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authorDavid Fries <David@Fries.net>2014-04-08 22:37:07 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-04-16 14:07:51 -0700
commit593ceb0c7046c640cf463022189428a45219f595 (patch)
treebda2945990912476effbe15289da3d4072c568d0 /drivers/w1/w1_netlink.c
parenta82cb8b91a37b6015f171a90dc4670e4c8e12e12 (diff)
w1: fix netlink refcnt leak on error path
If the message type is W1_MASTER_CMD or W1_SLAVE_CMD, then a reference is taken when searching for the slave or master device. If there isn't any following data m->len (mlen is a copy) is 0 and packing up the message for later execution is skipped leaving nothing to decrement the reference counts. Way back when, m->len was checked before the search that increments the reference count, but W1_LIST_MASTERS has no additional data, the check was moved in 9be62e0b2fadaf5ff causing this bug. This change reorders to put the check before the reference count is incremented avoiding the problem. Signed-off-by: David Fries <David@Fries.net> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/w1/w1_netlink.c')
-rw-r--r--drivers/w1/w1_netlink.c44
1 files changed, 26 insertions, 18 deletions
diff --git a/drivers/w1/w1_netlink.c b/drivers/w1/w1_netlink.c
index 5234964fe001..a02704a59321 100644
--- a/drivers/w1/w1_netlink.c
+++ b/drivers/w1/w1_netlink.c
@@ -300,12 +300,6 @@ static int w1_process_command_root(struct cn_msg *msg,
struct w1_netlink_msg *w;
u32 *id;
- if (mcmd->type != W1_LIST_MASTERS) {
- printk(KERN_NOTICE "%s: msg: %x.%x, wrong type: %u, len: %u.\n",
- __func__, msg->id.idx, msg->id.val, mcmd->type, mcmd->len);
- return -EPROTO;
- }
-
cn = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!cn)
return -ENOMEM;
@@ -441,6 +435,9 @@ static void w1_process_cb(struct w1_master *dev, struct w1_async_cmd *async_cmd)
w1_netlink_send_error(&node->block->msg, node->m, cmd,
node->block->portid, err);
+ /* ref taken in w1_search_slave or w1_search_master_id when building
+ * the block
+ */
if (sl)
w1_unref_slave(sl);
else
@@ -503,30 +500,42 @@ static void w1_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
msg_len = msg->len;
while (msg_len && !err) {
- struct w1_reg_num id;
- u16 mlen = m->len;
dev = NULL;
sl = NULL;
- memcpy(&id, m->id.id, sizeof(id));
-#if 0
- printk("%s: %02x.%012llx.%02x: type=%02x, len=%u.\n",
- __func__, id.family, (unsigned long long)id.id, id.crc, m->type, m->len);
-#endif
if (m->len + sizeof(struct w1_netlink_msg) > msg_len) {
err = -E2BIG;
break;
}
+ /* execute on this thread, no need to process later */
+ if (m->type == W1_LIST_MASTERS) {
+ err = w1_process_command_root(msg, m, nsp->portid);
+ goto out_cont;
+ }
+
+ /* All following message types require additional data,
+ * check here before references are taken.
+ */
+ if (!m->len) {
+ err = -EPROTO;
+ goto out_cont;
+ }
+
+ /* both search calls take reference counts */
if (m->type == W1_MASTER_CMD) {
dev = w1_search_master_id(m->id.mst.id);
} else if (m->type == W1_SLAVE_CMD) {
- sl = w1_search_slave(&id);
+ sl = w1_search_slave((struct w1_reg_num *)m->id.id);
if (sl)
dev = sl->master;
} else {
- err = w1_process_command_root(msg, m, nsp->portid);
+ printk(KERN_NOTICE
+ "%s: msg: %x.%x, wrong type: %u, len: %u.\n",
+ __func__, msg->id.idx, msg->id.val,
+ m->type, m->len);
+ err = -EPROTO;
goto out_cont;
}
@@ -536,8 +545,6 @@ static void w1_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
}
err = 0;
- if (!mlen)
- goto out_cont;
atomic_inc(&block->refcnt);
node->async.cb = w1_process_cb;
@@ -557,7 +564,8 @@ out_cont:
if (err)
w1_netlink_send_error(msg, m, NULL, nsp->portid, err);
msg_len -= sizeof(struct w1_netlink_msg) + m->len;
- m = (struct w1_netlink_msg *)(((u8 *)m) + sizeof(struct w1_netlink_msg) + m->len);
+ m = (struct w1_netlink_msg *)(((u8 *)m) +
+ sizeof(struct w1_netlink_msg) + m->len);
/*
* Let's allow requests for nonexisting devices.

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