Ensure the copied strings are NUL terminated.
Signed-off-by: Roel Kluin <[email protected]>
---
Documentation/accounting/getdelays.c | 2 +-
Documentation/hwmon/hpfall.c | 2 +-
Documentation/networking/radiotap-headers.txt | 2 +-
.../networking/timestamping/timestamping.c | 4 ++--
4 files changed, 5 insertions(+), 5 deletions(-)
Rationale (please correct me if I'm wrong):
For a larger source string, strncpy only NUL terminates when
the size argument is _less_ than sizeof(destination string).
strlcpy does this when it equals sizeof (dest), but does not
overwrite NULs in the higher chars.
Because cpumask is global I used strncpy, for the extra NULs.
devname is local so I think strlcpy can be used.
For {device,hwtstamp}.ifr_name I thought the strlcpy could
be used since ifr_name is zeroed upon creation of device and
hwtstamp.
Oh, and the parenthesis in radiotap-headers.txt should not
be there.
Roel
diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c
index 6e25c26..4d71b0e 100644
--- a/Documentation/accounting/getdelays.c
+++ b/Documentation/accounting/getdelays.c
@@ -303,7 +303,7 @@ int main(int argc, char *argv[])
err(1, "Invalid rcv buf size\n");
break;
case 'm':
- strncpy(cpumask, optarg, sizeof(cpumask));
+ strncpy(cpumask, optarg, sizeof(cpumask) - 1);
maskset = 1;
printf("cpumask %s maskset %d\n", cpumask, maskset);
break;
diff --git a/Documentation/hwmon/hpfall.c b/Documentation/hwmon/hpfall.c
index 681ec22..00477ea 100644
--- a/Documentation/hwmon/hpfall.c
+++ b/Documentation/hwmon/hpfall.c
@@ -27,7 +27,7 @@ int set_unload_heads_path(char *device)
if (strlen(device) <= 5 || strncmp(device, "/dev/", 5) != 0)
return -EINVAL;
- strncpy(devname, device + 5, sizeof(devname));
+ strlcpy(devname, device + 5, sizeof(devname));
snprintf(unload_heads_path, sizeof(unload_heads_path),
"/sys/block/%s/device/unload_heads", devname);
diff --git a/Documentation/networking/radiotap-headers.txt b/Documentation/networking/radiotap-headers.txt
index 953331c..447e004 100644
--- a/Documentation/networking/radiotap-headers.txt
+++ b/Documentation/networking/radiotap-headers.txt
@@ -126,7 +126,7 @@ int MyFunction(u8 * buf, int buflen)
case IEEE80211_RADIOTAP_ANTENNA:
/* radiotap uses 0 for 1st ant */
- antenna = *iterator.this_arg);
+ antenna = *iterator.this_arg;
break;
case IEEE80211_RADIOTAP_DBM_TX_POWER:
diff --git a/Documentation/networking/timestamping/timestamping.c b/Documentation/networking/timestamping/timestamping.c
index a7936fe..c1acd2c 100644
--- a/Documentation/networking/timestamping/timestamping.c
+++ b/Documentation/networking/timestamping/timestamping.c
@@ -374,12 +374,12 @@ int main(int argc, char **argv)
bail("socket");
memset(&device, 0, sizeof(device));
- strncpy(device.ifr_name, interface, sizeof(device.ifr_name));
+ strlcpy(device.ifr_name, interface, sizeof(device.ifr_name));
if (ioctl(sock, SIOCGIFADDR, &device) < 0)
bail("getting interface IP address");
memset(&hwtstamp, 0, sizeof(hwtstamp));
- strncpy(hwtstamp.ifr_name, interface, sizeof(hwtstamp.ifr_name));
+ strlcpy(hwtstamp.ifr_name, interface, sizeof(hwtstamp.ifr_name));
hwtstamp.ifr_data = (void *)&hwconfig;
memset(&hwconfig, 0, sizeof(hwconfig));
hwconfig.tx_type =
Ensure the copied strings are NUL terminated.
Signed-off-by: Roel Kluin <[email protected]>
---
> Rationale (please correct me if I'm wrong):
>
> For a larger source string, strncpy only NUL terminates when
> the size argument is _less_ than sizeof(destination string).
> strlcpy does this when it equals sizeof (dest), but does not
> overwrite NULs in the higher chars.
>
> Because cpumask is global I used strncpy, for the extra NULs.
> devname is local so I think strlcpy can be used.
> For {device,hwtstamp}.ifr_name I thought the strlcpy could
> be used since ifr_name is zeroed upon creation of device and
> hwtstamp.
