Commit 7151062c authored Mar 17, 2025 by Peter Seiderer Committed by Jakub Kicinski Mar 24, 2025

net: pktgen: add strict buffer parsing index check



Add strict buffer parsing index check to avoid the following Smatch
warning:

  net/core/pktgen.c:877 get_imix_entries()
  warn: check that incremented offset 'i' is capped

Checking the buffer index i after every get_user/i++ step and returning
with error code immediately avoids the current indirect (but correct)
error handling.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/netdev/36cf3ee2-38b1-47e5-a42a-363efeb0ace3@stanley.mountain/


Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250317090401.1240704-1-ps.report@gmx.net


Signed-off-by: Jakub Kicinski <kuba@kernel.org>

parent fd882536

net/core/pktgen.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -856,6 +856,9 @@ static ssize_t get_imix_entries(const char __user *buffer,
		if (pkt_dev->n_imix_entries >= MAX_IMIX_ENTRIES)
		return -E2BIG;

		if (i >= maxlen)
		return -EINVAL;

		max = min(10, maxlen - i);
		len = num_arg(&buffer[i], max, &size);
		if (len < 0)
		@@ -869,6 +872,8 @@ static ssize_t get_imix_entries(const char __user *buffer,
		if (c != ',')
		return -EINVAL;
		i++;
		if (i >= maxlen)
		return -EINVAL;

		if (size < 14 + 20 + 8)
		size = 14 + 20 + 8;
		@@ -911,6 +916,9 @@ static ssize_t get_labels(const char __user *buffer,
		if (n >= MAX_MPLS_LABELS)
		return -E2BIG;

		if (i >= maxlen)
		return -EINVAL;

		max = min(8, maxlen - i);
		len = hex32_arg(&buffer[i], max, &tmp);
		if (len < 0)