Re: [PATCH net-next v3 08/10] net: pktgen: fix access outside of user given buffer in pktgen_if_write()

Hello Paolo,

On Tue, 4 Feb 2025 11:40:21 +0100, Paolo Abeni pabeni@redhat.com wrote:

Hi,

On 2/3/25 6:01 PM, Peter Seiderer wrote:

...

@@ -806,6 +812,9 @@ static long num_arg(const char __user *user_buffer, unsigned long maxlen, if ((c >= '0') && (c <= '9')) { *num *= 10; *num += c - '0';

• } else if (i == 0) {
  

• 	// no valid character parsed, error out
  

Minor nit: please don't use C99 comments, even for single line one.

Fixed...

...

• 	return -EINVAL;
  

  } else break; }

@@ -816,6 +825,9 @@ static int strn_len(const char __user * user_buffer, unsigned int maxlen) { int i;

• if (!maxlen)

• return -EINVAL;
  

It looks like this check is not needed? strn_len() will return 0 and the caller will read 0 bytes from the user_buffer.

Checked all call sites, your are right, fixed in next patch iteration...

...

@@ -882,39 +897,45 @@ static ssize_t get_imix_entries(const char __user *buffer, pkt_dev->imix_entries[pkt_dev->n_imix_entries].weight = weight;

i += len;

• pkt_dev->n_imix_entries++;
  

• if (i >= maxlen)
  

• 	break;
  

  if (get_user(c, &buffer[i])) return -EFAULT;

• i++;

• pkt_dev->n_imix_entries++;
  

  } while (c == ' ');

  return i;

}

-static ssize_t get_labels(const char __user *buffer, struct pktgen_dev *pkt_dev) +static ssize_t get_labels(const char __user *buffer, int maxlen, struct pktgen_dev *pkt_dev) { unsigned int n = 0; char c;

• ssize_t i = 0;
• int len;

• int i = 0, max, len;

Minor nit: since you are touching the variables declaration, please fix them to respect the reverse christmas tree order.

Fixed...

This patch is quite large and mixes several things. I'll split out at least the strn_len() caller fixes (possibly even the num_arg() and hex32_arg() ones) and the refactoring in pktgen_if_write().

Done in the next patch iteration....

Thanks for review!

Regards, Peter

/P