On 05/04/2012 05:54 AM, Stefan Berger wrote:
Error: STRING_NULL: /libvirt/src/node_device/node_device_linux_sysfs.c:80: string_null_argument: Function "saferead" does not terminate string "*buf". /libvirt/src/util/util.c:101: string_null_argument: Function "read" fills array "*buf" with a non-terminated string. /libvirt/src/node_device/node_device_linux_sysfs.c:87: string_null: Passing unterminated string "buf" to a function expecting a null-terminated string.
--- src/node_device/node_device_linux_sysfs.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
Index: libvirt-acl/src/node_device/node_device_linux_sysfs.c =================================================================== --- libvirt-acl.orig/src/node_device/node_device_linux_sysfs.c +++ libvirt-acl/src/node_device/node_device_linux_sysfs.c @@ -69,20 +69,21 @@ out: int read_wwn_linux(int host, const char *file, char **wwn) { char *p = NULL; - int fd = -1, retval = 0; - char buf[64]; + int fd = -1, retval = 0, len; + char buf[65];
Here, I would write: char buf[65] = "";
if (open_wwn_file(LINUX_SYSFS_FC_HOST_PREFIX, host, file, &fd) < 0) { goto out; }
- memset(buf, 0, sizeof(buf));
Then the memset is not necessary (the initialization took care of that instead).
- if (saferead(fd, buf, sizeof(buf)) < 0) { + len = saferead(fd, buf, sizeof(buf) - 1);
You are correct that you need to use sizeof(buf) - 1. But if you guarantee that buf was all NUL on entry, then you don't have to worry about the resulting len,...
+ if (len < 0) { retval = -1; VIR_DEBUG("Failed to read WWN for host%d '%s'", host, file); goto out; } + buf[len] = '\0';
and therefore don't need this trailing assignment. We definitely have an off-by-one bug here, but I don't think we need quite as many changed to fix the issue as what you have here. -- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org