[PATCH 1/2] Fix format overflows

[PATCH 1/2] Fix format overflows

[Jonathan Dieter]

The usbip userspace tools call sprintf()/snprintf() and don't check for
the return value which can lead the paths to overflow, truncating the
final file in the path.

More urgently, GCC 7 now warns that these aren't checked with
-Wformat-overflow, and with -Werror enabled in configure.ac, that makes
these tools unbuildable.

This patch fixes these problems by replacing sprintf() with snprintf() in
one place and adding checks for the return value of snprintf().

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>
---
 tools/usb/usbip/libsrc/usbip_common.c      |  8 +++++++-
 tools/usb/usbip/libsrc/usbip_host_common.c | 25 ++++++++++++++++++++-----
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/tools/usb/usbip/libsrc/usbip_common.c b/tools/usb/usbip/libsrc/usbip_common.c
index ac73710..fc875ee 100644
--- a/tools/usb/usbip/libsrc/usbip_common.c
+++ b/tools/usb/usbip/libsrc/usbip_common.c
@@ -215,9 +215,15 @@ int read_usb_interface(struct usbip_usb_device *udev, int i,
 		       struct usbip_usb_interface *uinf)
 {
 	char busid[SYSFS_BUS_ID_SIZE];
+	int size;
 	struct udev_device *sif;
 
-	sprintf(busid, "%s:%d.%d", udev->busid, udev->bConfigurationValue, i);
+	size = snprintf(busid, SYSFS_BUS_ID_SIZE, "%s:%d.%d",
+			udev->busid, udev->bConfigurationValue, i);
+	if (size >= SYSFS_BUS_ID_SIZE) {
+		err("busid length %i >= SYSFS_BUS_ID_SIZE", size);
+		return -1;
+	}
 
 	sif = udev_device_new_from_subsystem_sysname(udev_context, "usb", busid);
 	if (!sif) {
diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c
index 9d41522..690cd49 100644
--- a/tools/usb/usbip/libsrc/usbip_host_common.c
+++ b/tools/usb/usbip/libsrc/usbip_host_common.c
@@ -40,13 +40,19 @@ struct udev *udev_context;
 static int32_t read_attr_usbip_status(struct usbip_usb_device *udev)
 {
 	char status_attr_path[SYSFS_PATH_MAX];
+	int size;
 	int fd;
 	int length;
 	char status;
 	int value = 0;
 
-	snprintf(status_attr_path, SYSFS_PATH_MAX, "%s/usbip_status",
-		 udev->path);
+	size = snprintf(status_attr_path, SYSFS_PATH_MAX, "%s/usbip_status",
+			udev->path);
+	if (size >= SYSFS_PATH_MAX) {
+		err("usbip_status path length %i >= SYSFS_PATH_MAX", size);
+		return -1;
+	}
+
 
 	fd = open(status_attr_path, O_RDONLY);
 	if (fd < 0) {
@@ -218,6 +224,7 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd)
 {
 	char attr_name[] = "usbip_sockfd";
 	char sockfd_attr_path[SYSFS_PATH_MAX];
+	int size;
 	char sockfd_buff[30];
 	int ret;
 
@@ -237,10 +244,18 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd)
 	}
 
 	/* only the first interface is true */
-	snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s",
-		 edev->udev.path, attr_name);
+	size = snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s",
+			edev->udev.path, attr_name);
+	if (size >= SYSFS_PATH_MAX) {
+		err("exported device path length %i >= SYSFS_PATH_MAX", size);
+		return -1;
+	}
 
-	snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd);
+	size = snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd);
+	if (size >= 30) {
+		err("socket length %i >= 30", size);
+		return -1;
+	}
 
 	ret = write_sysfs_attribute(sockfd_attr_path, sockfd_buff,
 				    strlen(sockfd_buff));
-- 
2.9.3

[PATCH 2/2] Fix implicit fallthrough warning

[Jonathan Dieter]

GCC 7 now warns when switch statements fall through implicitly, and with
-Werror enabled in configure.ac, that makes these tools unbuildable.

We fix this by notifying the compiler that this particular case statement
is meant to fall through.

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>
---
 tools/usb/usbip/src/usbip.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/usb/usbip/src/usbip.c b/tools/usb/usbip/src/usbip.c
index d7599d9..73d8eee 100644
--- a/tools/usb/usbip/src/usbip.c
+++ b/tools/usb/usbip/src/usbip.c
@@ -176,6 +176,8 @@ int main(int argc, char *argv[])
 			break;
 		case '?':
 			printf("usbip: invalid option\n");
+			/* Terminate after printing error */
+			/* FALLTHRU */
 		default:
 			usbip_usage();
 			goto out;
-- 
2.9.3

Re: [PATCH 1/2] Fix format overflows

[Krzysztof Opasiak]

