From 2f8ceeba670610d66f77def32011f48de951d781 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 17 Feb 2026 13:05:26 +0100 Subject: [PATCH] wifi: radiotap: reject radiotap with unknown bits commit c854758abe0b8d86f9c43dc060ff56a0ee5b31e0 upstream. The radiotap parser is currently only used with the radiotap namespace (not with vendor namespaces), but if the undefined field 18 is used, the alignment/size is unknown as well. In this case, iterator->_next_ns_data isn't initialized (it's only set for skipping vendor namespaces), and syzbot points out that we later compare against this uninitialized value. Fix this by moving the rejection of unknown radiotap fields down to after the in-namespace lookup, so it will really use iterator->_next_ns_data only for vendor namespaces, even in case undefined fields are present. Cc: stable@vger.kernel.org Fixes: 33e5a2f776e3 ("wireless: update radiotap parser") Reported-by: syzbot+b09c1af8764c0097bb19@syzkaller.appspotmail.com Closes: https://lore.kernel.org/r/69944a91.a70a0220.2c38d7.00fc.GAE@google.com Link: https://patch.msgid.link/20260217120526.162647-2-johannes@sipsolutions.net Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/wireless/radiotap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/wireless/radiotap.c b/net/wireless/radiotap.c index 326faea38ca3..c85eaa583a46 100644 --- a/net/wireless/radiotap.c +++ b/net/wireless/radiotap.c @@ -239,14 +239,14 @@ int ieee80211_radiotap_iterator_next( default: if (!iterator->current_namespace || iterator->_arg_index >= iterator->current_namespace->n_bits) { - if (iterator->current_namespace == &radiotap_ns) - return -ENOENT; align = 0; } else { align = iterator->current_namespace->align_size[iterator->_arg_index].align; size = iterator->current_namespace->align_size[iterator->_arg_index].size; } if (!align) { + if (iterator->current_namespace == &radiotap_ns) + return -ENOENT; /* skip all subsequent data */ iterator->_arg = iterator->_next_ns_data; /* give up on this namespace */