Make use of a few simple helper routines to parse the arguments
rather than sscanf(). This will treat both missing and too-long
arguments as invalid input (rather than silently truncating the
input in the too-long case). In time this can also be used by
rbd_add() to use the passed-in buffer in place, rather than copying
its contents into new buffers.
It appears to me that the sscanf() previously used would not
correctly handle a supplied snapshot--the two final "%s" conversion
specifications were not separated by a space, and I'm not sure
how sscanf() handles that situation. It may not be well-defined.
So that may be a bug this change fixes (but I didn't verify that).
The sizes of the mon_addrs and options buffers are now passed to
rbd_add_parse_args(), so they can be supplied to copy_token().
Signed-off-by: Alex Elder <elder@xxxxxxxxxxxxx>
---
drivers/block/rbd.c | 99
+++++++++++++++++++++++++++++++++++++++++++-------
1 files changed, 85 insertions(+), 14 deletions(-)
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 3731a15..d2157a7 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2220,6 +2220,53 @@ static void rbd_id_put(struct rbd_device *rbd_dev)
}
/*
+ * Skips over white space at *buf, and updates *buf to point to the
+ * first found non-space character (if any). Returns the length of
+ * the token (string of non-white space characters) found.
+ */
+static inline size_t next_token(const char **buf)
+{
+ /*
+ * These are the characters that produce nonzero for
+ * isspace() in the "C" and "POSIX" locales.
+ */
+ const char *spaces = " \f\n\r\t\v";
+
+ *buf += strspn(*buf, spaces); /* Find start of token */
+
+ return strcspn(*buf, spaces); /* Return token length */
+}
+
+/*
+ * Finds the next token in *buf, and if the provided token buffer is
+ * big enough, copies the found token into it. The result, if
+ * copied, is guaranteed to be terminated with '\0'.
+ *
+ * Returns the length of the token found (not including the '\0').
+ * Return value will be 0 if no token is found, and it will be >=
+ * token_size if the token would not fit.
+ *
+ * The *buf pointer will be updated point beyond the end of the
+ * found token. Note that this occurs even if the token buffer is
+ * too small to hold it.
+ */
+static inline size_t copy_token(const char **buf,
+ char *token,
+ size_t token_size)
+{
+ size_t len;
+
+ len = next_token(buf);
+ if (len < token_size) {
+ memcpy(token, *buf, len);
+ *(token + len) = '\0';
+ }
+ *buf += len;
+
+ return len;
+}
+
+/*
* This fills in the pool_name, obj, obj_len, snap_name, obj_len,
* rbd_dev, rbd_md_name, and name fields of the given rbd_dev, based
* on the list of monitor addresses and other options provided via
@@ -2228,25 +2275,48 @@ static void rbd_id_put(struct rbd_device *rbd_dev)
static int rbd_add_parse_args(struct rbd_device *rbd_dev,
const char *buf,
char *mon_addrs,
- char *options)
-{
- if (sscanf(buf, "%" __stringify(RBD_MAX_OPT_LEN) "s "
- "%" __stringify(RBD_MAX_OPT_LEN) "s "
- "%" __stringify(RBD_MAX_POOL_NAME_LEN) "s "
- "%" __stringify(RBD_MAX_OBJ_NAME_LEN) "s"
- "%" __stringify(RBD_MAX_SNAP_NAME_LEN) "s",
- mon_addrs, options, rbd_dev->pool_name,
- rbd_dev->obj, rbd_dev->snap_name) < 4)
+ size_t mon_addrs_size,
+ char *options,
+ size_t options_size)
+{
+ size_t len;
+
+ /* The first four tokens are required */
+
+ len = copy_token(&buf, mon_addrs, mon_addrs_size);
+ if (!len || len >= mon_addrs_size)
return -EINVAL;
- if (rbd_dev->snap_name[0] == 0)
- memcpy(rbd_dev->snap_name, RBD_SNAP_HEAD_NAME,
- sizeof RBD_SNAP_HEAD_NAME);
+ len = copy_token(&buf, options, options_size);
+ if (!len || len >= options_size)
+ return -EINVAL;
+
+ len = copy_token(&buf, rbd_dev->pool_name, sizeof rbd_dev->pool_name);
+ if (!len || len >= sizeof rbd_dev->pool_name)
+ return -EINVAL;
+
+ len = copy_token(&buf, rbd_dev->obj, sizeof rbd_dev->obj);
+ if (!len || len >= sizeof rbd_dev->obj)
+ return -EINVAL;
+
+ /* We have the object length in hand, save it. */
+
+ rbd_dev->obj_len = len;
- rbd_dev->obj_len = strlen(rbd_dev->obj);
snprintf(rbd_dev->obj_md_name, sizeof(rbd_dev->obj_md_name), "%s%s",
rbd_dev->obj, RBD_SUFFIX);
+ /*
+ * The snapshot name is optional, but it's an error if it's
+ * too long. If no snapshot is supplied, fill in the default.
+ */
+ len = copy_token(&buf, rbd_dev->snap_name, sizeof rbd_dev->snap_name);
+ if (!len)
+ memcpy(rbd_dev->snap_name, RBD_SNAP_HEAD_NAME,
+ sizeof RBD_SNAP_HEAD_NAME);
+ else if (len >= sizeof rbd_dev->snap_name)
+ return -EINVAL;
+
return 0;
}
@@ -2285,7 +2355,8 @@ static ssize_t rbd_add(struct bus_type *bus,
snprintf(rbd_dev->name, DEV_NAME_LEN, RBD_DRV_NAME "%d", rbd_dev->id);
/* parse add command */
- rc = rbd_add_parse_args(rbd_dev, buf, mon_addrs, options);
+ rc = rbd_add_parse_args(rbd_dev, buf, mon_addrs, count,
+ options, count);
if (rc)
goto err_put_id;
--
1.7.5.4
--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
