Re: [PATCH 1/3] tools/hv: Fix for long file names from readdir
On Tue, Dec 18, 2012 at 12:38:03PM +, Ben Hutchings wrote: > On Tue, 2012-12-18 at 03:06 -0500, Tomas Hozza wrote: > > - Original Message - > > > > This is just for sanity. The value PATH_MAX was chosen after > > > > discussion > > > > with K. Y. Srinivasan and Olaf Hering instead of some "magic" > > > > number like > > > > 256 or 512. > > > > > > PATH_MAX is a magic name. > > > > It is defined in "limits.h". I would welcome some more constructive > > argumentation and critics. > > It still bears no relation to any actual limit in the C library or Linux > kernel. So it's no more valid than the previous number. > > In the current context we're enumerating /sys/class/net and we know that > all the interface names in there are limited to IFNAMSIZ-1 = 15 (there > is also potentially "bonding_masters"). The longest path name we need > to use is definitely much shorter than even 256 bytes. > > > > > > Using snprintf() is a good idea, but you need to check the return > > > > > value and handle the truncation case somehow. > > > > > > > > By using PATH_MAX sized buffer there is no need for handling the > > > > truncation > > > > case. > > > > > > You are claiming two contradictory things: sprintf() may overrun the > > > buffer, so we need the length check provided by snprintf(), but there > > > is no need to check for truncation because we know the length is > > > sufficient. > > > > So what do you propose? How should it be solved? > > if (snprintf(dev_id, sizeof(dev_id), ...) >= sizeof(dev_id)) > continue; > > Possibly logging a warning. I agree, I'm dropping this patch from my to-apply queue. greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/3] tools/hv: Fix for long file names from readdir
On Tue, Dec 18, 2012 at 12:38:03PM +, Ben Hutchings wrote: On Tue, 2012-12-18 at 03:06 -0500, Tomas Hozza wrote: - Original Message - This is just for sanity. The value PATH_MAX was chosen after discussion with K. Y. Srinivasan and Olaf Hering instead of some magic number like 256 or 512. PATH_MAX is a magic name. It is defined in limits.h. I would welcome some more constructive argumentation and critics. It still bears no relation to any actual limit in the C library or Linux kernel. So it's no more valid than the previous number. In the current context we're enumerating /sys/class/net and we know that all the interface names in there are limited to IFNAMSIZ-1 = 15 (there is also potentially bonding_masters). The longest path name we need to use is definitely much shorter than even 256 bytes. Using snprintf() is a good idea, but you need to check the return value and handle the truncation case somehow. By using PATH_MAX sized buffer there is no need for handling the truncation case. You are claiming two contradictory things: sprintf() may overrun the buffer, so we need the length check provided by snprintf(), but there is no need to check for truncation because we know the length is sufficient. So what do you propose? How should it be solved? if (snprintf(dev_id, sizeof(dev_id), ...) = sizeof(dev_id)) continue; Possibly logging a warning. I agree, I'm dropping this patch from my to-apply queue. greg k-h -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/3] tools/hv: Fix for long file names from readdir
On Tue, 2012-12-18 at 03:06 -0500, Tomas Hozza wrote: > - Original Message - > > > This is just for sanity. The value PATH_MAX was chosen after > > > discussion > > > with K. Y. Srinivasan and Olaf Hering instead of some "magic" > > > number like > > > 256 or 512. > > > > PATH_MAX is a magic name. > > It is defined in "limits.h". I would welcome some more constructive > argumentation and critics. It still bears no relation to any actual limit in the C library or Linux kernel. So it's no more valid than the previous number. In the current context we're enumerating /sys/class/net and we know that all the interface names in there are limited to IFNAMSIZ-1 = 15 (there is also potentially "bonding_masters"). The longest path name we need to use is definitely much shorter than even 256 bytes. > > > > Using snprintf() is a good idea, but you need to check the return > > > > value and handle the truncation case somehow. > > > > > > By using PATH_MAX sized buffer there is no need for handling the > > > truncation > > > case. > > > > You are claiming two contradictory things: sprintf() may overrun the > > buffer, so we need the length check provided by snprintf(), but there > > is no need to check for truncation because we know the length is > > sufficient. > > So what do you propose? How should it be solved? if (snprintf(dev_id, sizeof(dev_id), ...) >= sizeof(dev_id)) continue; Possibly logging a warning. Ben. -- Ben Hutchings Life is like a sewer: what you get out of it depends on what you put into it. signature.asc Description: This is a digitally signed message part