Hi,

W dniu 2017-02-20 o 21:51, Jonathan Dieter pisze:
> The usbip userspace tools call sprintf()/snprintf() and don't check for
> the return value which can lead the paths to overflow, truncating the
> final file in the path.
>
> More urgently, GCC 7 now warns that these aren't checked with
> -Wformat-overflow, and with -Werror enabled in configure.ac, that makes
> these tools unbuildable.
>
> This patch fixes these problems by replacing sprintf() with snprintf() in
> one place and adding checks for the return value of snprintf().
>
> Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
> Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>
> ---
>  tools/usb/usbip/libsrc/usbip_common.c      |  8 +++++++-
>  tools/usb/usbip/libsrc/usbip_host_common.c | 25 ++++++++++++++++++++-----
>  2 files changed, 27 insertions(+), 6 deletions(-)
>
> diff --git a/tools/usb/usbip/libsrc/usbip_common.c b/tools/usb/usbip/libsrc/usbip_common.c
> index ac73710..fc875ee 100644
> --- a/tools/usb/usbip/libsrc/usbip_common.c
> +++ b/tools/usb/usbip/libsrc/usbip_common.c
> @@ -215,9 +215,15 @@ int read_usb_interface(struct usbip_usb_device *udev, int i,
>  		       struct usbip_usb_interface *uinf)
>  {
>  	char busid[SYSFS_BUS_ID_SIZE];
> +	int size;
>  	struct udev_device *sif;
>
> -	sprintf(busid, "%s:%d.%d", udev->busid, udev->bConfigurationValue, i);
> +	size = snprintf(busid, SYSFS_BUS_ID_SIZE, "%s:%d.%d",

why not sizeof(busid)?

> +			udev->busid, udev->bConfigurationValue, i);
> +	if (size >= SYSFS_BUS_ID_SIZE) {

As above.

> +		err("busid length %i >= SYSFS_BUS_ID_SIZE", size);
> +		return -1;
> +	}
>
>  	sif = udev_device_new_from_subsystem_sysname(udev_context, "usb", busid);
>  	if (!sif) {
> diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c
> index 9d41522..690cd49 100644
> --- a/tools/usb/usbip/libsrc/usbip_host_common.c
> +++ b/tools/usb/usbip/libsrc/usbip_host_common.c
> @@ -40,13 +40,19 @@ struct udev *udev_context;
>  static int32_t read_attr_usbip_status(struct usbip_usb_device *udev)
>  {
>  	char status_attr_path[SYSFS_PATH_MAX];
> +	int size;
>  	int fd;
>  	int length;
>  	char status;
>  	int value = 0;
>
> -	snprintf(status_attr_path, SYSFS_PATH_MAX, "%s/usbip_status",
> -		 udev->path);
> +	size = snprintf(status_attr_path, SYSFS_PATH_MAX, "%s/usbip_status",

The same here.

> +			udev->path);
> +	if (size >= SYSFS_PATH_MAX) {
> +		err("usbip_status path length %i >= SYSFS_PATH_MAX", size);
> +		return -1;
> +	}
> +
>
>  	fd = open(status_attr_path, O_RDONLY);
>  	if (fd < 0) {
> @@ -218,6 +224,7 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd)
>  {
>  	char attr_name[] = "usbip_sockfd";
>  	char sockfd_attr_path[SYSFS_PATH_MAX];
> +	int size;
>  	char sockfd_buff[30];
>  	int ret;
>
> @@ -237,10 +244,18 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd)
>  	}
>
>  	/* only the first interface is true */
> -	snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s",
> -		 edev->udev.path, attr_name);
> +	size = snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s",
> +			edev->udev.path, attr_name);
> +	if (size >= SYSFS_PATH_MAX) {

hmmm this should be sizeof(sockfd_attr_path) not SYSFS_PATH_MAX

> +		err("exported device path length %i >= SYSFS_PATH_MAX", size);
> +		return -1;
> +	}
>
> -	snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd);
> +	size = snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd);
> +	if (size >= 30) {

Please don't hardcode such values in if. use sizeof() like one line above

> +		err("socket length %i >= 30", size);
> +		return -1;
> +	}
>
>  	ret = write_sysfs_attribute(sockfd_attr_path, sockfd_buff,
>  				    strlen(sockfd_buff));
>

Best regards,
-- 
Krzysztof Opasiak
Samsung R&D Institute Poland
Samsung Electronics

Re: [PATCH 1/2] Fix format overflows

[Jonathan Dieter]

Thanks for looking at this.  One quick question before I put out
version two with your corrections:

