diff options
| author | Mateusz Jurczyk <mjurczyk@google.com> | 2017-05-24 12:26:20 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-07-27 15:07:56 -0700 |
| commit | 4a142251a315e4df6f12a7c99a2a6dfe4ac273ec (patch) | |
| tree | 71ad5906d8b198a967c12ce6006639fe66ebcdab | |
| parent | d1ac8a98f312da20784723b53c62ad67766d5cb7 (diff) | |
nfc: Fix the sockaddr length sanitization in llcp_sock_connect
commit 608c4adfcabab220142ee335a2a003ccd1c0b25b upstream.
Fix the sockaddr length verification in the connect() handler of NFC/LLCP
sockets, to compare against the size of the actual structure expected on
input (sockaddr_nfc_llcp) instead of its shorter version (sockaddr_nfc).
Both structures are defined in include/uapi/linux/nfc.h. The fields
specific to the _llcp extended struct are as follows:
276 __u8 dsap; /* Destination SAP, if known */
277 __u8 ssap; /* Source SAP to be bound to */
278 char service_name[NFC_LLCP_MAX_SERVICE_NAME]; /* Service name URI */;
279 size_t service_name_len;
If the caller doesn't provide a sufficiently long sockaddr buffer, these
fields remain uninitialized (and they currently originate from the stack
frame of the top-level sys_connect handler). They are then copied by
llcp_sock_connect() into internal storage (nfc_llcp_sock structure), and
could be subsequently read back through the user-mode getsockname()
function (handled by llcp_sock_getname()). This would result in the
disclosure of up to ~70 uninitialized bytes from the kernel stack to
user-mode clients capable of creating AFC_NFC sockets.
Signed-off-by: Mateusz Jurczyk <mjurczyk@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/nfc/llcp_sock.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/net/nfc/llcp_sock.c b/net/nfc/llcp_sock.c index b9edf5fae6ae..19c2ca1a1548 100644 --- a/net/nfc/llcp_sock.c +++ b/net/nfc/llcp_sock.c @@ -661,8 +661,7 @@ static int llcp_sock_connect(struct socket *sock, struct sockaddr *_addr, pr_debug("sock %p sk %p flags 0x%x\n", sock, sk, flags); - if (!addr || len < sizeof(struct sockaddr_nfc) || - addr->sa_family != AF_NFC) + if (!addr || len < sizeof(*addr) || addr->sa_family != AF_NFC) return -EINVAL; if (addr->service_name_len == 0 && addr->dsap == 0) |