From: Johannes Berg johannes.berg@intel.com

stable inclusion from stable-v4.19.209 commit 3d5d629c99c468458022e9b381789de3595bf4dd category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9R4NV CVE: CVE-2021-47388

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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commit 94513069eb549737bcfc3d988d6ed4da948a2de8 upstream.

When PN checking is done in mac80211, for fragmentation we need to copy the PN to the RX struct so we can later use it to do a comparison, since commit bf30ca922a0c ("mac80211: check defrag PN against current frame").

Unfortunately, in that commit I used the 'hdr' variable without it being necessarily valid, so use-after-free could occur if it was necessary to reallocate (parts of) the frame.

Fix this by reloading the variable after the code that results in the reallocations, if any.

This fixes https://bugzilla.kernel.org/show_bug.cgi?id=214401.

Cc: stable@vger.kernel.org Fixes: bf30ca922a0c ("mac80211: check defrag PN against current frame") Link: https://lore.kernel.org/r/20210927115838.12b9ac6bb233.I1d066acd5408a662c3b6e... Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Li Huafei lihuafei1@huawei.com --- net/mac80211/wpa.c | 6 ++++++ 1 file changed, 6 insertions(+)

diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c index dbeccccf0fdf3..b1d2e2b54f85a 100644 --- a/net/mac80211/wpa.c +++ b/net/mac80211/wpa.c @@ -523,6 +523,9 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx, return RX_DROP_UNUSABLE; }

+ /* reload hdr - skb might have been reallocated */ + hdr = (void *)rx->skb->data; + data_len = skb->len - hdrlen - IEEE80211_CCMP_HDR_LEN - mic_len; if (!rx->sta || data_len < 0) return RX_DROP_UNUSABLE; @@ -752,6 +755,9 @@ ieee80211_crypto_gcmp_decrypt(struct ieee80211_rx_data *rx) return RX_DROP_UNUSABLE; }

+ /* reload hdr - skb might have been reallocated */ + hdr = (void *)rx->skb->data; + data_len = skb->len - hdrlen - IEEE80211_GCMP_HDR_LEN - mic_len; if (!rx->sta || data_len < 0) return RX_DROP_UNUSABLE;