On Tue, 2017-02-21 at 07:12 +0100, Krzysztof Opasiak wrote:
> Hi,
> 
> W dniu 2017-02-20 o 21:51, Jonathan Dieter pisze:
> > The usbip userspace tools call sprintf()/snprintf() and don't check
> > for
> > the return value which can lead the paths to overflow, truncating
> > the
> > final file in the path.
> > 
> > More urgently, GCC 7 now warns that these aren't checked with
> > -Wformat-overflow, and with -Werror enabled in configure.ac, that
> > makes
> > these tools unbuildable.
> > 
> > This patch fixes these problems by replacing sprintf() with
> > snprintf() in
> > one place and adding checks for the return value of snprintf().
> > 
> > Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
> > Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>
> > ---
> >  tools/usb/usbip/libsrc/usbip_common.c      |  8 +++++++-
> >  tools/usb/usbip/libsrc/usbip_host_common.c | 25
> > ++++++++++++++++++++-----
> >  2 files changed, 27 insertions(+), 6 deletions(-)
> > 
> > diff --git a/tools/usb/usbip/libsrc/usbip_common.c
> > b/tools/usb/usbip/libsrc/usbip_common.c
> > index ac73710..fc875ee 100644
> > --- a/tools/usb/usbip/libsrc/usbip_common.c
> > +++ b/tools/usb/usbip/libsrc/usbip_common.c
> > @@ -215,9 +215,15 @@ int read_usb_interface(struct usbip_usb_device
> > *udev, int i,
> >  		       struct usbip_usb_interface *uinf)
> >  {
> >  	char busid[SYSFS_BUS_ID_SIZE];
> > +	int size;
> >  	struct udev_device *sif;
> > 
> > -	sprintf(busid, "%s:%d.%d", udev->busid, udev-
> > >bConfigurationValue, i);
> > +	size = snprintf(busid, SYSFS_BUS_ID_SIZE, "%s:%d.%d",
> 
> why not sizeof(busid)?
> 
> > +			udev->busid, udev->bConfigurationValue,
> > i);
> > +	if (size >= SYSFS_BUS_ID_SIZE) {
> 
> As above.
> 
> > +		err("busid length %i >= SYSFS_BUS_ID_SIZE", size);

Should I also change the error messages to use real values?
Ex:
		err("busid length %i >= %i", size, sizeof(busid));

> > +		return -1;
> > +	}
> > 
> >  	sif = udev_device_new_from_subsystem_sysname(udev_context,
> > "usb", busid);
> >  	if (!sif) {
> > diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c
> > b/tools/usb/usbip/libsrc/usbip_host_common.c
> > index 9d41522..690cd49 100644
> > --- a/tools/usb/usbip/libsrc/usbip_host_common.c
> > +++ b/tools/usb/usbip/libsrc/usbip_host_common.c
> > @@ -40,13 +40,19 @@ struct udev *udev_context;
> >  static int32_t read_attr_usbip_status(struct usbip_usb_device
> > *udev)
> >  {
> >  	char status_attr_path[SYSFS_PATH_MAX];
> > +	int size;
> >  	int fd;
> >  	int length;
> >  	char status;
> >  	int value = 0;
> > 
> > -	snprintf(status_attr_path, SYSFS_PATH_MAX,
> > "%s/usbip_status",
> > -		 udev->path);
> > +	size = snprintf(status_attr_path, SYSFS_PATH_MAX,
> > "%s/usbip_status",
> 
> The same here.
> 
> > +			udev->path);
> > +	if (size >= SYSFS_PATH_MAX) {
> > +		err("usbip_status path length %i >=
> > SYSFS_PATH_MAX", size);
> > +		return -1;
> > +	}
> > +
> > 
> >  	fd = open(status_attr_path, O_RDONLY);
> >  	if (fd < 0) {
> > @@ -218,6 +224,7 @@ int usbip_export_device(struct
> > usbip_exported_device *edev, int sockfd)
> >  {
> >  	char attr_name[] = "usbip_sockfd";
> >  	char sockfd_attr_path[SYSFS_PATH_MAX];
> > +	int size;
> >  	char sockfd_buff[30];
> >  	int ret;
> > 
> > @@ -237,10 +244,18 @@ int usbip_export_device(struct
> > usbip_exported_device *edev, int sockfd)
> >  	}
> > 
> >  	/* only the first interface is true */
> > -	snprintf(sockfd_attr_path, sizeof(sockfd_attr_path),
> > "%s/%s",
> > -		 edev->udev.path, attr_name);
> > +	size = snprintf(sockfd_attr_path,
> > sizeof(sockfd_attr_path), "%s/%s",
> > +			edev->udev.path, attr_name);
> > +	if (size >= SYSFS_PATH_MAX) {
> 
> hmmm this should be sizeof(sockfd_attr_path) not SYSFS_PATH_MAX
> 
> > +		err("exported device path length %i >=
> > SYSFS_PATH_MAX", size);
> > +		return -1;
> > +	}
> > 
> > -	snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n",
> > sockfd);
> > +	size = snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n",
> > sockfd);
> > +	if (size >= 30) {
> 
> Please don't hardcode such values in if. use sizeof() like one line
> above
> 
> > +		err("socket length %i >= 30", size);
> > +		return -1;
> > +	}
> > 
> >  	ret = write_sysfs_attribute(sockfd_attr_path, sockfd_buff,
> >  				    strlen(sockfd_buff));
> > 
> 
> Best regards,

Re: [PATCH 1/2] Fix format overflows

[Jonathan Dieter]

On Tue, 2017-02-21 at 08:48 +0200, Jonathan Dieter wrote:
> On Tue, 2017-02-21 at 07:12 +0100, Krzysztof Opasiak wrote:
> > Hi,
> >  
> > W dniu 2017-02-20 o 21:51, Jonathan Dieter pisze: 
> > > +		err("busid length %i >= SYSFS_BUS_ID_SIZE",
> > > size);
> 
> Should I also change the error messages to use real values?
> Ex:
> 		err("busid length %i >= %i", size, sizeof(busid));

On further reflection, I do think changing the error messages to use
sizeof() is cleaner.

