protobuf-c 1.0.0 added a new 'allocator' field to ProtobufCBufferSimple that controls memory allocation, which must be NULL in order to request the default system allocator. Allocating ProtobufCBufferSimple objects on the stack without zeroing the entire object can result in protobuf-c's memory allocation functions dereferencing a garbage pointer. Note that the use of the zero initializer in this instance generates a warning on some gcc versions: dnstap.c: In function 'dt_pack': dnstap.c:26:2: warning: missing braces around initializer [-Wmissing-braces] ProtobufCBufferSimple sbuf = {0}; ^ dnstap.c:26:2: warning: (near initialization for 'sbuf.base') [-Wmissing-braces] This warning is spurious and was fixed recently: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53119 https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=211289 --- src/dnstap/dnstap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/dnstap/dnstap.c b/src/dnstap/dnstap.c index 41d42e7..cf3770c 100644 --- a/src/dnstap/dnstap.c +++ b/src/dnstap/dnstap.c @@ -23,7 +23,7 @@ uint8_t* dt_pack(const Dnstap__Dnstap *d, uint8_t **buf, size_t *sz) { - ProtobufCBufferSimple sbuf; + ProtobufCBufferSimple sbuf = {0}; sbuf.base.append = protobuf_c_buffer_simple_append; sbuf.len = 0;