4.19-stable review patch. If anyone has any objections, please let me know.
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From: Konstantin Andreev andreev@swemel.ru
[ Upstream commit e86cac0acdb1a74f608bacefe702f2034133a047 ]
When a process accept()s connection from a unix socket (either stream or seqpacket) it gets the socket with the label of the connecting process.
For example, if a connecting process has a label 'foo', the accept()ed socket will also have 'in' and 'out' labels 'foo', regardless of the label of the listener process.
This is because kernel creates unix child sockets in the context of the connecting process.
I do not see any obvious way for the listener to abuse alien labels coming with the new socket, but, to be on the safe side, it's better fix new socket labels.
Signed-off-by: Konstantin Andreev andreev@swemel.ru Signed-off-by: Casey Schaufler casey@schaufler-ca.com Signed-off-by: Sasha Levin sashal@kernel.org --- security/smack/smack_lsm.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 158f4df39be4..00d8e1b53b2a 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -3745,12 +3745,18 @@ static int smack_unix_stream_connect(struct sock *sock, } }
- /* - * Cross reference the peer labels for SO_PEERSEC. - */ if (rc == 0) { + /* + * Cross reference the peer labels for SO_PEERSEC. + */ nsp->smk_packet = ssp->smk_out; ssp->smk_packet = osp->smk_out; + + /* + * new/child/established socket must inherit listening socket labels + */ + nsp->smk_out = osp->smk_out; + nsp->smk_in = osp->smk_in; }
return rc;