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author | Alexander Aring <aahringo@redhat.com> | 2021-11-02 15:17:20 -0400 |
---|---|---|
committer | David Teigland <teigland@redhat.com> | 2021-11-02 14:39:20 -0500 |
commit | 9af5b8f0ead7cd90161b0555ed8e85ee38f79fa5 (patch) | |
tree | ea127bf5ce24641ae0cf177234319fcf25d14461 /fs/dlm | |
parent | 5c16febbc19bb463bfb8e80cb5b24ec6ff1a439f (diff) | |
download | linux-9af5b8f0ead7cd90161b0555ed8e85ee38f79fa5.tar.gz linux-9af5b8f0ead7cd90161b0555ed8e85ee38f79fa5.tar.bz2 linux-9af5b8f0ead7cd90161b0555ed8e85ee38f79fa5.zip |
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.c | 37 | ||||
-rw-r--r-- | fs/dlm/midcomms.c | 48 | ||||
-rw-r--r-- | fs/dlm/midcomms.h | 2 |
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__ */ |