netdev - [PATCH net-next 11/11] ixgbe: fix end of loop test in ixgbe_set_vf

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20231019173227.3175575-12-jacob.e.keller@intel.com>
Date: Thu, 19 Oct 2023 10:32:27 -0700
From: Jacob Keller <jacob.e.keller@...el.com>
To: netdev@...r.kernel.org,
	David Miller <davem@...emloft.net>,
	Jakub Kicinski <kuba@...nel.org>
Cc: Dan Carpenter <dan.carpenter@...aro.org>,
	Simon Horman <horms@...nel.org>,
	Jesse Brandeburg <jesse.brandeburg@...el.com>,
	Rafal Romanowski <rafal.romanowski@...el.com>,
	Jacob Keller <jacob.e.keller@...el.com>
Subject: [PATCH net-next 11/11] ixgbe: fix end of loop test in ixgbe_set_vf_macvlan()

From: Dan Carpenter <dan.carpenter@...aro.org>

The list iterator in a list_for_each_entry() loop can never be NULL.
If the loop exits without hitting a break then the iterator points
to an offset off the list head and dereferencing it is an out of
bounds access.

Before we transitioned to using list_for_each_entry() loops, then
it was possible for "entry" to be NULL and the comments mention
this.  I have updated the comments to match the new code.

Fixes: c1fec890458a ("ethernet/intel: Use list_for_each_entry() helper")
Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
Reviewed-by: Simon Horman <horms@...nel.org>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@...el.com>
Tested-by: Rafal Romanowski <rafal.romanowski@...el.com>
Signed-off-by: Jacob Keller <jacob.e.keller@...el.com>
---
 .../net/ethernet/intel/ixgbe/ixgbe_sriov.c    | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
index cd593f5719e1..9cfdfa8a4355 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
@@ -640,6 +640,7 @@ static int ixgbe_set_vf_macvlan(struct ixgbe_adapter *adapter,
 				int vf, int index, unsigned char *mac_addr)
 {
 	struct vf_macvlans *entry;
+	bool found = false;
 	int retval = 0;
 
 	if (index <= 1) {
@@ -661,22 +662,22 @@ static int ixgbe_set_vf_macvlan(struct ixgbe_adapter *adapter,
 	if (!index)
 		return 0;
 
-	entry = NULL;
-
 	list_for_each_entry(entry, &adapter->vf_mvs.l, l) {
-		if (entry->free)
+		if (entry->free) {
+			found = true;
 			break;
+		}
 	}
 
 	/*
 	 * If we traversed the entire list and didn't find a free entry
-	 * then we're out of space on the RAR table.  Also entry may
-	 * be NULL because the original memory allocation for the list
-	 * failed, which is not fatal but does mean we can't support
-	 * VF requests for MACVLAN because we couldn't allocate
-	 * memory for the list management required.
+	 * then we're out of space on the RAR table.  It's also possible
+	 * for the &adapter->vf_mvs.l list to be empty because the original
+	 * memory allocation for the list failed, which is not fatal but does
+	 * mean we can't support VF requests for MACVLAN because we couldn't
+	 * allocate memory for the list management required.
 	 */
-	if (!entry || !entry->free)
+	if (!found)
 		return -ENOSPC;
 
 	retval = ixgbe_add_mac_filter(adapter, mac_addr, vf);
-- 
2.41.0