sysfs_unique_holder(): Check read() return value before using as buffer index

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/sysfs.c b/sysfs.c
index a5fcdd03..6c17c5e4 100644
--- a/sysfs.c
+++ b/sysfs.c
@@ -796,6 +796,8 @@ int sysfs_unique_holder(int devnum, long rdev)
 		}
 		n = read(fd, buf, sizeof(buf)-1);
 		close(fd);
+		if (n < 0)
+			continue;
 		buf[n] = 0;
 		if (sscanf(buf, "%d:%d%c", &mj, &mn, &c) != 3 ||
 		    c != '\n') {