diff options
| author | Eric Dumazet <edumazet@google.com> | 2023-10-09 12:31:10 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-10-10 19:44:44 -0700 |
| commit | 31c07dffafce914c1d1543c135382a11ff058d93 (patch) | |
| tree | a15c17e01991ccee548344146a861e1cbcc80a93 | |
| parent | 5093bbfc10ab6636b32728e35813cbd79feb063c (diff) | |
net: nfc: fix races in nfc_llcp_sock_get() and nfc_llcp_sock_get_sn()
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: 8f50020ed9b8 ("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>
| -rw-r--r-- | net/nfc/llcp_core.c | 30 |
1 files changed, 12 insertions, 18 deletions
diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c index 6705bb895e23..1dac28136e6a 100644 --- a/net/nfc/llcp_core.c +++ b/net/nfc/llcp_core.c @@ -203,17 +203,13 @@ 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; } @@ -346,7 +342,8 @@ 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; @@ -382,6 +379,8 @@ 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; } } @@ -423,7 +422,8 @@ 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; @@ -824,16 +824,7 @@ out: 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) @@ -1298,7 +1289,8 @@ 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; @@ -1318,6 +1310,7 @@ 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; } @@ -1335,6 +1328,7 @@ 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) |