lib-ssl-iostream: ostream-openssl - Allocate at most IO_BLOCK_SIZE initial buffer

Otherwise we might attempt to allocate way too large buffers. This has not caused
issues yet, except with max_buffer_size=SIZE_T, which has been causing us to allocate
0-sized buffers.

diff --git a/src/lib-ssl-iostream/ostream-openssl.c b/src/lib-ssl-iostream/ostream-openssl.c
index ed80bf0acf68fdcaa57fc8c3f5a4d0a1a0a3255b..2e653c7e18d983c54dbf8bd163c6a5598bdf9d43 100644 (file)
--- a/src/lib-ssl-iostream/ostream-openssl.c
+++ b/src/lib-ssl-iostream/ostream-openssl.c
@@ -57,7 +57,8 @@ o_stream_ssl_buffer(struct ssl_ostream *sstream, const struct const_iovec *iov,
        unsigned int i;
 
        if (sstream->buffer == NULL)
-               sstream->buffer = buffer_create_dynamic(default_pool, sstream->ostream.max_buffer_size);
+               sstream->buffer = buffer_create_dynamic(default_pool,
+                       I_MIN(IO_BLOCK_SIZE, sstream->ostream.max_buffer_size));
 
        skip_left = bytes_sent;
        for (i = 0; i < iov_count; i++) {