If you disagree, please let me know.  I don't have a strong feeling
about it one way or the other.

The next revision uses sizeof() in the places you indicated and changes
size to an unsigned int since we're now comparing it to the result of
sizeof().

Thanks again,
Jonathan

[PATCH v2 1/2] usbip: Fix-format-overflow

[Jonathan Dieter]

The usbip userspace tools call sprintf()/snprintf() and don't check for
the return value which can lead the paths to overflow, truncating the
final file in the path.

More urgently, GCC 7 now warns that these aren't checked with
-Wformat-overflow, and with -Werror enabled in configure.ac, that makes
these tools unbuildable.

This patch fixes these problems by replacing sprintf() with snprintf() in
one place and adding checks for the return value of snprintf().

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>
---
 tools/usb/usbip/libsrc/usbip_common.c      |  8 +++++++-
 tools/usb/usbip/libsrc/usbip_host_common.c | 25 ++++++++++++++++++++-----
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/tools/usb/usbip/libsrc/usbip_common.c b/tools/usb/usbip/libsrc/usbip_common.c
index ac73710..01dd4b2 100644
--- a/tools/usb/usbip/libsrc/usbip_common.c
+++ b/tools/usb/usbip/libsrc/usbip_common.c
@@ -215,9 +215,15 @@ int read_usb_interface(struct usbip_usb_device *udev, int i,
 		       struct usbip_usb_interface *uinf)
 {
 	char busid[SYSFS_BUS_ID_SIZE];
+	unsigned int size;
 	struct udev_device *sif;
 
-	sprintf(busid, "%s:%d.%d", udev->busid, udev->bConfigurationValue, i);
+	size = snprintf(busid, sizeof(busid), "%s:%d.%d",
+			udev->busid, udev->bConfigurationValue, i);
+	if (size >= sizeof(busid)) {
+		err("busid length %u >= %lu", size, sizeof(busid));
+		return -1;
+	}
 
 	sif = udev_device_new_from_subsystem_sysname(udev_context, "usb", busid);
 	if (!sif) {
diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c
index 9d41522..398c1fa 100644
--- a/tools/usb/usbip/libsrc/usbip_host_common.c
+++ b/tools/usb/usbip/libsrc/usbip_host_common.c
@@ -40,13 +40,19 @@ struct udev *udev_context;
 static int32_t read_attr_usbip_status(struct usbip_usb_device *udev)
 {
 	char status_attr_path[SYSFS_PATH_MAX];
+	unsigned int size;
 	int fd;
 	int length;
 	char status;
 	int value = 0;
 
-	snprintf(status_attr_path, SYSFS_PATH_MAX, "%s/usbip_status",
-		 udev->path);
+	size = snprintf(status_attr_path, sizeof(status_attr_path), "%s/usbip_status",
+			udev->path);
+	if (size >= sizeof(status_attr_path)) {
+		err("usbip_status path length %u >= %lu", size, sizeof(status_attr_path));
+		return -1;
+	}
+
 
 	fd = open(status_attr_path, O_RDONLY);
 	if (fd < 0) {
@@ -218,6 +224,7 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd)
 {
 	char attr_name[] = "usbip_sockfd";
 	char sockfd_attr_path[SYSFS_PATH_MAX];
+	unsigned int size;
 	char sockfd_buff[30];
 	int ret;
 
@@ -237,10 +244,18 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd)
 	}
 
 	/* only the first interface is true */
-	snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s",
-		 edev->udev.path, attr_name);
+	size = snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s",
+			edev->udev.path, attr_name);
+	if (size >= sizeof(sockfd_attr_path)) {
+		err("exported device path length %u >= %lu", size, sizeof(sockfd_attr_path));
+		return -1;
+	}
 
-	snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd);
+	size = snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd);
+	if (size >= sizeof(sockfd_buff)) {
+		err("socket length %u >= %lu", size, sizeof(sockfd_buff));
+		return -1;
+	}
 
 	ret = write_sysfs_attribute(sockfd_attr_path, sockfd_buff,
 				    strlen(sockfd_buff));
-- 
2.9.3

[PATCH v2 2/2] usbip: Fix implicit fallthrough warning

[Jonathan Dieter]

GCC 7 now warns when switch statements fall through implicitly, and with
-Werror enabled in configure.ac, that makes these tools unbuildable.

We fix this by notifying the compiler that this particular case statement
is meant to fall through.

