dlm: dlm_process_incoming_buffer() fixes

* check that length is large enough to cover the non-variable part of message or
  rcom resp. (after checking that it's large enough to cover the header, of
  course).

* kill more pointless casts

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Teigland <teigland@redhat.com>

diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index ec61bba..65499ce 100644 (file)
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -403,6 +403,12 @@ struct dlm_rcom {
        char                    rc_buf[0];
 };
 
+union dlm_packet {
+       struct dlm_header       header;         /* common to other two */
+       struct dlm_message      message;
+       struct dlm_rcom         rcom;
+};
+
 struct rcom_config {
        uint32_t                rf_lvblen;
        uint32_t                rf_lsflags;

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index d9f07a4..2a28048 100644 (file)
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -3822,21 +3822,20 @@ void dlm_receive_message_saved(struct dlm_ls *ls, struct dlm_message *ms)
    standard locking activity) or an RCOM (recovery message sent as part of
    lockspace recovery). */
 
-void dlm_receive_buffer(struct dlm_header *hd, int nodeid)
+void dlm_receive_buffer(union dlm_packet *p, int nodeid)
 {
-       struct dlm_message *ms = (struct dlm_message *) hd;
-       struct dlm_rcom *rc = (struct dlm_rcom *) hd;
+       struct dlm_header *hd = &p->header;
        struct dlm_ls *ls;
        int type = 0;
 
        switch (hd->h_cmd) {
        case DLM_MSG:
-               dlm_message_in(ms);
-               type = ms->m_type;
+               dlm_message_in(&p->message);
+               type = p->message.m_type;
                break;
        case DLM_RCOM:
-               dlm_rcom_in(rc);
-               type = rc->rc_type;
+               dlm_rcom_in(&p->rcom);
+               type = p->rcom.rc_type;
                break;
        default:
                log_print("invalid h_cmd %d from %u", hd->h_cmd, nodeid);
@@ -3856,7 +3855,7 @@ void dlm_receive_buffer(struct dlm_header *hd, int nodeid)
                                  hd->h_lockspace, nodeid, hd->h_cmd, type);
 
                if (hd->h_cmd == DLM_RCOM && type == DLM_RCOM_STATUS)
-                       dlm_send_ls_not_ready(nodeid, rc);
+                       dlm_send_ls_not_ready(nodeid, &p->rcom);
                return;
        }
 
@@ -3865,9 +3864,9 @@ void dlm_receive_buffer(struct dlm_header *hd, int nodeid)
 
        down_read(&ls->ls_recv_active);
        if (hd->h_cmd == DLM_MSG)
-               dlm_receive_message(ls, ms, nodeid);
+               dlm_receive_message(ls, &p->message, nodeid);
        else
-               dlm_receive_rcom(ls, rc, nodeid);
+               dlm_receive_rcom(ls, &p->rcom, nodeid);
        up_read(&ls->ls_recv_active);
 
        dlm_put_lockspace(ls);

diff --git a/fs/dlm/lock.h b/fs/dlm/lock.h
index 27b6ed3..05d9c82 100644 (file)
--- a/fs/dlm/lock.h
+++ b/fs/dlm/lock.h
@@ -17,7 +17,7 @@ void dlm_print_rsb(struct dlm_rsb *r);
 void dlm_dump_rsb(struct dlm_rsb *r);
 void dlm_print_lkb(struct dlm_lkb *lkb);
 void dlm_receive_message_saved(struct dlm_ls *ls, struct dlm_message *ms);
-void dlm_receive_buffer(struct dlm_header *hd, int nodeid);
+void dlm_receive_buffer(union dlm_packet *p, int nodeid);
 int dlm_modes_compat(int mode1, int mode2);
 void dlm_put_rsb(struct dlm_rsb *r);
 void dlm_hold_rsb(struct dlm_rsb *r);

diff --git a/fs/dlm/midcomms.c b/fs/dlm/midcomms.c
index e69926e..07ac709 100644 (file)
--- a/fs/dlm/midcomms.c
+++ b/fs/dlm/midcomms.c
@@ -61,9 +61,9 @@ int dlm_process_incoming_buffer(int nodeid, const void *base,
        union {
                unsigned char __buf[DLM_INBUF_LEN];
                /* this is to force proper alignment on some arches */
-               struct dlm_header dlm;
+               union dlm_packet p;
        } __tmp;
-       struct dlm_header *msg = &__tmp.dlm;
+       union dlm_packet *p = &__tmp.p;
        int ret = 0;
        int err = 0;
        uint16_t msglen;
@@ -75,15 +75,22 @@ int dlm_process_incoming_buffer(int nodeid, const void *base,
                   message may wrap around the end of the buffer back to the
                   start, so we need to use a temp buffer and copy_from_cb. */
 
-               copy_from_cb(msg, base, offset, sizeof(struct dlm_header),
+               copy_from_cb(p, base, offset, sizeof(struct dlm_header),
                             limit);
 
-               msglen = le16_to_cpu(msg->h_length);
-               lockspace = msg->h_lockspace;
+               msglen = le16_to_cpu(p->header.h_length);
+               lockspace = p->header.h_lockspace;
 
                err = -EINVAL;
                if (msglen < sizeof(struct dlm_header))
                        break;
+               if (p->header.h_cmd == DLM_MSG) {
+                       if (msglen < sizeof(struct dlm_message))
+                               break;
+               } else {
+                       if (msglen < sizeof(struct dlm_rcom))
+                               break;
+               }
                err = -E2BIG;
                if (msglen > dlm_config.ci_buffer_size) {
                        log_print("message size %d from %d too big, buf len %d",
@@ -104,26 +111,26 @@ int dlm_process_incoming_buffer(int nodeid, const void *base,
                   in the buffer on the stack (which should work for most
                   ordinary messages). */
 
-               if (msglen > DLM_INBUF_LEN && msg == &__tmp.dlm) {
-                       msg = kmalloc(dlm_config.ci_buffer_size, GFP_KERNEL);
-                       if (msg == NULL)
+               if (msglen > sizeof(__tmp) && p == &__tmp.p) {
+                       p = kmalloc(dlm_config.ci_buffer_size, GFP_KERNEL);
+                       if (p == NULL)
                                return ret;
                }
 
-               copy_from_cb(msg, base, offset, msglen, limit);
+               copy_from_cb(p, base, offset, msglen, limit);
 
-               BUG_ON(lockspace != msg->h_lockspace);
+               BUG_ON(lockspace != p->header.h_lockspace);
 
                ret += msglen;
                offset += msglen;
                offset &= (limit - 1);
                len -= msglen;
 
-               dlm_receive_buffer(msg, nodeid);
+               dlm_receive_buffer(p, nodeid);
        }
 
-       if (msg != &__tmp.dlm)
-               kfree(msg);
+       if (p != &__tmp.p)
+               kfree(p);
 
        return err ? err : ret;
 }