Thread (3 messages) 3 messages, 3 authors, 2025-03-10

Re: [PATCH net-next] eth: fbnic: fix memory corruption in fbnic_tlv_attr_get_string()

From: Lee Trager <hidden>
Date: 2025-03-07 22:59:36
Also in: kernel-janitors, lkml

On 3/7/25 1:28 AM, Dan Carpenter wrote:
quoted hunk ↗ jump to hunk
This code is trying to ensure that the last byte of the buffer is a NUL
terminator.  However, the problem is that attr->value[] is an array of
__le32, not char, so it zeroes out 4 bytes way beyond the end of the
buffer.  Cast the buffer to char to address this.

Fixes: e5cf5107c9e4 ("eth: fbnic: Update fbnic_tlv_attr_get_string() to work like nla_strscpy()")
Signed-off-by: Dan Carpenter <redacted>
---
  drivers/net/ethernet/meta/fbnic/fbnic_tlv.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_tlv.c b/drivers/net/ethernet/meta/fbnic/fbnic_tlv.c
index d558d176e0df..517ed8b2f1cb 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_tlv.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_tlv.c
@@ -261,7 +261,7 @@ ssize_t fbnic_tlv_attr_get_string(struct fbnic_tlv_msg *attr, char *dst,
  		return -E2BIG;
  
  	srclen = le16_to_cpu(attr->hdr.len) - sizeof(*attr);
-	if (srclen > 0 && attr->value[srclen - 1] == '\0')
+	if (srclen > 0 && ((char *)attr->value)[srclen - 1] == '\0')
  		srclen--;
  
  	if (srclen >= dstsize) {
Thanks for catching that. While I didn't see any negative effect without 
it I have verified on hardware this patch works.

Reviewed-by: Lee Trager <redacted>

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