Re: [PATCH 1/3] tools/hv: Fix for long file names from readdir
- Original Message - > > This is just for sanity. The value PATH_MAX was chosen after > > discussion > > with K. Y. Srinivasan and Olaf Hering instead of some "magic" > > number like > > 256 or 512. > > PATH_MAX is a magic name. It is defined in "limits.h". I would welcome some more constructive argumentation and critics. > > > Using snprintf() is a good idea, but you need to check the return > > > value and handle the truncation case somehow. > > > > By using PATH_MAX sized buffer there is no need for handling the > > truncation > > case. > > You are claiming two contradictory things: sprintf() may overrun the > buffer, so we need the length check provided by snprintf(), but there > is no need to check for truncation because we know the length is > sufficient. So what do you propose? How should it be solved? Thank you. Regards, Tomas Hozza -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/3] tools/hv: Fix for long file names from readdir
- Original Message - This is just for sanity. The value PATH_MAX was chosen after discussion with K. Y. Srinivasan and Olaf Hering instead of some magic number like 256 or 512. PATH_MAX is a magic name. It is defined in limits.h. I would welcome some more constructive argumentation and critics. Using snprintf() is a good idea, but you need to check the return value and handle the truncation case somehow. By using PATH_MAX sized buffer there is no need for handling the truncation case. You are claiming two contradictory things: sprintf() may overrun the buffer, so we need the length check provided by snprintf(), but there is no need to check for truncation because we know the length is sufficient. So what do you propose? How should it be solved? Thank you. Regards, Tomas Hozza -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/3] tools/hv: Fix for long file names from readdir
On Tue, 2012-12-18 at 03:06 -0500, Tomas Hozza wrote: - Original Message - This is just for sanity. The value PATH_MAX was chosen after discussion with K. Y. Srinivasan and Olaf Hering instead of some magic number like 256 or 512. PATH_MAX is a magic name. It is defined in limits.h. I would welcome some more constructive argumentation and critics. It still bears no relation to any actual limit in the C library or Linux kernel. So it's no more valid than the previous number. In the current context we're enumerating /sys/class/net and we know that all the interface names in there are limited to IFNAMSIZ-1 = 15 (there is also potentially bonding_masters). The longest path name we need to use is definitely much shorter than even 256 bytes. Using snprintf() is a good idea, but you need to check the return value and handle the truncation case somehow. By using PATH_MAX sized buffer there is no need for handling the truncation case. You are claiming two contradictory things: sprintf() may overrun the buffer, so we need the length check provided by snprintf(), but there is no need to check for truncation because we know the length is sufficient. So what do you propose? How should it be solved? if (snprintf(dev_id, sizeof(dev_id), ...) = sizeof(dev_id)) continue; Possibly logging a warning. Ben. -- Ben Hutchings Life is like a sewer: what you get out of it depends on what you put into it. signature.asc Description: This is a digitally signed message part
Re: [PATCH 1/3] tools/hv: Fix for long file names from readdir
On Tue, Nov 27, 2012 at 03:28:25PM -0500, Tomas Hozza wrote: > > > - Original Message - > > On Tue, 2012-11-27 at 08:56 +0100, Tomas Hozza wrote: > > > kvp_get_if_name and kvp_mac_to_if_name copy strings into statically > > > sized buffers which could be too small to store really long names. > > > > > > Buffer sizes have been changed to PATH_MAX, include "limits.h" > > > where > > > PATH_MAX is defined was added and length checks ware added via > > > snprintf. > > [...] > > > > PATH_MAX has nothing to do with any actual kernel limit; it's no more > > meaningful than the current value of 256. Network interface names > > are > > limited to 15 characters, thus the current array is more than long > > enough. So I think this is entirely unnecessary. > > This