cifs: fix NULL dereference in match_prepath
diff mbox series

Message ID 20200122010756.30245-1-lsahlber@redhat.com
State New
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Series
  • cifs: fix NULL dereference in match_prepath
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Commit Message

Ronnie Sahlberg Jan. 22, 2020, 1:07 a.m. UTC
RHBZ: 1760879

Fix an oops in match_prepath() by making sure that the prepath string is not
NULL before we pass it into strcmp().

This is similar to other checks we make for example in cifs_root_iget()

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
---
 fs/cifs/connect.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Comments

Steve French Jan. 22, 2020, 1:29 a.m. UTC | #1
merged into cifs-2.6.git for-next

On Tue, Jan 21, 2020 at 7:08 PM Ronnie Sahlberg <lsahlber@redhat.com> wrote:
>
> RHBZ: 1760879
>
> Fix an oops in match_prepath() by making sure that the prepath string is not
> NULL before we pass it into strcmp().
>
> This is similar to other checks we make for example in cifs_root_iget()
>
> Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
> ---
>  fs/cifs/connect.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 05ea0e2b7e0e..0aa3623ae0e1 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -3709,8 +3709,10 @@ match_prepath(struct super_block *sb, struct cifs_mnt_data *mnt_data)
>  {
>         struct cifs_sb_info *old = CIFS_SB(sb);
>         struct cifs_sb_info *new = mnt_data->cifs_sb;
> -       bool old_set = old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH;
> -       bool new_set = new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH;
> +       bool old_set = (old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
> +               old->prepath;
> +       bool new_set = (new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
> +               new->prepath;
>
>         if (old_set && new_set && !strcmp(new->prepath, old->prepath))
>                 return 1;
> --
> 2.13.6
>

Patch
diff mbox series

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 05ea0e2b7e0e..0aa3623ae0e1 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3709,8 +3709,10 @@  match_prepath(struct super_block *sb, struct cifs_mnt_data *mnt_data)
 {
 	struct cifs_sb_info *old = CIFS_SB(sb);
 	struct cifs_sb_info *new = mnt_data->cifs_sb;
-	bool old_set = old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH;
-	bool new_set = new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH;
+	bool old_set = (old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
+		old->prepath;
+	bool new_set = (new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
+		new->prepath;
 
 	if (old_set && new_set && !strcmp(new->prepath, old->prepath))
 		return 1;