selftests/bpf: Test packet range of pointers sharing an idgrafted

Add tests where two packet pointers share an id and tightening one
pointer's umax from its var_off would put it less than their constant
distance from the other's umax: with an index & 0x38 capped at 50, the
base pointer keeps umax 50, so the pointer 8 bytes further on must keep
umax 58, even though its known bits allow at most 56.

These refused a valid program or accepted an out-of-bounds access before
the fix:

- check the advanced copy, load through the base: valid, was refused;
- check the base, load the byte at base + 1 through a copy advanced by
  8: was accepted;
- check base + 4, load 4 bytes at base + 2 through base + 8: reads two
  bytes past the checked range, was accepted;
- the same as the second with data_meta pointers checked against data:
  was accepted.

These pass with and without the fix and cover nearby paths:

- subtract an unknown scalar from a checked pointer and load below it
  (the range is kept across a new id);
- reach a load through two paths whose checks cover 8 and 7 bytes after
  the loaded pointer; the second path must not be pruned by the first;
- spill a copy of a pointer, check the pointer, fill the copy and load
  one byte past the checked range: the load is refused, and the copy
  has the range of the check.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20261001145255.855630-2-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/net/mac80211/debugfs_netdev.h b/net/mac80211/debugfs_netdev.h
new file mode 100644
index 000000000..a02ec0a41
--- /dev/null
+++ b/net/mac80211/debugfs_netdev.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Portions:
+ * Copyright (C) 2023 Intel Corporation
+ */
+/* routines exported for debugfs handling */
+
+#ifndef __IEEE80211_DEBUGFS_NETDEV_H
+#define __IEEE80211_DEBUGFS_NETDEV_H
+
+#include "ieee80211_i.h"
+
+#ifdef CONFIG_MAC80211_DEBUGFS
+void ieee80211_debugfs_remove_netdev(struct ieee80211_sub_if_data *sdata);
+void ieee80211_debugfs_rename_netdev(struct ieee80211_sub_if_data *sdata);
+void ieee80211_debugfs_recreate_netdev(struct ieee80211_sub_if_data *sdata,
+				       bool mld_vif);
+
+void ieee80211_link_debugfs_add(struct ieee80211_link_data *link);
+void ieee80211_link_debugfs_remove(struct ieee80211_link_data *link);
+
+void ieee80211_link_debugfs_drv_add(struct ieee80211_link_data *link);
+void ieee80211_link_debugfs_drv_remove(struct ieee80211_link_data *link);
+#else
+static inline void ieee80211_debugfs_remove_netdev(
+	struct ieee80211_sub_if_data *sdata)
+{}
+static inline void ieee80211_debugfs_rename_netdev(
+	struct ieee80211_sub_if_data *sdata)
+{}
+static inline void ieee80211_debugfs_recreate_netdev(
+	struct ieee80211_sub_if_data *sdata, bool mld_vif)
+{}
+static inline void ieee80211_link_debugfs_add(struct ieee80211_link_data *link)
+{}
+static inline void ieee80211_link_debugfs_remove(struct ieee80211_link_data *link)
+{}
+
+static inline void ieee80211_link_debugfs_drv_add(struct ieee80211_link_data *link)
+{}
+static inline void ieee80211_link_debugfs_drv_remove(struct ieee80211_link_data *link)
+{}
+#endif
+
+#endif /* __IEEE80211_DEBUGFS_NETDEV_H */