is just for sanity. The value PATH_MAX was chosen after discussion > with K. Y. Srinivasan and Olaf Hering instead of some "magic" number like > 256 or 512. PATH_MAX is a magic name. > > Using snprintf() is a good idea, but you need to check the return > > value and handle the truncation case somehow. > > By using PATH_MAX sized buffer there is no need for handling the truncation > case. You are claiming two contradictory things: sprintf() may overrun the buffer, so we need the length check provided by snprintf(), but there is no need to check for truncation because we know the length is sufficient. Ben. -- Ben Hutchings We get into the habit of living before acquiring the habit of thinking. - Albert Camus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/3] tools/hv: Fix for long file names from readdir
- Original Message - > On Tue, 2012-11-27 at 08:56 +0100, Tomas Hozza wrote: > > kvp_get_if_name and kvp_mac_to_if_name copy strings into statically > > sized buffers which could be too small to store really long names. > > > > Buffer sizes have been changed to PATH_MAX, include "limits.h" > > where > > PATH_MAX is defined was added and length checks ware added via > > snprintf. > [...] > > PATH_MAX has nothing to do with any actual kernel limit; it's no more > meaningful than the current value of 256. Network interface names > are > limited to 15 characters, thus the current array is more than long > enough. So I think this is entirely unnecessary. This is just for sanity. The value PATH_MAX was chosen after discussion with K. Y. Srinivasan and Olaf Hering instead of some "magic" number like 256 or 512. > Using snprintf() is a good idea, but you need to check the return > value and handle the truncation case somehow. By using PATH_MAX sized buffer there is no need for handling the truncation case. Tomas Hozza -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/3] tools/hv: Fix for long file names from readdir
On Tue, 2012-11-27 at 08:56 +0100, Tomas Hozza wrote: > kvp_get_if_name and kvp_mac_to_if_name copy strings into statically > sized buffers which could be too small to store really long names. > > Buffer sizes have been changed to PATH_MAX, include "limits.h" where > PATH_MAX is defined was added and length checks ware added via snprintf. [...] PATH_MAX has nothing to do with any actual kernel limit; it's no more meaningful than the current value of 256. Network interface names are limited to 15 characters, thus the current array is more than long enough. So I think this is entirely unnecessary. Using snprintf() is a good idea, but you need to check the return value and handle the truncation case somehow. Ben. -- Ben Hutchings Never attribute to conspiracy what can adequately be explained by stupidity. signature.asc Description: This is a digitally signed message part
RE: [PATCH 1/3] tools/hv: Fix for long file names from readdir
> -Original Message-
> From: Tomas Hozza [mailto:tho...@redhat.com]
> Sent: Tuesday, November 27, 2012 2:57 AM
> To: gre...@linuxfoundation.org; linux-kernel@vger.kernel.org;
> de...@linuxdriverproject.org; o...@aepfle.de; a...@canonical.com;
> jasow...@redhat.com; KY Srinivasan; b...@decadent.org.uk
> Cc: Tomas Hozza
> Subject: [PATCH 1/3] tools/hv: Fix for long file names from readdir
>
> kvp_get_if_name and kvp_mac_to_if_name copy strings into statically
> sized buffers which could be too small to store really long names.
>
> Buffer sizes have been changed to PATH_MAX, include "limits.h" where
> PATH_MAX is defined was added and length checks ware added via snprintf.
>
> Signed-off-by: Tomas Hozza
Acked-by: K. Y. Srinivasan
> ---
> tools/hv/hv_kvp_daemon.c | 26 +-
> 1 file changed, 9 insertions(+), 17 deletions(-)
>
> diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
> index d25a469..90f1f07 100644
> --- a/tools/hv/hv_kvp_daemon.c
> +++ b/tools/hv/hv_kvp_daemon.c
> @@ -44,6 +44,7 @@
> #include
> #include
> #include
> +#include
>
> /*
> * KVP protocol: The user mode component first registers with the
> @@ -592,26 +593,22 @@ static char *kvp_get_if_name(char *guid)
> DIR *dir;
> struct dirent *entry;
> FILE*file;
> - char*p, *q, *x;
> + char*p, *x;
> char*if_name = NULL;
> charbuf[256];
> char *kvp_net_dir = "/sys/class/net/";
> - char dev_id[256];
> + char dev_id[PATH_MAX];
>
> dir = opendir(kvp_net_dir);
> if (dir == NULL)
> return NULL;
>
> - snprintf(dev_id, sizeof(dev_id), "%s", kvp_net_dir);
> - q = dev_id + strlen(kvp_net_dir);
> -
> while ((entry = readdir(dir)) != NULL) {
> /*
>* Set the state for the next pass.