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>
---
 tools/usb/usbip/src/usbip.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/usb/usbip/src/usbip.c b/tools/usb/usbip/src/usbip.c
index d7599d9..73d8eee 100644
--- a/tools/usb/usbip/src/usbip.c
+++ b/tools/usb/usbip/src/usbip.c
@@ -176,6 +176,8 @@ int main(int argc, char *argv[])
 			break;
 		case '?':
 			printf("usbip: invalid option\n");
+			/* Terminate after printing error */
+			/* FALLTHRU */
 		default:
 			usbip_usage();
 			goto out;
-- 
2.9.3

Re: [PATCH v2 1/2] usbip: Fix-format-overflow

[Krzysztof Opasiak]

Hi,

W dniu 2017-02-21 o 18:57, Jonathan Dieter pisze:
> The usbip userspace tools call sprintf()/snprintf() and don't check for
> the return value which can lead the paths to overflow, truncating the
> final file in the path.
>
> More urgently, GCC 7 now warns that these aren't checked with
> -Wformat-overflow, and with -Werror enabled in configure.ac, that makes
> these tools unbuildable.
>
> This patch fixes these problems by replacing sprintf() with snprintf() in
> one place and adding checks for the return value of snprintf().
>
> Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
> Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>
> ---
>  tools/usb/usbip/libsrc/usbip_common.c      |  8 +++++++-
>  tools/usb/usbip/libsrc/usbip_host_common.c | 25 ++++++++++++++++++++-----
>  2 files changed, 27 insertions(+), 6 deletions(-)
>
> diff --git a/tools/usb/usbip/libsrc/usbip_common.c b/tools/usb/usbip/libsrc/usbip_common.c
> index ac73710..01dd4b2 100644
> --- a/tools/usb/usbip/libsrc/usbip_common.c
> +++ b/tools/usb/usbip/libsrc/usbip_common.c
> @@ -215,9 +215,15 @@ int read_usb_interface(struct usbip_usb_device *udev, int i,
>  		       struct usbip_usb_interface *uinf)
>  {
>  	char busid[SYSFS_BUS_ID_SIZE];
> +	unsigned int size;

I'm not really convinced to use unsigned here. snprintf() is declared to 
return signed integer so we should assume that some of its 
implementation may return negative error code. Any rationale to this 
instead of just doing a cast for comparsion but signed value to print error?

Best regards
-- 
Krzysztof Opasiak
Samsung R&D Institute Poland
Samsung Electronics

Re: [PATCH v2 1/2] usbip: Fix-format-overflow

[Jonathan Dieter]

On Wed, 2017-02-22 at 06:49 +0100, Krzysztof Opasiak wrote:
> Hi,
> 
> W dniu 2017-02-21 o 18:57, Jonathan Dieter pisze:
<snip>
> >  	char busid[SYSFS_BUS_ID_SIZE];
> > +	unsigned int size;
> 
> I'm not really convinced to use unsigned here. snprintf() is declared
> to 
> return signed integer so we should assume that some of its 
> implementation may return negative error code. Any rationale to this 
> instead of just doing a cast for comparsion but signed value to print
> error?

No, you're absolutely right.  I've fixed this and am sending the next
revision now.

Jonathan

[PATCH v3 1/2] usbip: Fix-format-overflow

[Jonathan Dieter]

The usbip userspace tools call sprintf()/snprintf() and don't check for
the return value which can lead the paths to overflow, truncating the
final file in the path.

More urgently, GCC 7 now warns that these aren't checked with
-Wformat-overflow, and with -Werror enabled in configure.ac, that makes
these tools unbuildable.

This patch fixes these problems by replacing sprintf() with snprintf() in
one place and adding checks for the return value of snprintf().

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>
---
Changes since v2
 * Converted size back to int because snprintf may return < 0 if there's an
   error
 * Expanded error messages to indicate failure may be because size < 0

 tools/usb/usbip/libsrc/usbip_common.c      |  8 +++++++-
 tools/usb/usbip/libsrc/usbip_host_common.c | 28 +++++++++++++++++++++++-----
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/tools/usb/usbip/libsrc/usbip_common.c b/tools/usb/usbip/libsrc/usbip_common.c
index ac73710..66017d7 100644
--- a/tools/usb/usbip/libsrc/usbip_common.c
+++ b/tools/usb/usbip/libsrc/usbip_common.c
@@ -215,9 +215,15 @@ int read_usb_interface(struct usbip_usb_device *udev, int i,
 		       struct usbip_usb_interface *uinf)
 {
 	char busid[SYSFS_BUS_ID_SIZE];
+	int size;
 	struct udev_device *sif;
 
