Fix crash with absurdly but not impossibly deeply nested device stacks
Use the proper PATH_MAX for the max path for disk util, and use
snprintf() to avoid potentially overwriting it.
Modified by Jens to return NULL instead of exiting.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/diskutil.c b/diskutil.c
index fbc4268..3681dde 100644
--- a/diskutil.c
+++ b/diskutil.c
@@ -276,13 +276,20 @@
{
struct disk_util *du, *__du;
struct flist_head *entry;
+ int l;
dprint(FD_DISKUTIL, "add maj/min %d/%d: %s\n", majdev, mindev, path);
du = smalloc(sizeof(*du));
memset(du, 0, sizeof(*du));
INIT_FLIST_HEAD(&du->list);
- sprintf(du->path, "%s/stat", path);
+ l = snprintf(du->path, sizeof(du->path), "%s/stat", path);
+ if (l < 0 || l >= sizeof(du->path)) {
+ log_err("constructed path \"%.100s[...]/stat\" larger than buffer (%zu bytes)\n",
+ path, sizeof(du->path) - 1);
+ sfree(du);
+ return NULL;
+ }
strncpy((char *) du->dus.name, basename(path), FIO_DU_NAME_SZ);
du->sysfs_root = path;
du->major = majdev;