From 44b37774f94c6ab87ba0a7f2feaa6e845c2c168c Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Mon, 13 Jan 2020 19:43:40 +0100 Subject: [PATCH] mac80211: fix a page refcounting issue leading to leaks/crashes in rx A-MSDU decap Signed-off-by: Felix Fietkau (cherry-picked from commit 9501469e1146c6d76b7dde6391479314897ba4d8) --- ...-page-refcount-issue-in-A-MSDU-decap.patch | 25 +++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 package/kernel/mac80211/patches/subsys/370-cfg80211-fix-page-refcount-issue-in-A-MSDU-decap.patch diff --git a/package/kernel/mac80211/patches/subsys/370-cfg80211-fix-page-refcount-issue-in-A-MSDU-decap.patch b/package/kernel/mac80211/patches/subsys/370-cfg80211-fix-page-refcount-issue-in-A-MSDU-decap.patch new file mode 100644 index 0000000000..9dba58023d --- /dev/null +++ b/package/kernel/mac80211/patches/subsys/370-cfg80211-fix-page-refcount-issue-in-A-MSDU-decap.patch @@ -0,0 +1,25 @@ +From: Felix Fietkau +Date: Mon, 13 Jan 2020 18:34:31 +0100 +Subject: [PATCH] cfg80211: fix page refcount issue in A-MSDU decap + +The fragments attached to a skb can be part of a compound page. In that case, +page_ref_inc will increment the refcount for the wrong page. Fix this by +using get_page instead, which calls page_ref_inc on the compound head and +also checks for overflow. + +Fixes: 2b67f944f88c ("cfg80211: reuse existing page fragments in A-MSDU rx") +Cc: stable@vger.kernel.org +Signed-off-by: Felix Fietkau +--- + +--- a/net/wireless/util.c ++++ b/net/wireless/util.c +@@ -537,7 +537,7 @@ __frame_add_frag(struct sk_buff *skb, st + struct skb_shared_info *sh = skb_shinfo(skb); + int page_offset; + +- page_ref_inc(page); ++ get_page(page); + page_offset = ptr - page_address(page); + skb_add_rx_frag(skb, sh->nr_frags, page, page_offset, len, size); + } -- 2.30.2