[bug report] ext4: optimize case-insensitive lookups

[bug report] ext4: optimize case-insensitive lookups

[Dan Carpenter]

Hello Gabriel Krisman Bertazi,

The patch 3ae72562ad91: "ext4: optimize case-insensitive lookups"
from Jun 19, 2019, leads to the following static checker warning:

	fs/ext4/namei.c:1311 ext4_fname_setup_ci_filename()
	warn: 'cf_name->len' unsigned <= 0

fs/ext4/namei.c
  1296  void ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
  1297                                    struct fscrypt_str *cf_name)
  1298  {
  1299          if (!IS_CASEFOLDED(dir)) {
  1300                  cf_name->name = NULL;
  1301                  return;
  1302          }
  1303  
  1304          cf_name->name = kmalloc(EXT4_NAME_LEN, GFP_NOFS);
  1305          if (!cf_name->name)
  1306                  return;
  1307  
  1308          cf_name->len = utf8_casefold(EXT4_SB(dir->i_sb)->s_encoding,
  1309                                       iname, cf_name->name,
  1310                                       EXT4_NAME_LEN);

utf8_casefold() returns negative error codes

  1311          if (cf_name->len <= 0) {

but "cf_name->len" is a u32.

  1312                  kfree(cf_name->name);
  1313                  cf_name->name = NULL;
  1314          }
  1315  }


regards,
dan carpenter

[PATCH] ext4: Fix coverity warning on error path of filename setup

[Gabriel Krisman Bertazi]

Dan Carpenter <dan.carpenter@oracle.com> writes:

> Hello Gabriel Krisman Bertazi,
>
> The patch 3ae72562ad91: "ext4: optimize case-insensitive lookups"
> from Jun 19, 2019, leads to the following static checker warning:

Hi,

The patch below should fix this issue.

-- >8 --
Subject: [PATCH] ext4: Fix coverity warning on error path of filename setup

Fix the following coverity warning reported by Dan Carpenter:

fs/ext4/namei.c:1311 ext4_fname_setup_ci_filename()
	  warn: 'cf_name->len' unsigned <= 0

Fixes: 3ae72562ad91 ("ext4: optimize case-insensitive lookups")
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 fs/ext4/namei.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 4909ced4e672..898295286676 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1296,6 +1296,8 @@ int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
 void ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
 				  struct fscrypt_str *cf_name)
 {
+	int len;
+
 	if (!IS_CASEFOLDED(dir)) {
 		cf_name->name = NULL;
 		return;
@@ -1305,13 +1307,16 @@ void ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
 	if (!cf_name->name)
 		return;
 
-	cf_name->len = utf8_casefold(EXT4_SB(dir->i_sb)->s_encoding,
-				     iname, cf_name->name,
-				     EXT4_NAME_LEN);
-	if (cf_name->len <= 0) {
+	len = utf8_casefold(EXT4_SB(dir->i_sb)->s_encoding,
+			    iname, cf_name->name,
+			    EXT4_NAME_LEN);
+	if (len <= 0) {
 		kfree(cf_name->name);
 		cf_name->name = NULL;
+		return;
 	}
+	cf_name->len = (unsigned) len;
+
 }
 #endif
 
-- 
2.20.1

Re: [PATCH] ext4: Fix coverity warning on error path of filename setup

[Theodore Ts'o]

On Fri, Jun 28, 2019 at 04:19:32PM -0400, Gabriel Krisman Bertazi wrote:
> Dan Carpenter <dan.carpenter@oracle.com> writes:
> 
> > Hello Gabriel Krisman Bertazi,
> >
> > The patch 3ae72562ad91: "ext4: optimize case-insensitive lookups"
> > from Jun 19, 2019, leads to the following static checker warning:
> 
> Hi,
> 
> The patch below should fix this issue.
> 
> -- >8 --
> Subject: [PATCH] ext4: Fix coverity warning on error path of filename setup
> 
> Fix the following coverity warning reported by Dan Carpenter:
> 
> fs/ext4/namei.c:1311 ext4_fname_setup_ci_filename()
> 	  warn: 'cf_name->len' unsigned <= 0
> 
> Fixes: 3ae72562ad91 ("ext4: optimize case-insensitive lookups")
> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

Applied, thanks.

					- Ted