[PATCH] drivers: staging: lustre: replace variable length array by dynamic allocation

[PATCH] drivers: staging: lustre: replace variable length array by dynamic allocation

[Raphaël Beamonte]

Fixes the following sparse warnings:

drivers/staging/lustre/lustre/llite/xattr.c:89:62: warning: Variable
length array is used.
drivers/staging/lustre/lustre/llite/xattr.c:366:62: warning: Variable
length array is used.

Signed-off-by: Raphaël Beamonte <raphael.beamonte@gmail.com>
---
 drivers/staging/lustre/lustre/llite/xattr.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/lustre/lustre/llite/xattr.c b/drivers/staging/lustre/lustre/llite/xattr.c
index 6187bffec8c4..ccfc728d8ec0 100644
--- a/drivers/staging/lustre/lustre/llite/xattr.c
+++ b/drivers/staging/lustre/lustre/llite/xattr.c
@@ -86,7 +86,7 @@ ll_xattr_set_common(const struct xattr_handler *handler,
 		    const char *name, const void *value, size_t size,
 		    int flags)
 {
-	char fullname[strlen(handler->prefix) + strlen(name) + 1];
+	char *fullname;
 	struct ll_sb_info *sbi = ll_i2sbi(inode);
 	struct ptlrpc_request *req = NULL;
 	const char *pv = value;
@@ -140,10 +140,18 @@ ll_xattr_set_common(const struct xattr_handler *handler,
 			return -EPERM;
 	}
 
+	fullname = kmalloc(strlen(handler->prefix) + strlen(name) + 1,
+			   GFP_KERNEL);
+	if (!fullname)
+		return -ENOMEM;
+
 	sprintf(fullname, "%s%s\n", handler->prefix, name);
 	rc = md_setxattr(sbi->ll_md_exp, ll_inode2fid(inode),
 			 valid, fullname, pv, size, 0, flags,
 			 ll_i2suppgid(inode), &req);
+
+	kfree(fullname);
+
 	if (rc) {
 		if (rc == -EOPNOTSUPP && handler->flags == XATTR_USER_T) {
 			LCONSOLE_INFO("Disabling user_xattr feature because it is not supported on the server\n");
@@ -363,7 +371,7 @@ static int ll_xattr_get_common(const struct xattr_handler *handler,
 			       struct dentry *dentry, struct inode *inode,
 			       const char *name, void *buffer, size_t size)
 {
-	char fullname[strlen(handler->prefix) + strlen(name) + 1];
+	char *fullname;
 	struct ll_sb_info *sbi = ll_i2sbi(inode);
 #ifdef CONFIG_FS_POSIX_ACL
 	struct ll_inode_info *lli = ll_i2info(inode);
@@ -410,9 +418,17 @@ static int ll_xattr_get_common(const struct xattr_handler *handler,
 	if (handler->flags == XATTR_ACL_DEFAULT_T && !S_ISDIR(inode->i_mode))
 		return -ENODATA;
 #endif
+	fullname = kmalloc(strlen(handler->prefix) + strlen(name) + 1,
+			   GFP_KERNEL);
+	if (!fullname)
+		return -ENOMEM;
+
 	sprintf(fullname, "%s%s\n", handler->prefix, name);
-	return ll_xattr_list(inode, fullname, handler->flags, buffer, size,
-			     OBD_MD_FLXATTR);
+	rc = ll_xattr_list(inode, fullname, handler->flags, buffer, size,
+			   OBD_MD_FLXATTR);
+
+	kfree(fullname);
+	return rc;
 }
 
 static ssize_t ll_getxattr_lov(struct inode *inode, void *buf, size_t buf_size)
-- 
2.11.0

Re: [PATCH] drivers: staging: lustre: replace variable length array by dynamic allocation

[Greg Kroah-Hartman]

On Tue, May 23, 2017 at 09:32:13PM +0200, Raphaël Beamonte wrote:
> Fixes the following sparse warnings:
> 
> drivers/staging/lustre/lustre/llite/xattr.c:89:62: warning: Variable
> length array is used.
> drivers/staging/lustre/lustre/llite/xattr.c:366:62: warning: Variable
> length array is used.
> 
> Signed-off-by: Raphaël Beamonte <raphael.beamonte@gmail.com>
> ---
>  drivers/staging/lustre/lustre/llite/xattr.c | 24 ++++++++++++++++++++----
>  1 file changed, 20 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/staging/lustre/lustre/llite/xattr.c b/drivers/staging/lustre/lustre/llite/xattr.c
> index 6187bffec8c4..ccfc728d8ec0 100644
> --- a/drivers/staging/lustre/lustre/llite/xattr.c
> +++ b/drivers/staging/lustre/lustre/llite/xattr.c
> @@ -86,7 +86,7 @@ ll_xattr_set_common(const struct xattr_handler *handler,
>  		    const char *name, const void *value, size_t size,
>  		    int flags)
>  {
> -	char fullname[strlen(handler->prefix) + strlen(name) + 1];
> +	char *fullname;
>  	struct ll_sb_info *sbi = ll_i2sbi(inode);
>  	struct ptlrpc_request *req = NULL;
>  	const char *pv = value;
> @@ -140,10 +140,18 @@ ll_xattr_set_common(const struct xattr_handler *handler,
>  			return -EPERM;
>  	}
>  
> +	fullname = kmalloc(strlen(handler->prefix) + strlen(name) + 1,
> +			   GFP_KERNEL);
> +	if (!fullname)
> +		return -ENOMEM;
> +
>  	sprintf(fullname, "%s%s\n", handler->prefix, name);
>  	rc = md_setxattr(sbi->ll_md_exp, ll_inode2fid(inode),
>  			 valid, fullname, pv, size, 0, flags,
>  			 ll_i2suppgid(inode), &req);
> +
> +	kfree(fullname);

Didn't we reject much this same patch last week?

thanks,

greg k-h

Re: [PATCH] drivers: staging: lustre: replace variable length array by dynamic allocation

[Andy Shevchenko]

On Tue, May 23, 2017 at 10:38 PM, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
> On Tue, May 23, 2017 at 09:32:13PM +0200, Raphaël Beamonte wrote:

>> drivers/staging/lustre/lustre/llite/xattr.c:89:62: warning: Variable
>> length array is used.
>> drivers/staging/lustre/lustre/llite/xattr.c:366:62: warning: Variable
>> length array is used.

>> +     fullname = kmalloc(strlen(handler->prefix) + strlen(name) + 1,
>> +                        GFP_KERNEL);
>> +     if (!fullname)
>> +             return -ENOMEM;
>> +
>>       sprintf(fullname, "%s%s\n", handler->prefix, name);
>>       rc = md_setxattr(sbi->ll_md_exp, ll_inode2fid(inode),
>>                        valid, fullname, pv, size, 0, flags,
>>                        ll_i2suppgid(inode), &req);
>> +
>> +     kfree(fullname);
>
> Didn't we reject much this same patch last week?

...besides the fact that kasprintf(); might be better in cases when
malloc + snprintf is used.

-- 
With Best Regards,
Andy Shevchenko