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authorAlexander Aring <aahringo@redhat.com>2021-11-02 22:17:20 +0300
committerDavid Teigland <teigland@redhat.com>2021-11-02 22:39:20 +0300
commit9af5b8f0ead7cd90161b0555ed8e85ee38f79fa5 (patch)
treeea127bf5ce24641ae0cf177234319fcf25d14461 /fs/dlm
parent5c16febbc19bb463bfb8e80cb5b24ec6ff1a439f (diff)
downloadlinux-9af5b8f0ead7cd90161b0555ed8e85ee38f79fa5.tar.xz
fs: dlm: add debugfs rawmsg send functionality
This patch adds a dlm functionality to send a raw dlm message to a specific cluster node. This raw message can be build by user space and send out by writing the message to "rawmsg" dlm debugfs file. There is a in progress scapy dlm module which provides a easy build of DLM messages in user space. For example: DLM(h_cmd=3, o_nextcmd=1, h_nodeid=1, h_lockspace=0xe4f48a18, ...) The goal is to provide an easy reproducable state to crash DLM or to fuzz the DLM kernel stack if there are possible ways to crash it. Note: that if the sequence number is zero and dlm version is not set to 3.1 the kernel will automatic will set a right sequence number, otherwise DLM stack testing is not possible. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
Diffstat (limited to 'fs/dlm')
-rw-r--r--fs/dlm/debug_fs.c37
-rw-r--r--fs/dlm/midcomms.c48
-rw-r--r--fs/dlm/midcomms.h2
3 files changed, 87 insertions, 0 deletions
diff --git a/fs/dlm/debug_fs.c b/fs/dlm/debug_fs.c
index 47e9d57e4cae..555904eeea8e 100644
--- a/fs/dlm/debug_fs.c
+++ b/fs/dlm/debug_fs.c
@@ -768,6 +768,42 @@ static int dlm_version_show(struct seq_file *file, void *offset)
}
DEFINE_SHOW_ATTRIBUTE(dlm_version);
+static ssize_t dlm_rawmsg_write(struct file *fp, const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ void *buf;
+ int ret;
+
+ if (count > PAGE_SIZE || count < sizeof(struct dlm_header))
+ return -EINVAL;
+
+ buf = kmalloc(PAGE_SIZE, GFP_NOFS);
+ if (!buf)
+ return -ENOMEM;
+
+ if (copy_from_user(buf, user_buf, count)) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ ret = dlm_midcomms_rawmsg_send(fp->private_data, buf, count);
+ if (ret)
+ goto out;
+
+ kfree(buf);
+ return count;
+
+out:
+ kfree(buf);
+ return ret;
+}
+
+static const struct file_operations dlm_rawmsg_fops = {
+ .open = simple_open,
+ .write = dlm_rawmsg_write,
+ .llseek = no_llseek,
+};
+
void *dlm_create_debug_comms_file(int nodeid, void *data)
{
struct dentry *d_node;
@@ -782,6 +818,7 @@ void *dlm_create_debug_comms_file(int nodeid, void *data)
debugfs_create_file("send_queue_count", 0444, d_node, data,
&dlm_send_queue_cnt_fops);
debugfs_create_file("version", 0444, d_node, data, &dlm_version_fops);
+ debugfs_create_file("rawmsg", 0200, d_node, data, &dlm_rawmsg_fops);
return d_node;
}
diff --git a/fs/dlm/midcomms.c b/fs/dlm/midcomms.c
index 95a5643a950e..0b9bce6f04e1 100644
--- a/fs/dlm/midcomms.c
+++ b/fs/dlm/midcomms.c
@@ -1427,3 +1427,51 @@ int dlm_midcomms_close(int nodeid)
return ret;
}
+
+/* debug functionality to send raw dlm msg from user space */
+struct dlm_rawmsg_data {
+ struct midcomms_node *node;
+ void *buf;
+};
+
+static void midcomms_new_rawmsg_cb(void *data)
+{
+ struct dlm_rawmsg_data *rd = data;
+ struct dlm_header *h = rd->buf;
+
+ switch (h->h_version) {
+ case cpu_to_le32(DLM_VERSION_3_1):
+ break;
+ default:
+ switch (h->h_cmd) {
+ case DLM_OPTS:
+ if (!h->u.h_seq)
+ h->u.h_seq = rd->node->seq_send++;
+ break;
+ default:
+ break;
+ }
+ break;
+ }
+}
+
+int dlm_midcomms_rawmsg_send(struct midcomms_node *node, void *buf,
+ int buflen)
+{
+ struct dlm_rawmsg_data rd;
+ struct dlm_msg *msg;
+ char *msgbuf;
+
+ rd.node = node;
+ rd.buf = buf;
+
+ msg = dlm_lowcomms_new_msg(node->nodeid, buflen, GFP_NOFS,
+ &msgbuf, midcomms_new_rawmsg_cb, &rd);
+ if (!msg)
+ return -ENOMEM;
+
+ memcpy(msgbuf, buf, buflen);
+ dlm_lowcomms_commit_msg(msg);
+ return 0;
+}
+
diff --git a/fs/dlm/midcomms.h b/fs/dlm/midcomms.h
index 579abc6929be..bc63cf73aa87 100644
--- a/fs/dlm/midcomms.h
+++ b/fs/dlm/midcomms.h
@@ -28,6 +28,8 @@ const char *dlm_midcomms_state(struct midcomms_node *node);
unsigned long dlm_midcomms_flags(struct midcomms_node *node);
int dlm_midcomms_send_queue_cnt(struct midcomms_node *node);
uint32_t dlm_midcomms_version(struct midcomms_node *node);
+int dlm_midcomms_rawmsg_send(struct midcomms_node *node, void *buf,
+ int buflen);
#endif /* __MIDCOMMS_DOT_H__ */