[PATCH] tools/lib/api/fs/fs.c: Fix misuse of strncpy()

From: Ben Hutchings
Date: Fri Jul 20 2018 - 22:10:50 EST


gcc 8 reports:

In function 'fs__env_override',
inlined from 'fs__get_mountpoint' at fs/fs.c:228:6:
fs/fs.c:222:2: error: 'strncpy' specified bound 4096 equals destination size [-Werror=stringop-truncation]
strncpy(fs->path, override_path, sizeof(fs->path));
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I'm not convinced it makes sense to truncate the copied string here,
but since we're already doing so let's ensure it's still null-
terminated. Use strlcpy() instead.

Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
tools/lib/api/fs/fs.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/tools/lib/api/fs/fs.c
+++ b/tools/lib/api/fs/fs.c
@@ -12,6 +12,7 @@
#include <fcntl.h>
#include <unistd.h>
#include <sys/mount.h>
+#include <linux/string.h>

#include "fs.h"
#include "debug-internal.h"
@@ -219,7 +220,7 @@ static bool fs__env_override(struct fs *
return false;

fs->found = true;
- strncpy(fs->path, override_path, sizeof(fs->path));
+ strlcpy(fs->path, override_path, sizeof(fs->path));
return true;
}

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