[PATCH v2 1/7] examples/server_node_efd: fix format overflow

Stephen Hemminger
2025-11-11T22:19:08Z

If format-truncation is enabled, the compiler detects a string overflow
since the snprintf() is putting ethernet address and new line
in buffer only sized for the address.

Since get_rx_queue_name() is used to create a ring name.
The buffer should be sized to be a valid ring name.
This fixes some format-overflow warnings and also corrects
for future errors.

Fixes: 39aad0e88c58 ("examples/flow_distributor: new example to demonstrate EFD")
Cc: stable@dpdk.org

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
examples/server_node_efd/efd_server/main.c | 2 +-
examples/server_node_efd/shared/common.h | 3 ++-
2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/examples/server_node_efd/efd_server/main.c b/examples/server_node_efd/efd_server/main.c
index 75ff0ea532..62c3f4a16d 100644
--- a/examples/server_node_efd/efd_server/main.c
+++ b/examples/server_node_efd/efd_server/main.c
@@ -68,7 +68,7 @@ static const char *
get_printable_mac_addr(uint16_t port)
{
static const char err_address[] = "00:00:00:00:00:00";
- static char addresses[RTE_MAX_ETHPORTS][sizeof(err_address)];
+ static char addresses[RTE_MAX_ETHPORTS][RTE_ETHER_ADDR_FMT_SIZE + 1];
struct rte_ether_addr mac;
int ret;

diff --git a/examples/server_node_efd/shared/common.h b/examples/server_node_efd/shared/common.h
index e1ab7e62b7..6726e2031e 100644
--- a/examples/server_node_efd/shared/common.h
+++ b/examples/server_node_efd/shared/common.h
@@ -58,8 +58,9 @@ get_rx_queue_name(unsigned int id)
/*
* Buffer for return value. Size calculated by %u being replaced
* by maximum 3 digits (plus an extra byte for safety)
+ * Used as ring name, so upper limit is ring name size.
*/
- static char buffer[sizeof(MP_NODE_RXQ_NAME) + 2];
+ static char buffer[RTE_RING_NAMESIZE];

snprintf(buffer, sizeof(buffer), MP_NODE_RXQ_NAME, id);
return buffer;
--
2.51.0