Align and clear user buffers

Avoid the bounce buffers a kernel may allocate by using aligned memory,
and clear the memory in case the user's input doesn't fill the entire
buffer.

Signed-off-by: Keith Busch <keith.busch@intel.com>

diff --git a/nvme.c b/nvme.c
index ab469af5de7a2b2d7b7e6781e28c9d5396e7a5c3..6626ed1c221d6111e898efbec5615e49a1f5c280 100644 (file)
--- a/nvme.c
+++ b/nvme.c
@@ -1044,8 +1044,11 @@ static int get_feature(int argc, char **argv)
                break;
        }
        
-       if (cfg.data_len)
-               buf = malloc(cfg.data_len);
+       if (cfg.data_len) {
+               if (posix_memalign(&buf, getpagesize(), cfg.data_len))
+                       exit(ENOMEM);
+               memset(buf, 0, cfg.data_len);
+       }
 
        err = nvme_get_feature(fd, cfg.namespace_id, cfg.feature_id, cfg.sel, cfg.cdw11,
                        cfg.data_len, buf, &result);
@@ -1423,8 +1426,12 @@ static int set_feature(int argc, char **argv)
        }
        if (cfg.feature_id == NVME_FEAT_LBA_RANGE)
                cfg.data_len = 4096;
-       if (cfg.data_len)
-               buf = malloc(cfg.data_len);
+       if (cfg.data_len) {
+               if (posix_memalign(&buf, getpagesize(), cfg.data_len))
+                       exit(ENOMEM);
+               memset(buf, 0, cfg.data_len);
+       }
+
        if (buf) {
                if (strlen(cfg.file)) {
                        ffd = open(cfg.file, O_RDONLY);
@@ -2136,9 +2143,9 @@ static int submit_io(int opcode, char *command, const char *desc,
                return EINVAL;
        }
 
-       buffer = malloc(cfg.data_size);
-       if (!buffer)
+       if (posix_memalign(&buffer, getpagesize(), cfg.data_size))
                return ENOMEM;
+       memset(buffer, 0, cfg.data_size);
 
        if (cfg.metadata_size) {
                mbuffer = malloc(cfg.metadata_size);