From 0346000aaab8cf8baf4ae40c48a5779a03971e80 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Wed, 9 Jul 2025 13:59:10 -0700 Subject: [PATCH] eth: fbnic: fix ubsan complaints about OOB accesses UBSAN complains that we reach beyond the end of the log entry: UBSAN: array-index-out-of-bounds in drivers/net/ethernet/meta/fbnic/fbnic_fw_log.c:94:50 index 71 is out of range for type 'char [*]' Call Trace: ubsan_epilogue+0x5/0x2b fbnic_fw_log_write+0x120/0x960 fbnic_fw_parse_logs+0x161/0x210 We're just taking the address of the character after the array, so this really seems like something that should be legal. But whatever, easy enough to silence by doing direct pointer math. Fixes: c2b93d6beca8 ("eth: fbnic: Create ring buffer for firmware logs") Reviewed-by: Alexander Duyck Reviewed-by: Jacob Keller Link: https://patch.msgid.link/20250709205910.3107691-1-kuba@kernel.org Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/meta/fbnic/fbnic_fw_log.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_fw_log.c b/drivers/net/ethernet/meta/fbnic/fbnic_fw_log.c index 38749d47cee67..c1663f0422453 100644 --- a/drivers/net/ethernet/meta/fbnic/fbnic_fw_log.c +++ b/drivers/net/ethernet/meta/fbnic/fbnic_fw_log.c @@ -91,16 +91,16 @@ int fbnic_fw_log_write(struct fbnic_dev *fbd, u64 index, u32 timestamp, entry = log->data_start; } else { head = list_first_entry(&log->entries, typeof(*head), list); - entry = (struct fbnic_fw_log_entry *)&head->msg[head->len + 1]; - entry = PTR_ALIGN(entry, 8); + entry_end = head->msg + head->len + 1; + entry = PTR_ALIGN(entry_end, 8); } - entry_end = &entry->msg[msg_len + 1]; + entry_end = entry->msg + msg_len + 1; /* We've reached the end of the buffer, wrap around */ if (entry_end > log->data_end) { entry = log->data_start; - entry_end = &entry->msg[msg_len + 1]; + entry_end = entry->msg + msg_len + 1; } /* Make room for entry by removing from tail. */ -- 2.47.2