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mac80211: fix a page refcounting issue leading to leaks/crashes in rx A-MSDU decap

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Signed-off-by: Felix Fietkau <nbd@nbd.name>
This commit is contained in:
Felix Fietkau 2020-01-13 19:43:40 +01:00
parent d5b3024139
commit 9501469e11
1 changed files with 25 additions and 0 deletions
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package/kernel/mac80211/patches/subsys/352-cfg80211-fix-page-refcount-issue-in-A-MSDU-decap.patch Normal file
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From: Felix Fietkau <nbd@nbd.name>
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 <nbd@nbd.name>
---
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -564,7 +564,7 @@ __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);
}