-	sprintf(busid, "%s:%d.%d", udev->busid, udev->bConfigurationValue, i);
+	size = snprintf(busid, sizeof(busid), "%s:%d.%d",
+			udev->busid, udev->bConfigurationValue, i);
+	if (size < 0 || (unsigned int)size >= sizeof(busid)) {
+		err("busid length %i >= %lu or < 0", size, sizeof(busid));
+		return -1;
+	}
 
 	sif = udev_device_new_from_subsystem_sysname(udev_context, "usb", busid);
 	if (!sif) {
diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c
index 9d41522..6fb91d9 100644
--- a/tools/usb/usbip/libsrc/usbip_host_common.c
+++ b/tools/usb/usbip/libsrc/usbip_host_common.c
@@ -40,13 +40,20 @@ struct udev *udev_context;
 static int32_t read_attr_usbip_status(struct usbip_usb_device *udev)
 {
 	char status_attr_path[SYSFS_PATH_MAX];
+	int size;
 	int fd;
 	int length;
 	char status;
 	int value = 0;
 
-	snprintf(status_attr_path, SYSFS_PATH_MAX, "%s/usbip_status",
-		 udev->path);
+	size = snprintf(status_attr_path, sizeof(status_attr_path),
+			"%s/usbip_status", udev->path);
+	if (size < 0 || (unsigned int)size >= sizeof(status_attr_path)) {
+		err("usbip_status path length %i >= %lu or < 0", size,
+		    sizeof(status_attr_path));
+		return -1;
+	}
+
 
 	fd = open(status_attr_path, O_RDONLY);
 	if (fd < 0) {
@@ -218,6 +225,7 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd)
 {
 	char attr_name[] = "usbip_sockfd";
 	char sockfd_attr_path[SYSFS_PATH_MAX];
+	int size;
 	char sockfd_buff[30];
 	int ret;
 
@@ -237,10 +245,20 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd)
 	}
 
 	/* only the first interface is true */
-	snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s",
-		 edev->udev.path, attr_name);
+	size = snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s",
+			edev->udev.path, attr_name);
+	if (size < 0 || (unsigned int)size >= sizeof(sockfd_attr_path)) {
+		err("exported device path length %i >= %lu or < 0", size,
+		    sizeof(sockfd_attr_path));
+		return -1;
+	}
 
-	snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd);
+	size = snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd);
+	if (size < 0 || (unsigned int)size >= sizeof(sockfd_buff)) {
+		err("socket length %i >= %lu or < 0", size,
+		    sizeof(sockfd_buff));
+		return -1;
+	}
 
 	ret = write_sysfs_attribute(sockfd_attr_path, sockfd_buff,
 				    strlen(sockfd_buff));
-- 
2.9.3

[PATCH v3 2/2] usbip: Fix implicit fallthrough warning

[Jonathan Dieter]

GCC 7 now warns when switch statements fall through implicitly, and with
-Werror enabled in configure.ac, that makes these tools unbuildable.

We fix this by notifying the compiler that this particular case statement
is meant to fall through.

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>
---
 tools/usb/usbip/src/usbip.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/usb/usbip/src/usbip.c b/tools/usb/usbip/src/usbip.c
index d7599d9..73d8eee 100644
--- a/tools/usb/usbip/src/usbip.c
+++ b/tools/usb/usbip/src/usbip.c
@@ -176,6 +176,8 @@ int main(int argc, char *argv[])
 			break;
 		case '?':
 			printf("usbip: invalid option\n");
+			/* Terminate after printing error */
+			/* FALLTHRU */
 		default:
 			usbip_usage();
 			goto out;
-- 
2.9.3

[PATCH v4 1/2] usbip: Fix-format-overflow

[Jonathan Dieter]

The usbip userspace tools call sprintf()/snprintf() and don't check for
the return value which can lead the paths to overflow, truncating the
final file in the path.

More urgently, GCC 7 now warns that these aren't checked with
-Wformat-overflow, and with -Werror enabled in configure.ac, that makes
these tools unbuildable.

This patch fixes these problems by replacing sprintf() with snprintf() in
one place and adding checks for the return value of snprintf().

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>
---
Changes since v3
 * Cast sizeof to long unsigned when printing errors to fix building for 32-bit
   architectures

 tools/usb/usbip/libsrc/usbip_common.c      |  9 ++++++++-
 tools/usb/usbip/libsrc/usbip_host_common.c | 28 +++++++++++++++++++++++-----
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/tools/usb/usbip/libsrc/usbip_common.c b/tools/usb/usbip/libsrc/usbip_common.c
index ac73710..1517a23 100644
--- a/tools/usb/usbip/libsrc/usbip_common.c
+++ b/tools/usb/usbip/libsrc/usbip_common.c
@@ -215,9 +215,16 @@ int read_usb_interface(struct usbip_usb_device *udev, int i,
 		       struct usbip_usb_interface *uinf)
 {
 	char busid[SYSFS_BUS_ID_SIZE];
+	int size;
 	struct udev_device *sif;
 