>
> Oh, and the parenthesis in radiotap-headers.txt should not
> be there.
See http://markmail.org/message/5ckmbipstgslzolf
(To David Wagner: this was what you meant.)
I forgot strlcpy is not present in old glibc versions,
please use this one instead.
Roel
Documentation/accounting/getdelays.c | 2 +-
Documentation/hwmon/hpfall.c | 2 +-
Documentation/networking/radiotap-headers.txt | 2 +-
.../networking/timestamping/timestamping.c | 4 ++--
4 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c
index 6e25c26..4d71b0e 100644
--- a/Documentation/accounting/getdelays.c
+++ b/Documentation/accounting/getdelays.c
@@ -303,7 +303,7 @@ int main(int argc, char *argv[])
err(1, "Invalid rcv buf size\n");
break;
case 'm':
- strncpy(cpumask, optarg, sizeof(cpumask));
+ strncpy(cpumask, optarg, sizeof(cpumask) - 1);
maskset = 1;
printf("cpumask %s maskset %d\n", cpumask, maskset);
break;
diff --git a/Documentation/hwmon/hpfall.c b/Documentation/hwmon/hpfall.c
index 681ec22..fbcb585 100644
--- a/Documentation/hwmon/hpfall.c
+++ b/Documentation/hwmon/hpfall.c
@@ -27,7 +27,7 @@ int set_unload_heads_path(char *device)
if (strlen(device) <= 5 || strncmp(device, "/dev/", 5) != 0)
return -EINVAL;
- strncpy(devname, device + 5, sizeof(devname));
+ strncpy(devname, device + 5, sizeof(devname) - 1);
snprintf(unload_heads_path, sizeof(unload_heads_path),
"/sys/block/%s/device/unload_heads", devname);
diff --git a/Documentation/networking/radiotap-headers.txt b/Documentation/networking/radiotap-headers.txt
index 953331c..447e004 100644
--- a/Documentation/networking/radiotap-headers.txt
+++ b/Documentation/networking/radiotap-headers.txt
@@ -126,7 +126,7 @@ int MyFunction(u8 * buf, int buflen)
case IEEE80211_RADIOTAP_ANTENNA:
/* radiotap uses 0 for 1st ant */
- antenna = *iterator.this_arg);
+ antenna = *iterator.this_arg;
break;
case IEEE80211_RADIOTAP_DBM_TX_POWER:
diff --git a/Documentation/networking/timestamping/timestamping.c b/Documentation/networking/timestamping/timestamping.c
index a7936fe..bec1f9c 100644
--- a/Documentation/networking/timestamping/timestamping.c
+++ b/Documentation/networking/timestamping/timestamping.c
@@ -374,12 +374,12 @@ int main(int argc, char **argv)
bail("socket");
memset(&device, 0, sizeof(device));
- strncpy(device.ifr_name, interface, sizeof(device.ifr_name));
+ strncpy(device.ifr_name, interface, sizeof(device.ifr_name) - 1);
if (ioctl(sock, SIOCGIFADDR, &device) < 0)
bail("getting interface IP address");
memset(&hwtstamp, 0, sizeof(hwtstamp));
- strncpy(hwtstamp.ifr_name, interface, sizeof(hwtstamp.ifr_name));
+ strncpy(hwtstamp.ifr_name, interface, sizeof(hwtstamp.ifr_name) - 1);
hwtstamp.ifr_data = (void *)&hwconfig;
memset(&hwconfig, 0, sizeof(hwconfig));
hwconfig.tx_type =
Ensure the copied strings are NUL terminated.
Signed-off-by: Roel Kluin <[email protected]>
---
>> Rationale (please correct me if I'm wrong):
I was confused. strncpy requires explicit NUL termination
or it depends on a NUL in the source string.
