Fix buffer overflow in dsl_dataset_name()

If we're creating a pool with version >= SPA_VERSION_DSL_SCRUB (v11)
we need to account for additional space needed by the origin dataset
which will also be snapshotted: "poolname"+"/"+"$ORIGIN"+"@"+"$ORIGIN".

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #6374

diff --git a/module/zcommon/zfs_namecheck.c b/module/zcommon/zfs_namecheck.c
index f9c20896d46016f66e1fa5d8618a8265a9849b3a..e8db93be7bc9d2293f4325dd07ddcbe8dd82a9ae 100644 (file)
--- a/module/zcommon/zfs_namecheck.c
+++ b/module/zcommon/zfs_namecheck.c
@@ -44,6 +44,7 @@
 #include <string.h>
 #endif
 
+#include <sys/dsl_dir.h>
 #include <sys/param.h>
 #include <sys/nvpair.h>
 #include "zfs_namecheck.h"
@@ -300,8 +301,14 @@ pool_namecheck(const char *pool, namecheck_err_t *why, char *what)
 
        /*
         * Make sure the name is not too long.
+        * If we're creating a pool with version >= SPA_VERSION_DSL_SCRUB (v11)
+        * we need to account for additional space needed by the origin ds which
+        * will also be snapshotted: "poolname"+"/"+"$ORIGIN"+"@"+"$ORIGIN".
+        * Play it safe and enforce this limit even if the pool version is < 11
+        * so it can be upgraded without issues.
         */
-       if (strlen(pool) >= ZFS_MAX_DATASET_NAME_LEN) {
+       if (strlen(pool) >= (ZFS_MAX_DATASET_NAME_LEN - 2 -
+           strlen(ORIGIN_DIR_NAME) * 2)) {
                if (why)
                        *why = NAME_ERR_TOOLONG;
                return (-1);