-	sprintf(busid, "%s:%d.%d", udev->busid, udev->bConfigurationValue, i);
+	size = snprintf(busid, sizeof(busid), "%s:%d.%d",
+			udev->busid, udev->bConfigurationValue, i);
+	if (size < 0 || (unsigned int)size >= sizeof(busid)) {
+		err("busid length %i >= %lu or < 0", size,
+		    (long unsigned)sizeof(busid));
+		return -1;
+	}
 
 	sif = udev_device_new_from_subsystem_sysname(udev_context, "usb", busid);
 	if (!sif) {
diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c
index 9d41522..6ff7b60 100644
--- a/tools/usb/usbip/libsrc/usbip_host_common.c
+++ b/tools/usb/usbip/libsrc/usbip_host_common.c
@@ -40,13 +40,20 @@ struct udev *udev_context;
 static int32_t read_attr_usbip_status(struct usbip_usb_device *udev)
 {
 	char status_attr_path[SYSFS_PATH_MAX];
+	int size;
 	int fd;
 	int length;
 	char status;
 	int value = 0;
 
-	snprintf(status_attr_path, SYSFS_PATH_MAX, "%s/usbip_status",
-		 udev->path);
+	size = snprintf(status_attr_path, sizeof(status_attr_path),
+			"%s/usbip_status", udev->path);
+	if (size < 0 || (unsigned int)size >= sizeof(status_attr_path)) {
+		err("usbip_status path length %i >= %lu or < 0", size,
+		    (long unsigned)sizeof(status_attr_path));
+		return -1;
+	}
+
 
 	fd = open(status_attr_path, O_RDONLY);
 	if (fd < 0) {
@@ -218,6 +225,7 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd)
 {
 	char attr_name[] = "usbip_sockfd";
 	char sockfd_attr_path[SYSFS_PATH_MAX];
+	int size;
 	char sockfd_buff[30];
 	int ret;
 
@@ -237,10 +245,20 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd)
 	}
 
 	/* only the first interface is true */
-	snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s",
-		 edev->udev.path, attr_name);
+	size = snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s",
+			edev->udev.path, attr_name);
+	if (size < 0 || (unsigned int)size >= sizeof(sockfd_attr_path)) {
+		err("exported device path length %i >= %lu or < 0", size,
+		    (long unsigned)sizeof(sockfd_attr_path));
+		return -1;
+	}
 
-	snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd);
+	size = snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd);
+	if (size < 0 || (unsigned int)size >= sizeof(sockfd_buff)) {
+		err("socket length %i >= %lu or < 0", size,
+		    (long unsigned)sizeof(sockfd_buff));
+		return -1;
+	}
 
 	ret = write_sysfs_attribute(sockfd_attr_path, sockfd_buff,
 				    strlen(sockfd_buff));
-- 
2.9.3

[PATCH v4 2/2] usbip: Fix implicit fallthrough warning

[Jonathan Dieter]

GCC 7 now warns when switch statements fall through implicitly, and with
-Werror enabled in configure.ac, that makes these tools unbuildable.

We fix this by notifying the compiler that this particular case statement
is meant to fall through.

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>
---
 tools/usb/usbip/src/usbip.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/usb/usbip/src/usbip.c b/tools/usb/usbip/src/usbip.c
index d7599d9..73d8eee 100644
--- a/tools/usb/usbip/src/usbip.c
+++ b/tools/usb/usbip/src/usbip.c
@@ -176,6 +176,8 @@ int main(int argc, char *argv[])
 			break;
 		case '?':
 			printf("usbip: invalid option\n");
+			/* Terminate after printing error */
+			/* FALLTHRU */
 		default:
 			usbip_usage();
 			goto out;
-- 
2.9.3

Re: [PATCH v4 1/2] usbip: Fix-format-overflow

[Jonathan Dieter]

On Mon, 2017-02-27 at 10:31 +0200, Jonathan Dieter wrote:
> The usbip userspace tools call sprintf()/snprintf() and don't check for
> the return value which can lead the paths to overflow, truncating the
> final file in the path.
> 
> More urgently, GCC 7 now warns that these aren't checked with
> -Wformat-overflow, and with -Werror enabled in configure.ac, that makes
> these tools unbuildable.
> 
> This patch fixes these problems by replacing sprintf() with snprintf() in
> one place and adding checks for the return value of snprintf().
> 
> > Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
> > Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>
> ---
> Changes since v3
>  * Cast sizeof to long unsigned when printing errors to fix building for 32-bit
>    architectures

Just wanted to check if there's anything else I need to do to make this
ready?

Thanks,
Jonathan

Re: [PATCH v4 1/2] usbip: Fix-format-overflow

[Shuah Khan]

On 02/27/2017 01:31 AM, Jonathan Dieter wrote:
> The usbip userspace tools call sprintf()/snprintf() and don't check for
> the return value which can lead the paths to overflow, truncating the
> final file in the path.
> 
> More urgently, GCC 7 now warns that these aren't checked with
> -Wformat-overflow, and with -Werror enabled in configure.ac, that makes
> these tools unbuildable.
> 
> This patch fixes these problems by replacing sprintf() with snprintf() in
> one place and adding checks for the return value of snprintf().
> 
> Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
> Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>

Greg,

Please pick this up.