>*/
> - *q = '\0';
> - strcat(dev_id, entry->d_name);
> - strcat(dev_id, "/device/device_id");
> + snprintf(dev_id, sizeof(dev_id), "%s%s/device/device_id",
> kvp_net_dir,
> + entry->d_name);
>
> file = fopen(dev_id, "r");
> if (file == NULL)
> @@ -684,28 +681,23 @@ static char *kvp_mac_to_if_name(char *mac)
> DIR *dir;
> struct dirent *entry;
> FILE*file;
> - char*p, *q, *x;
> + char*p, *x;
> char*if_name = NULL;
> charbuf[256];
> char *kvp_net_dir = "/sys/class/net/";
> - char dev_id[256];
> + char dev_id[PATH_MAX];
> int i;
>
> dir = opendir(kvp_net_dir);
> if (dir == NULL)
> return NULL;
>
> - snprintf(dev_id, sizeof(dev_id), kvp_net_dir);
> - q = dev_id + strlen(kvp_net_dir);
> -
> while ((entry = readdir(dir)) != NULL) {
> /*
>* Set the state for the next pass.
>*/
> - *q = '\0';
> -
> - strcat(dev_id, entry->d_name);
> - strcat(dev_id, "/address");
> + snprintf(dev_id, sizeof(dev_id), "%s%s/address", kvp_net_dir,
> +entry->d_name);
>
> file = fopen(dev_id, "r");
> if (file == NULL)
> --
> 1.7.11.7
>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
RE: [PATCH 1/3] tools/hv: Fix for long file names from readdir
-Original Message-
From: Tomas Hozza [mailto:tho...@redhat.com]
Sent: Tuesday, November 27, 2012 2:57 AM
To: gre...@linuxfoundation.org; linux-kernel@vger.kernel.org;
de...@linuxdriverproject.org; o...@aepfle.de; a...@canonical.com;
jasow...@redhat.com; KY Srinivasan; b...@decadent.org.uk
Cc: Tomas Hozza
Subject: [PATCH 1/3] tools/hv: Fix for long file names from readdir
kvp_get_if_name and kvp_mac_to_if_name copy strings into statically
sized buffers which could be too small to store really long names.
Buffer sizes have been changed to PATH_MAX, include limits.h where
PATH_MAX is defined was added and length checks ware added via snprintf.
Signed-off-by: Tomas Hozza tho...@redhat.com
Acked-by: K. Y. Srinivasan k...@microsoft.com
---
tools/hv/hv_kvp_daemon.c | 26 +-
1 file changed, 9 insertions(+), 17 deletions(-)
diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
index d25a469..90f1f07 100644
--- a/tools/hv/hv_kvp_daemon.c
+++ b/tools/hv/hv_kvp_daemon.c
@@ -44,6 +44,7 @@
#include fcntl.h
#include dirent.h
#include net/if.h
+#include limits.h
/*
* KVP protocol: The user mode component first registers with the
@@ -592,26 +593,22 @@ static char *kvp_get_if_name(char *guid)
DIR *dir;
struct dirent *entry;
FILE*file;
- char*p, *q, *x;
+ char*p, *x;
char*if_name = NULL;
charbuf[256];
char *kvp_net_dir = /sys/class/net/;
- char dev_id[256];
+ char dev_id[PATH_MAX];
dir = opendir(kvp_net_dir);
if (dir == NULL)
return NULL;
- snprintf(dev_id, sizeof(dev_id), %s, kvp_net_dir);
- q = dev_id + strlen(kvp_net_dir);
-
while ((entry = readdir(dir)) != NULL) {
/*
* Set the state for the next pass.
*/
- *q = '\0';
- strcat(dev_id, entry-d_name);
- strcat(dev_id, /device/device_id);
+ snprintf(dev_id, sizeof(dev_id), %s%s/device/device_id,
kvp_net_dir,
+ entry-d_name);
file = fopen(dev_id, r);
if (file == NULL)
@@ -684,28 +681,23 @@ static char *kvp_mac_to_if_name(char *mac)
DIR *dir;
struct dirent *entry;
FILE*file;
- char*p, *q, *x;
+ char*p, *x;
char*if_name = NULL;
charbuf[256];
char *kvp_net_dir = /sys/class/net/;
- char dev_id[256];
+ char dev_id[PATH_MAX];
int i;
dir = opendir(kvp_net_dir);
if (dir == NULL)
return NULL;
- snprintf(dev_id, sizeof(dev_id), kvp_net_dir);
- q = dev_id + strlen(kvp_net_dir);
-
while ((entry = readdir(dir)) != NULL) {
/*
* Set the state for the next pass.
