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| author | Doruk Tan Ozturk <doruk@0sec.ai> | 2026-07-16 21:34:23 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-07-23 08:12:25 -0700 |
| commit | fd3a3f28ed60c6af4b2a39933b151d6b27842c3b (patch) | |
| tree | 4585f5841d936f1a5cb5c39d3161f8388bc7104f /net | |
| parent | 18f116931f52e3c3303ad4b15ff41eb89b0e4239 (diff) | |
| download | linux-next-fd3a3f28ed60c6af4b2a39933b151d6b27842c3b.tar.gz linux-next-fd3a3f28ed60c6af4b2a39933b151d6b27842c3b.zip | |
mac802154: llsec: reject frames shorter than the authentication tag
llsec_do_decrypt_auth() computes the associated-data length for the
AEAD request as
assoclen += datalen - authlen;
where datalen is the number of bytes after the MAC header and authlen
(4, 8 or 16) is the length of the authentication tag. Nothing verifies
that the frame actually carries at least authlen payload bytes. A
secured frame whose payload is shorter than the tag makes
datalen - authlen negative; assoclen is then passed to
aead_request_set_ad() as an unsigned value close to 4 GiB, so
crypto_aead_decrypt() walks far off the end of the scatterlist that
only spans the real frame.
The frame is fully attacker-controlled and reaches this path from any
IEEE 802.15.4 peer in radio range. Reject frames whose payload is
shorter than the authentication tag before the subtraction.
Dynamically reproduced on a KASAN kernel as a general-protection-fault
in the AEAD scatterwalk, and the fix confirmed.
Fixes: 4c14a2fb5d14 ("mac802154: add llsec decryption method")
Cc: stable@vger.kernel.org
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Doruk Tan Ozturk <doruk@0sec.ai>
Link: https://patch.msgid.link/20260716193423.32498-1-doruk@0sec.ai
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/mac802154/llsec.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/net/mac802154/llsec.c b/net/mac802154/llsec.c index 5e7cc11fab3a..85452ef9a58c 100644 --- a/net/mac802154/llsec.c +++ b/net/mac802154/llsec.c @@ -891,6 +891,11 @@ llsec_do_decrypt_auth(struct sk_buff *skb, const struct mac802154_llsec *sec, data = skb_mac_header(skb) + skb->mac_len; datalen = skb_tail_pointer(skb) - data; + if (datalen < authlen) { + kfree_sensitive(req); + return -EBADMSG; + } + sg_init_one(&sg, skb_mac_header(skb), assoclen + datalen); if (!(hdr->sec.level & IEEE802154_SCF_SECLEVEL_ENC)) { |