[sheepdog] [PATCH] sheep: fix improper strncmp usage in fill_vdi_info_range()

[Ryusuke Konishi]

The following usage of strncmp in fill_vdi_info_range function is a
misuse.  It is inefficient and also unsafe because it can overrun if
inode->name is not terminated with a null byte due to malformed inode
object:

  strncmp(inode->name, name, strlen(inode->name))

This fixes the issue by replacing the size argument
"strlen(inode->name)" with "sizeof(inode->name)".

Signed-off-by: Ryusuke Konishi <konishi.ryusuke at lab.ntt.co.jp>
---
 sheep/vdi.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sheep/vdi.c b/sheep/vdi.c
index 60bc52d..c8751ed 100644
--- a/sheep/vdi.c
+++ b/sheep/vdi.c
@@ -561,7 +561,7 @@ static int fill_vdi_info_range(uint32_t left, uint32_t right,
 			continue;
 		}
 
-		if (!strncmp(inode->name, name, strlen(inode->name))) {
+		if (!strncmp(inode->name, name, sizeof(inode->name))) {
 			sd_debug("%s = %s, %u = %u", iocb->tag, inode->tag,
 				 iocb->snapid, inode->snap_id);
 			if (vdi_has_tag(iocb)) {
-- 
1.7.9.3