*/
- *q = '\0';
-
- strcat(dev_id, entry-d_name);
- strcat(dev_id, /address);
+ snprintf(dev_id, sizeof(dev_id), %s%s/address, kvp_net_dir,
+entry-d_name);
file = fopen(dev_id, r);
if (file == NULL)
--
1.7.11.7
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/3] tools/hv: Fix for long file names from readdir
On Tue, 2012-11-27 at 08:56 +0100, Tomas Hozza wrote: kvp_get_if_name and kvp_mac_to_if_name copy strings into statically sized buffers which could be too small to store really long names. Buffer sizes have been changed to PATH_MAX, include limits.h where PATH_MAX is defined was added and length checks ware added via snprintf. [...] PATH_MAX has nothing to do with any actual kernel limit; it's no more meaningful than the current value of 256. Network interface names are limited to 15 characters, thus the current array is more than long enough. So I think this is entirely unnecessary. Using snprintf() is a good idea, but you need to check the return value and handle the truncation case somehow. Ben. -- Ben Hutchings Never attribute to conspiracy what can adequately be explained by stupidity. signature.asc Description: This is a digitally signed message part
Re: [PATCH 1/3] tools/hv: Fix for long file names from readdir
- Original Message - On Tue, 2012-11-27 at 08:56 +0100, Tomas Hozza wrote: kvp_get_if_name and kvp_mac_to_if_name copy strings into statically sized buffers which could be too small to store really long names. Buffer sizes have been changed to PATH_MAX, include limits.h where PATH_MAX is defined was added and length checks ware added via snprintf. [...] PATH_MAX has nothing to do with any actual kernel limit; it's no more meaningful than the current value of 256. Network interface names are limited to 15 characters, thus the current array is more than long enough. So I think this is entirely unnecessary. This is just for sanity. The value PATH_MAX was chosen after discussion with K. Y. Srinivasan and Olaf Hering instead of some magic number like 256 or 512. Using snprintf() is a good idea, but you need to check the return value and handle the truncation case somehow. By using PATH_MAX sized buffer there is no need for handling the truncation case. Tomas Hozza -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/3] tools/hv: Fix for long file names from readdir
On Tue, Nov 27, 2012 at 03:28:25PM -0500, Tomas Hozza wrote: - Original Message - On Tue, 2012-11-27 at 08:56 +0100, Tomas Hozza wrote: kvp_get_if_name and kvp_mac_to_if_name copy strings into statically sized buffers which could be too small to store really long names. Buffer sizes have been changed to PATH_MAX, include limits.h where PATH_MAX is defined was added and length checks ware added via snprintf. [...] PATH_MAX has nothing to do with any actual kernel limit; it's no more meaningful than the current value of 256. Network interface names are limited to 15 characters, thus the current array is more than long enough. So I think this is entirely unnecessary. This is just for sanity. The value PATH_MAX was chosen after discussion with K. Y. Srinivasan and Olaf Hering instead of some magic number like 256 or 512. PATH_MAX is a magic name. Using snprintf() is a good idea, but you need to check the return value and handle the truncation case somehow. By using PATH_MAX sized buffer there is no need for handling the truncation case. You are claiming two contradictory things: sprintf() may overrun the buffer, so we need the length check provided by snprintf(), but there is no need to check for truncation because we know the length is sufficient. Ben. -- Ben Hutchings We get into the habit of living before acquiring the habit of thinking. - Albert Camus -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 1/3] tools/hv: Fix for long file names from readdir
kvp_get_if_name and kvp_mac_to_if_name copy strings into statically
sized buffers which could be too small to store really long names.
Buffer sizes have been changed to PATH_MAX, include "limits.h" where
PATH_MAX is defined was added and length checks ware added via snprintf.
Signed-off-by: Tomas Hozza
---
tools/hv/hv_kvp_daemon.c | 26 +-
1 file changed, 9 insertions(+), 17 deletions(-)
diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
index d25a469..90f1f07 100644
--- a/tools/hv/hv_kvp_daemon.c
+++ b/tools/hv/hv_kvp_daemon.c
@@ -44,6 +44,7 @@
#include
#include
#include
+#include
/*
* KVP protocol: The user mode component first registers with the
@@ -592,26 +593,22 @@ static char *kvp_get_if_name(char *guid)
DIR *dir;
struct dirent *entry;
FILE*file;
- char*p, *q, *x;
+ char*p, *x;
char*if_name = NULL;
charbuf[256];
char *kvp_net_dir = "/sys/class/net/";
- char dev_id[256];
+ char dev_id[PATH_MAX];
dir = opendir(kvp_net_dir);
if (dir == NULL)
return NULL;
- snprintf(dev_id, sizeof(dev_id), "%s", kvp_net_dir);
- q = dev_id + strlen(kvp_net_dir);
-
while ((entry = readdir(dir)) != NULL) {
/*
* Set the state for the next pass.
