diff options
| author | Namjae Jeon <linkinjeon@kernel.org> | 2022-12-31 17:32:31 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-01-12 12:02:56 +0100 |
| commit | 4cd431722018d06076776e2d57331bb010141d8b (patch) | |
| tree | 9d24d12ed31975d73e7a6eadb1a6a68fcb5640ae /fs/ksmbd | |
| parent | 53e9d6851b56626885476a2966194ba994f8bb4b (diff) | |
| download | linux-4cd431722018d06076776e2d57331bb010141d8b.tar.gz | |
ksmbd: fix infinite loop in ksmbd_conn_handler_loop()
commit 83dcedd5540d4ac61376ddff5362f7d9f866a6ec upstream.
If kernel_recvmsg() return -EAGAIN in ksmbd_tcp_readv() and go round
again, It will cause infinite loop issue. And all threads from next
connections would be doing that. This patch add max retry count(2) to
avoid it. kernel_recvmsg() will wait during 7sec timeout and try to
retry two time if -EAGAIN is returned. And add flags of kvmalloc to
__GFP_NOWARN and __GFP_NORETRY to disconnect immediately without
retrying on memory alloation failure.
Fixes: 0626e6641f6b ("cifsd: add server handler for central processing and tranport layers")
Cc: stable@vger.kernel.org
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-18259
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/ksmbd')
| -rw-r--r-- | fs/ksmbd/connection.c | 7 | ||||
| -rw-r--r-- | fs/ksmbd/transport_tcp.c | 5 |
2 files changed, 9 insertions, 3 deletions
diff --git a/fs/ksmbd/connection.c b/fs/ksmbd/connection.c index 12be8386446a..fd0a288af299 100644 --- a/fs/ksmbd/connection.c +++ b/fs/ksmbd/connection.c @@ -316,9 +316,12 @@ int ksmbd_conn_handler_loop(void *p) /* 4 for rfc1002 length field */ size = pdu_size + 4; - conn->request_buf = kvmalloc(size, GFP_KERNEL); + conn->request_buf = kvmalloc(size, + GFP_KERNEL | + __GFP_NOWARN | + __GFP_NORETRY); if (!conn->request_buf) - continue; + break; memcpy(conn->request_buf, hdr_buf, sizeof(hdr_buf)); if (!ksmbd_smb_request(conn)) diff --git a/fs/ksmbd/transport_tcp.c b/fs/ksmbd/transport_tcp.c index 63d55f543bd2..4c6bd0b69979 100644 --- a/fs/ksmbd/transport_tcp.c +++ b/fs/ksmbd/transport_tcp.c @@ -295,6 +295,7 @@ static int ksmbd_tcp_readv(struct tcp_transport *t, struct kvec *iov_orig, struct msghdr ksmbd_msg; struct kvec *iov; struct ksmbd_conn *conn = KSMBD_TRANS(t)->conn; + int max_retry = 2; iov = get_conn_iovec(t, nr_segs); if (!iov) @@ -321,9 +322,11 @@ static int ksmbd_tcp_readv(struct tcp_transport *t, struct kvec *iov_orig, } else if (conn->status == KSMBD_SESS_NEED_RECONNECT) { total_read = -EAGAIN; break; - } else if (length == -ERESTARTSYS || length == -EAGAIN) { + } else if ((length == -ERESTARTSYS || length == -EAGAIN) && + max_retry) { usleep_range(1000, 2000); length = 0; + max_retry--; continue; } else if (length <= 0) { total_read = -EAGAIN; |