Documentation/accounting/getdelays.c | 3 ++-
Documentation/hwmon/hpfall.c | 3 ++-
Documentation/networking/radiotap-headers.txt | 2 +-
.../networking/timestamping/timestamping.c | 6 ++++--
4 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c
index 6e25c26..ba54b19 100644
--- a/Documentation/accounting/getdelays.c
+++ b/Documentation/accounting/getdelays.c
@@ -303,7 +303,8 @@ int main(int argc, char *argv[])
err(1, "Invalid rcv buf size\n");
break;
case 'm':
- strncpy(cpumask, optarg, sizeof(cpumask));
+ strncpy(cpumask, optarg, sizeof(cpumask) - 1);
+ cpumask[sizeof(cpumask) - 1] = '\0';
maskset = 1;
printf("cpumask %s maskset %d\n", cpumask, maskset);
break;
diff --git a/Documentation/hwmon/hpfall.c b/Documentation/hwmon/hpfall.c
index 681ec22..4a06c06 100644
--- a/Documentation/hwmon/hpfall.c
+++ b/Documentation/hwmon/hpfall.c
@@ -27,7 +27,8 @@ int set_unload_heads_path(char *device)
if (strlen(device) <= 5 || strncmp(device, "/dev/", 5) != 0)
return -EINVAL;
- strncpy(devname, device + 5, sizeof(devname));
+ strncpy(devname, device + 5, sizeof(devname) - 1);
+ devname[sizeof(devname) - 1] = '\0';
snprintf(unload_heads_path, sizeof(unload_heads_path),
"/sys/block/%s/device/unload_heads", devname);
diff --git a/Documentation/networking/radiotap-headers.txt b/Documentation/networking/radiotap-headers.txt
index 953331c..447e004 100644
--- a/Documentation/networking/radiotap-headers.txt
+++ b/Documentation/networking/radiotap-headers.txt
@@ -126,7 +126,7 @@ int MyFunction(u8 * buf, int buflen)
case IEEE80211_RADIOTAP_ANTENNA:
/* radiotap uses 0 for 1st ant */
- antenna = *iterator.this_arg);
+ antenna = *iterator.this_arg;
break;
case IEEE80211_RADIOTAP_DBM_TX_POWER:
diff --git a/Documentation/networking/timestamping/timestamping.c b/Documentation/networking/timestamping/timestamping.c
index a7936fe..e2a17a4 100644
--- a/Documentation/networking/timestamping/timestamping.c
+++ b/Documentation/networking/timestamping/timestamping.c
@@ -374,12 +374,14 @@ int main(int argc, char **argv)
bail("socket");
memset(&device, 0, sizeof(device));
- strncpy(device.ifr_name, interface, sizeof(device.ifr_name));
+ strncpy(device.ifr_name, interface, sizeof(device.ifr_name) - 1);
+ device.ifr_name[sizeof(device.ifr_name) - 1] = '\0';
if (ioctl(sock, SIOCGIFADDR, &device) < 0)
bail("getting interface IP address");
memset(&hwtstamp, 0, sizeof(hwtstamp));
- strncpy(hwtstamp.ifr_name, interface, sizeof(hwtstamp.ifr_name));
+ strncpy(hwtstamp.ifr_name, interface, sizeof(hwtstamp.ifr_name) - 1);
+ hwtstamp.ifr_name[sizeof(hwtstamp.ifr_name) - 1] = '\0';
hwtstamp.ifr_data = (void *)&hwconfig;
memset(&hwconfig, 0, sizeof(hwconfig));
hwconfig.tx_type =
Roel Kluin wrote:
> Ensure the copied strings are NUL terminated.
>
> Signed-off-by: Roel Kluin <[email protected]>
> ---
>> Rationale (please correct me if I'm wrong):
>
> diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c
> index 6e25c26..4d71b0e 100644
> --- a/Documentation/accounting/getdelays.c
> +++ b/Documentation/accounting/getdelays.c
> @@ -303,7 +303,7 @@ int main(int argc, char *argv[])
> err(1, "Invalid rcv buf size\n");
> break;
> case 'm':
> - strncpy(cpumask, optarg, sizeof(cpumask));
> + strncpy(cpumask, optarg, sizeof(cpumask) - 1);
You need to explicitly NUL terminate strncpy():
http://www.pixelbeat.org/programming/gcc/string_buffers.html
cheers,
P?draig.
On Tue, 17 Nov 2009 12:25:03 GMT, P?draig Brady said:
> You need to explicitly NUL terminate strncpy():
> http://www.pixelbeat.org/programming/gcc/string_buffers.html
Umm. Actually, no. It's *nice* if you explicitly do it. However, it's
not strictly *required*. Consider this code:
struct a {
int b, c;
char d[20];
}
bzero(a,sizeof(a)); /* voila! a->d[19] is now a \0 */
Perfectly valid and we do it all the time. Your referenced web page comments
that using memset() or bzero() is inefficient - I wonder if they actually
*tested* the difference between using one memset() or bzero() on a large
structure compared to lots and lots of explicit initialization statements
(i-cache issues probably most important there). The downside is that there's a
greater chance of some programmer refactoring code and bollixing it up. (The
astute reader will remember a short thread about this not too long ago.. :)
And if you're truly careful and always use the strn- variants of the string
functions, it's actually possible to *not* null-terminate the strings. But
it results in very brittle code and makes Baby Andrew cry, mostly because when
somebody adds a printf() to debug the brittle code, it suddenly becomes even
more brittle... :)