*/
- *q = '\0';
- strcat(dev_id, entry->d_name);
- strcat(dev_id, "/device/device_id");
+ snprintf(dev_id, sizeof(dev_id), "%s%s/device/device_id",
kvp_net_dir,
+ entry->d_name);
file = fopen(dev_id, "r");
if (file == NULL)
@@ -684,28 +681,23 @@ static char *kvp_mac_to_if_name(char *mac)
DIR *dir;
struct dirent *entry;
FILE*file;
- char*p, *q, *x;
+ char*p, *x;
char*if_name = NULL;
charbuf[256];
char *kvp_net_dir = "/sys/class/net/";
- char dev_id[256];
+ char dev_id[PATH_MAX];
int i;
dir = opendir(kvp_net_dir);
if (dir == NULL)
return NULL;
- snprintf(dev_id, sizeof(dev_id), kvp_net_dir);
- q = dev_id + strlen(kvp_net_dir);
-
while ((entry = readdir(dir)) != NULL) {
/*
* Set the state for the next pass.
*/
- *q = '\0';
-
- strcat(dev_id, entry->d_name);
- strcat(dev_id, "/address");
+ snprintf(dev_id, sizeof(dev_id), "%s%s/address", kvp_net_dir,
+entry->d_name);
file = fopen(dev_id, "r");
if (file == NULL)
--
1.7.11.7
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[PATCH 1/3] tools/hv: Fix for long file names from readdir
kvp_get_if_name and kvp_mac_to_if_name copy strings into statically
sized buffers which could be too small to store really long names.
Buffer sizes have been changed to PATH_MAX, include limits.h where
PATH_MAX is defined was added and length checks ware added via snprintf.
Signed-off-by: Tomas Hozza tho...@redhat.com
---
tools/hv/hv_kvp_daemon.c | 26 +-
1 file changed, 9 insertions(+), 17 deletions(-)
diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
index d25a469..90f1f07 100644
--- a/tools/hv/hv_kvp_daemon.c
+++ b/tools/hv/hv_kvp_daemon.c
@@ -44,6 +44,7 @@
#include fcntl.h
#include dirent.h
#include net/if.h
+#include limits.h
/*
* KVP protocol: The user mode component first registers with the
@@ -592,26 +593,22 @@ static char *kvp_get_if_name(char *guid)
DIR *dir;
struct dirent *entry;
FILE*file;
- char*p, *q, *x;
+ char*p, *x;
char*if_name = NULL;
charbuf[256];
char *kvp_net_dir = /sys/class/net/;
- char dev_id[256];
+ char dev_id[PATH_MAX];
dir = opendir(kvp_net_dir);
if (dir == NULL)
return NULL;
- snprintf(dev_id, sizeof(dev_id), %s, kvp_net_dir);
- q = dev_id + strlen(kvp_net_dir);
-
while ((entry = readdir(dir)) != NULL) {
/*
* Set the state for the next pass.
*/
- *q = '\0';
- strcat(dev_id, entry-d_name);
- strcat(dev_id, /device/device_id);
+ snprintf(dev_id, sizeof(dev_id), %s%s/device/device_id,
kvp_net_dir,
+ entry-d_name);
file = fopen(dev_id, r);
if (file == NULL)
@@ -684,28 +681,23 @@ static char *kvp_mac_to_if_name(char *mac)
DIR *dir;
struct dirent *entry;
FILE*file;
- char*p, *q, *x;
+ char*p, *x;
char*if_name = NULL;
charbuf[256];
char *kvp_net_dir = /sys/class/net/;
- char dev_id[256];
+ char dev_id[PATH_MAX];
int i;
dir = opendir(kvp_net_dir);
if (dir == NULL)
return NULL;
- snprintf(dev_id, sizeof(dev_id), kvp_net_dir);
- q = dev_id + strlen(kvp_net_dir);
-
while ((entry = readdir(dir)) != NULL) {
/*
* Set the state for the next pass.
*/
- *q = '\0';
-
- strcat(dev_id, entry-d_name);
- strcat(dev_id, /address);
+ snprintf(dev_id, sizeof(dev_id), %s%s/address, kvp_net_dir,
+entry-d_name);
file = fopen(dev_id, r);
if (file == NULL)
--
1.7.11.7
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
