[PATCH 5.16 161/285] net/tls: fix slab-out-of-bounds bug in decrypt_internal

Greg Kroah-Hartman
2022-04-12T08:26:43Z

From: Ziyang Xuan <william.xuanziyang@huawei.com>

[ Upstream commit 9381fe8c849cfbe50245ac01fc077554f6eaa0e2 ]

The memory size of tls_ctx->rx.iv for AES128-CCM is 12 setting in
tls_set_sw_offload(). The return value of crypto_aead_ivsize()
for "ccm(aes)" is 16. So memcpy() require 16 bytes from 12 bytes
memory space will trigger slab-out-of-bounds bug as following:

==================================================================
BUG: KASAN: slab-out-of-bounds in decrypt_internal+0x385/0xc40 [tls]
Read of size 16 at addr ffff888114e84e60 by task tls/10911

Call Trace:
<TASK>
dump_stack_lvl+0x34/0x44
print_report.cold+0x5e/0x5db
? decrypt_internal+0x385/0xc40 [tls]
kasan_report+0xab/0x120
? decrypt_internal+0x385/0xc40 [tls]
kasan_check_range+0xf9/0x1e0
memcpy+0x20/0x60
decrypt_internal+0x385/0xc40 [tls]
? tls_get_rec+0x2e0/0x2e0 [tls]
? process_rx_list+0x1a5/0x420 [tls]
? tls_setup_from_iter.constprop.0+0x2e0/0x2e0 [tls]
decrypt_skb_update+0x9d/0x400 [tls]
tls_sw_recvmsg+0x3c8/0xb50 [tls]

Allocated by task 10911:
kasan_save_stack+0x1e/0x40
__kasan_kmalloc+0x81/0xa0
tls_set_sw_offload+0x2eb/0xa20 [tls]
tls_setsockopt+0x68c/0x700 [tls]
__sys_setsockopt+0xfe/0x1b0

Replace the crypto_aead_ivsize() with prot->iv_size + prot->salt_size
when memcpy() iv value in TLS_1_3_VERSION scenario.

Fixes: f295b3ae9f59 ("net/tls: Add support of AES128-CCM based ciphers")
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/tls/tls_sw.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index dfe623a4e72f..3aecd770ef99 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -1495,7 +1495,7 @@ static int decrypt_internal(struct sock *sk, struct sk_buff *skb,
if (prot->version == TLS_1_3_VERSION ||
prot->cipher_type == TLS_CIPHER_CHACHA20_POLY1305)
memcpy(iv + iv_offset, tls_ctx->rx.iv,
- crypto_aead_ivsize(ctx->aead_recv));
+ prot->iv_size + prot->salt_size);
else
memcpy(iv + iv_offset, tls_ctx->rx.iv, prot->salt_size);

--
2.35.1