@ static void sdp_service_record_build(struct sdp_service_record_s *record,
data += len;
}
- /* Sort the attribute list by the AttributeID */
+ /* Sort the attribute list by the AttributeID. The first must be
+ * SDP_ATTR_RECORD_HANDLE so that bt_l2cap_sdp_close_ch can free
+ * the buffer.
+ */
qsort(record->attribute_list, record->attributes,
sizeof(*record->attribute_list),
(void *) sdp_attributeid_compare);
+ assert(record->attribute_list[0].pair == data);
+
/* Sort the searchable UUIDs list for bisection */
qsort(record->uuid, record->uuids,
sizeof(*record->uuid),