From b5d5504aa1e961fc1f87ee7b092bf5ce1a7bf0de Mon Sep 17 00:00:00 2001 From: Jacob Keller Date: Wed, 12 Jul 2017 05:46:09 -0400 Subject: [PATCH] i40e: prevent snprintf format specifier truncation Increase the size of the prefix buffer so that it can hold enough characters for every possible input. Although 20 is enough for all expected inputs, it is possible for the values to be larger than expected, resulting in a possibly truncated string. Additionally, lets use sizeof(prefix) in order to ensure we use the correct size if we need to change the array length in the future. New versions of GCC starting at 7 now include warnings to prevent truncation unless you handle the return code. At most 27 bytes can be written here, so lets just increase the buffer size even if for all expected hw->bus.* values we only needed 20. Signed-off-by: Jacob Keller Tested-by: Andrew Bowers Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/i40e/i40e_common.c | 4 ++-- drivers/net/ethernet/intel/i40evf/i40e_common.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_common.c b/drivers/net/ethernet/intel/i40e/i40e_common.c index 5c36a18..111426b 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_common.c +++ b/drivers/net/ethernet/intel/i40e/i40e_common.c @@ -328,9 +328,9 @@ void i40e_debug_aq(struct i40e_hw *hw, enum i40e_debug_mask mask, void *desc, len = buf_len; /* write the full 16-byte chunks */ if (hw->debug_mask & mask) { - char prefix[20]; + char prefix[27]; - snprintf(prefix, 20, + snprintf(prefix, sizeof(prefix), "i40e %02x:%02x.%x: \t0x", hw->bus.bus_id, hw->bus.device, diff --git a/drivers/net/ethernet/intel/i40evf/i40e_common.c b/drivers/net/ethernet/intel/i40evf/i40e_common.c index d69c2e4..8d3a2bf 100644 --- a/drivers/net/ethernet/intel/i40evf/i40e_common.c +++ b/drivers/net/ethernet/intel/i40evf/i40e_common.c @@ -333,9 +333,9 @@ void i40evf_debug_aq(struct i40e_hw *hw, enum i40e_debug_mask mask, void *desc, len = buf_len; /* write the full 16-byte chunks */ if (hw->debug_mask & mask) { - char prefix[20]; + char prefix[27]; - snprintf(prefix, 20, + snprintf(prefix, sizeof(prefix), "i40evf %02x:%02x.%x: \t0x", hw->bus.bus_id, hw->bus.device, -- 2.7.4