Acked-by: Shuah Khan <shuahkh@osg.samsung.com>

thanks,
-- Shuah

> ---
> Changes since v3
>  * Cast sizeof to long unsigned when printing errors to fix building for 32-bit
>    architectures
> 
>  tools/usb/usbip/libsrc/usbip_common.c      |  9 ++++++++-
>  tools/usb/usbip/libsrc/usbip_host_common.c | 28 +++++++++++++++++++++++-----
>  2 files changed, 31 insertions(+), 6 deletions(-)
> 
> diff --git a/tools/usb/usbip/libsrc/usbip_common.c b/tools/usb/usbip/libsrc/usbip_common.c
> index ac73710..1517a23 100644
> --- a/tools/usb/usbip/libsrc/usbip_common.c
> +++ b/tools/usb/usbip/libsrc/usbip_common.c
> @@ -215,9 +215,16 @@ int read_usb_interface(struct usbip_usb_device *udev, int i,
>  		       struct usbip_usb_interface *uinf)
>  {
>  	char busid[SYSFS_BUS_ID_SIZE];
> +	int size;
>  	struct udev_device *sif;
>  
> -	sprintf(busid, "%s:%d.%d", udev->busid, udev->bConfigurationValue, i);
> +	size = snprintf(busid, sizeof(busid), "%s:%d.%d",
> +			udev->busid, udev->bConfigurationValue, i);
> +	if (size < 0 || (unsigned int)size >= sizeof(busid)) {
> +		err("busid length %i >= %lu or < 0", size,
> +		    (long unsigned)sizeof(busid));
> +		return -1;
> +	}
>  
>  	sif = udev_device_new_from_subsystem_sysname(udev_context, "usb", busid);
>  	if (!sif) {
> diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c
> index 9d41522..6ff7b60 100644
> --- a/tools/usb/usbip/libsrc/usbip_host_common.c
> +++ b/tools/usb/usbip/libsrc/usbip_host_common.c
> @@ -40,13 +40,20 @@ struct udev *udev_context;
>  static int32_t read_attr_usbip_status(struct usbip_usb_device *udev)
>  {
>  	char status_attr_path[SYSFS_PATH_MAX];
> +	int size;
>  	int fd;
>  	int length;
>  	char status;
>  	int value = 0;
>  
> -	snprintf(status_attr_path, SYSFS_PATH_MAX, "%s/usbip_status",
> -		 udev->path);
> +	size = snprintf(status_attr_path, sizeof(status_attr_path),
> +			"%s/usbip_status", udev->path);
> +	if (size < 0 || (unsigned int)size >= sizeof(status_attr_path)) {
> +		err("usbip_status path length %i >= %lu or < 0", size,
> +		    (long unsigned)sizeof(status_attr_path));
> +		return -1;
> +	}
> +
>  
>  	fd = open(status_attr_path, O_RDONLY);
>  	if (fd < 0) {
> @@ -218,6 +225,7 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd)
>  {
>  	char attr_name[] = "usbip_sockfd";
>  	char sockfd_attr_path[SYSFS_PATH_MAX];
> +	int size;
>  	char sockfd_buff[30];
>  	int ret;
>  
> @@ -237,10 +245,20 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd)
>  	}
>  
>  	/* only the first interface is true */
> -	snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s",
> -		 edev->udev.path, attr_name);
> +	size = snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s",
> +			edev->udev.path, attr_name);
> +	if (size < 0 || (unsigned int)size >= sizeof(sockfd_attr_path)) {
> +		err("exported device path length %i >= %lu or < 0", size,
> +		    (long unsigned)sizeof(sockfd_attr_path));
> +		return -1;
> +	}
>  
> -	snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd);
> +	size = snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd);
> +	if (size < 0 || (unsigned int)size >= sizeof(sockfd_buff)) {
> +		err("socket length %i >= %lu or < 0", size,
> +		    (long unsigned)sizeof(sockfd_buff));
> +		return -1;
> +	}
>  
>  	ret = write_sysfs_attribute(sockfd_attr_path, sockfd_buff,
>  				    strlen(sockfd_buff));
> 

Re: [PATCH v4 1/2] usbip: Fix-format-overflow

[Greg Kroah-Hartman]

On Thu, Mar 16, 2017 at 09:04:54AM -0600, Shuah Khan wrote:
> On 02/27/2017 01:31 AM, Jonathan Dieter wrote:
> > The usbip userspace tools call sprintf()/snprintf() and don't check for
> > the return value which can lead the paths to overflow, truncating the
> > final file in the path.
> > 
> > More urgently, GCC 7 now warns that these aren't checked with
> > -Wformat-overflow, and with -Werror enabled in configure.ac, that makes
> > these tools unbuildable.
> > 
> > This patch fixes these problems by replacing sprintf() with snprintf() in
> > one place and adding checks for the return value of snprintf().
> > 
> > Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
> > Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>
> 
> Greg,
> 
> Please pick this up.
> 
> Acked-by: Shuah Khan <shuahkh@osg.samsung.com>

Thanks, still digging through USB patches...