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net: nfc: fix races in nfc_llcp_sock_get() and nfc_llcp_sock_get_sn()

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[ Upstream commit 31c07dffafce914c1d1543c135382a11ff058d93 ]

Sili Luo reported a race in nfc_llcp_sock_get(), leading to UAF.

Getting a reference on the socket found in a lookup while
holding a lock should happen before releasing the lock.

nfc_llcp_sock_get_sn() has a similar problem.

Finally nfc_llcp_recv_snl() needs to make sure the socket
found by nfc_llcp_sock_from_sn() does not disappear.

Fixes: 8f50020ed9 ("NFC: LLCP late binding")
Reported-by: Sili Luo <rootlab@huawei.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willy Tarreau <w@1wt.eu>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20231009123110.3735515-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Eric Dumazet 2023-10-09 12:31:10 +00:00 committed by Greg Kroah-Hartman
parent 22ca282ea0
commit 7adcf014bd
1 changed files with 12 additions and 18 deletions
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30
net/nfc/llcp_core.c
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@ -205,17 +205,13 @@ static struct nfc_llcp_sock *nfc_llcp_sock_get(struct nfc_llcp_local *local,
if (tmp_sock->ssap == ssap && tmp_sock->dsap == dsap) {
llcp_sock = tmp_sock;
sock_hold(&llcp_sock->sk);
break;
}
}
read_unlock(&local->sockets.lock);
if (llcp_sock == NULL)
return NULL;
sock_hold(&llcp_sock->sk);
return llcp_sock;
}
@ -348,7 +344,8 @@ static int nfc_llcp_wks_sap(const char *service_name, size_t service_name_len)
static
struct nfc_llcp_sock *nfc_llcp_sock_from_sn(struct nfc_llcp_local *local,
const u8 *sn, size_t sn_len)
const u8 *sn, size_t sn_len,
bool needref)
{
struct sock *sk;
struct nfc_llcp_sock *llcp_sock, *tmp_sock;
@ -384,6 +381,8 @@ struct nfc_llcp_sock *nfc_llcp_sock_from_sn(struct nfc_llcp_local *local,
if (memcmp(sn, tmp_sock->service_name, sn_len) == 0) {
llcp_sock = tmp_sock;
if (needref)
sock_hold(&llcp_sock->sk);
break;
}
}
@ -425,7 +424,8 @@ u8 nfc_llcp_get_sdp_ssap(struct nfc_llcp_local *local,
* to this service name.
*/
if (nfc_llcp_sock_from_sn(local, sock->service_name,
sock->service_name_len) != NULL) {
sock->service_name_len,
false) != NULL) {
mutex_unlock(&local->sdp_lock);
return LLCP_SAP_MAX;
@ -833,16 +833,7 @@ static struct nfc_llcp_sock *nfc_llcp_connecting_sock_get(struct nfc_llcp_local
static struct nfc_llcp_sock *nfc_llcp_sock_get_sn(struct nfc_llcp_local *local,
const u8 *sn, size_t sn_len)
{
struct nfc_llcp_sock *llcp_sock;
llcp_sock = nfc_llcp_sock_from_sn(local, sn, sn_len);
if (llcp_sock == NULL)
return NULL;
sock_hold(&llcp_sock->sk);
return llcp_sock;
return nfc_llcp_sock_from_sn(local, sn, sn_len, true);
}
static const u8 *nfc_llcp_connect_sn(const struct sk_buff *skb, size_t *sn_len)
@ -1307,7 +1298,8 @@ static void nfc_llcp_recv_snl(struct nfc_llcp_local *local,
}
llcp_sock = nfc_llcp_sock_from_sn(local, service_name,
service_name_len);
service_name_len,
true);
if (!llcp_sock) {
sap = 0;
goto add_snl;
@ -1327,6 +1319,7 @@ static void nfc_llcp_recv_snl(struct nfc_llcp_local *local,
if (sap == LLCP_SAP_MAX) {
sap = 0;
nfc_llcp_sock_put(llcp_sock);
goto add_snl;
}
@ -1344,6 +1337,7 @@ static void nfc_llcp_recv_snl(struct nfc_llcp_local *local,
pr_debug("%p %d\n", llcp_sock, sap);
nfc_llcp_sock_put(llcp_sock);
add_snl:
sdp = nfc_llcp_build_sdres_tlv(tid, sap);
if (sdp == NULL)