Messages in this thread Patch in this message | | | From | Ziyang Xuan <> | Subject | [PATCH net] net/tls: fix slab-out-of-bounds bug in decrypt_internal | Date | Wed, 30 Mar 2022 16:50:09 +0800 |
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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
Reserve MAX_IV_SIZE memory space for iv to be compatible with all ciphers. And do iv and salt copy like done in tls_do_encryption().
Fixes: f295b3ae9f59 ("net/tls: Add support of AES128-CCM based ciphers") Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com> --- net/tls/tls_sw.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index 0024a692f0f8..6b858f995b23 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -1456,7 +1456,7 @@ static int decrypt_internal(struct sock *sk, struct sk_buff *skb, aead_size = sizeof(*aead_req) + crypto_aead_reqsize(ctx->aead_recv); mem_size = aead_size + (nsg * sizeof(struct scatterlist)); mem_size = mem_size + prot->aad_size; - mem_size = mem_size + crypto_aead_ivsize(ctx->aead_recv); + mem_size = mem_size + MAX_IV_SIZE; /* Allocate a single block of memory which contains * aead_req || sgin[] || sgout[] || aad || iv. @@ -1493,12 +1493,8 @@ static int decrypt_internal(struct sock *sk, struct sk_buff *skb, kfree(mem); return err; } - 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)); - else - memcpy(iv + iv_offset, tls_ctx->rx.iv, prot->salt_size); + memcpy(iv + iv_offset, tls_ctx->rx.iv, + prot->iv_size + prot->salt_size); xor_iv_with_seq(prot, iv + iv_offset, tls_ctx->rx.rec_seq); -- 2.25.1
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