diff options
| author | Colin Ian King <colin.king@canonical.com> | 2018-11-01 13:14:30 +0000 |
|---|---|---|
| committer | Steve French <stfrench@microsoft.com> | 2018-11-02 14:09:42 -0500 |
| commit | 8c6c9bed8773375b1d54ccca2911ec892c59db5d (patch) | |
| tree | c45857d15024dc656dc7a20fb0e75ec46b2f85b8 | |
| parent | be4eb68846dc4450a9a4998d7c16d9f4955f9988 (diff) | |
| download | linux-8c6c9bed8773375b1d54ccca2911ec892c59db5d.tar.gz | |
cifs: don't dereference smb_file_target before null check
There is a null check on dst_file->private data which suggests
it can be potentially null. However, before this check, pointer
smb_file_target is derived from dst_file->private and dereferenced
in the call to tlink_tcon, hence there is a potential null pointer
deference.
Fix this by assigning smb_file_target and target_tcon after the
null pointer sanity checks.
Detected by CoverityScan, CID#1475302 ("Dereference before null check")
Fixes: 04b38d601239 ("vfs: pull btrfs clone API to vfs layer")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
| -rw-r--r-- | fs/cifs/cifsfs.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index 1b21262ec874..865706edb307 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -999,8 +999,8 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, struct inode *src_inode = file_inode(src_file); struct inode *target_inode = file_inode(dst_file); struct cifsFileInfo *smb_file_src = src_file->private_data; - struct cifsFileInfo *smb_file_target = dst_file->private_data; - struct cifs_tcon *target_tcon = tlink_tcon(smb_file_target->tlink); + struct cifsFileInfo *smb_file_target; + struct cifs_tcon *target_tcon; unsigned int xid; int rc; @@ -1017,6 +1017,9 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, goto out; } + smb_file_target = dst_file->private_data; + target_tcon = tlink_tcon(smb_file_target->tlink); + /* * Note: cifs case is easier than btrfs since server responsible for * checks for proper open modes and file type and if it wants |