diff options
| author | Wei Liu <wei.liu2@citrix.com> | 2014-08-12 11:59:29 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-08-13 20:06:43 -0700 |
| commit | 5c807005fa60deef2db6616d9b7b24fc4c436be9 (patch) | |
| tree | 6e1ca61dc320ede63d38b91def87edeaae31a30c | |
| parent | 490cc7d03c21871eef5949ba77a18b0c7ef70ef5 (diff) | |
xen-netback: fix debugfs write length check
Enlarge buffer size and check input length properly, so that we don't
misuse -ENOSPC.
Note that command like "kickXXXX" is still allowed, that's one patch for
another day if we really want to be very strict on this.
Reported-by: SeeChen Ng <seechen81@gmail.com>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Cc: Zoltan Kiss <zoltan.kiss@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/xen-netback/xenbus.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c index 580517d857bf..4c9041e60e7d 100644 --- a/drivers/net/xen-netback/xenbus.c +++ b/drivers/net/xen-netback/xenbus.c @@ -116,6 +116,7 @@ static int xenvif_read_io_ring(struct seq_file *m, void *v) } #define XENVIF_KICK_STR "kick" +#define BUFFER_SIZE 32 static ssize_t xenvif_write_io_ring(struct file *filp, const char __user *buf, size_t count, @@ -124,22 +125,24 @@ xenvif_write_io_ring(struct file *filp, const char __user *buf, size_t count, struct xenvif_queue *queue = ((struct seq_file *)filp->private_data)->private; int len; - char write[sizeof(XENVIF_KICK_STR)]; + char write[BUFFER_SIZE]; /* don't allow partial writes and check the length */ if (*ppos != 0) return 0; - if (count < sizeof(XENVIF_KICK_STR) - 1) + if (count >= sizeof(write)) return -ENOSPC; len = simple_write_to_buffer(write, - sizeof(write), + sizeof(write) - 1, ppos, buf, count); if (len < 0) return len; + write[len] = '\0'; + if (!strncmp(write, XENVIF_KICK_STR, sizeof(XENVIF_KICK_STR) - 1)) xenvif_interrupt(0, (void *)queue); else { |