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author | Mateusz Jurczyk <mjurczyk@google.com> | 2017-05-24 12:26:20 +0200 |
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committer | Samuel Ortiz <sameo@linux.intel.com> | 2017-06-23 00:26:19 +0200 |
commit | 608c4adfcabab220142ee335a2a003ccd1c0b25b (patch) | |
tree | 02926d53fd24c2cd655fddd70b324e9446cb1430 /net/nfc/netlink.c | |
parent | a81d1ab3cad77e20c2df8baef0a35a4980fc511c (diff) | |
download | linux-608c4adfcabab220142ee335a2a003ccd1c0b25b.tar.bz2 |
nfc: Fix the sockaddr length sanitization in llcp_sock_connect
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>
Diffstat (limited to 'net/nfc/netlink.c')
0 files changed, 0 insertions, 0 deletions