[PATCH] Missing error checking in cmirrord

[PATCH] Missing error checking in cmirrord

[Jonathan Brassow]

There are missing error checks... it's possible for
sprintf to fail.

 brassow

Index: LVM2/daemons/cmirrord/functions.c
===================================================================
--- LVM2.orig/daemons/cmirrord/functions.c
+++ LVM2/daemons/cmirrord/functions.c
@@ -1371,15 +1371,21 @@ static int clog_get_sync_count(struct dm
 
 static int core_status_info(struct log_c *lc __attribute((unused)), struct dm_ulog_request *rq)
 {
+	int r;
 	char *data = (char *)rq->data;
 
-	rq->data_size = sprintf(data, "1 clustered-core");
+	r = sprintf(data, "1 clustered-core");
+	if (r < 0)
+		return r;
+
+	rq->data_size = r;
 
 	return 0;
 }
 
 static int disk_status_info(struct log_c *lc, struct dm_ulog_request *rq)
 {
+	int r;
 	char *data = (char *)rq->data;
 	struct stat statbuf;
 
@@ -1388,9 +1394,13 @@ static int disk_status_info(struct log_c
 		return -errno;
 	}
 
-	rq->data_size = sprintf(data, "3 clustered-disk %d:%d %c",
-				major(statbuf.st_rdev), minor(statbuf.st_rdev),
-				(lc->log_dev_failed) ? 'D' : 'A');
+	r = sprintf(data, "3 clustered-disk %d:%d %c",
+		    major(statbuf.st_rdev), minor(statbuf.st_rdev),
+		    (lc->log_dev_failed) ? 'D' : 'A');
+	if (r < 0)
+		return r;
+
+	rq->data_size = r;
 
 	return 0;
 }
@@ -1421,18 +1431,24 @@ static int clog_status_info(struct dm_ul
 
 static int core_status_table(struct log_c *lc, struct dm_ulog_request *rq)
 {
+	int r;
 	char *data = (char *)rq->data;
 
-	rq->data_size = sprintf(data, "clustered-core %u %s%s ",
-				lc->region_size,
-				(lc->sync == DEFAULTSYNC) ? "" :
-				(lc->sync == NOSYNC) ? "nosync " : "sync ",
-				(lc->block_on_error) ? "block_on_error" : "");
+	r = sprintf(data, "clustered-core %u %s%s ",
+		    lc->region_size,
+		    (lc->sync == DEFAULTSYNC) ? "" :
+		    (lc->sync == NOSYNC) ? "nosync " : "sync ",
+		    (lc->block_on_error) ? "block_on_error" : "");
+	if (r < 0)
+		return r;
+
+	rq->data_size = r;
 	return 0;
 }
 
 static int disk_status_table(struct log_c *lc, struct dm_ulog_request *rq)
 {
+	int r;
 	char *data = (char *)rq->data;
 	struct stat statbuf;
 
@@ -1441,12 +1457,16 @@ static int disk_status_table(struct log_
 		return -errno;
 	}
 
-	rq->data_size = sprintf(data, "clustered-disk %d:%d %u %s%s ",
-				major(statbuf.st_rdev), minor(statbuf.st_rdev),
-				lc->region_size,
-				(lc->sync == DEFAULTSYNC) ? "" :
-				(lc->sync == NOSYNC) ? "nosync " : "sync ",
-				(lc->block_on_error) ? "block_on_error" : "");
+	r = sprintf(data, "clustered-disk %d:%d %u %s%s ",
+		    major(statbuf.st_rdev), minor(statbuf.st_rdev),
+		    lc->region_size,
+		    (lc->sync == DEFAULTSYNC) ? "" :
+		    (lc->sync == NOSYNC) ? "nosync " : "sync ",
+		    (lc->block_on_error) ? "block_on_error" : "");
+	if (r < 0)
+		return r;
+
+	rq->data_size = r;
 	return 0;
 }
 

[PATCH] Missing error checking in cmirrord

[Alasdair G Kergon]

On Fri, Jun 18, 2010 at 04:10:20PM -0500, Jon Brassow wrote:
> There are missing error checks... it's possible for
> sprintf to fail.
 
And an inline comment to explain how data has an adequate minimum size
perhaps?

Alasdair

[PATCH] Missing error checking in cmirrord

[Milan Broz]

On 06/18/2010 11:10 PM, Jonathan Brassow wrote:
> There are missing error checks... it's possible for
> sprintf to fail.
> 
>  brassow
> 
> Index: LVM2/daemons/cmirrord/functions.c
> ===================================================================
> --- LVM2.orig/daemons/cmirrord/functions.c
> +++ LVM2/daemons/cmirrord/functions.c
> @@ -1371,15 +1371,21 @@ static int clog_get_sync_count(struct dm
>  
>  static int core_status_info(struct log_c *lc __attribute((unused)), struct dm_ulog_request *rq)
>  {
> +	int r;
>  	char *data = (char *)rq->data;
>  
> -	rq->data_size = sprintf(data, "1 clustered-core");

	rq->data_size = 0;

> +	r = sprintf(data, "1 clustered-core");
> +	if (r < 0)
> +		return r;
> +
> +	rq->data_size = r;

	rq->data_size = r + 1;

sprintf does not count trailing \0 ... (and this is probably part of
the mysterious fails of cmirrord).

 
Milan