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authorColin Ian King <colin.king@canonical.com>2018-11-01 13:14:30 +0000
committerSteve French <stfrench@microsoft.com>2018-11-02 14:09:42 -0500
commit8c6c9bed8773375b1d54ccca2911ec892c59db5d (patch)
treec45857d15024dc656dc7a20fb0e75ec46b2f85b8 /fs
parentbe4eb68846dc4450a9a4998d7c16d9f4955f9988 (diff)
downloadlinux-8c6c9bed8773375b1d54ccca2911ec892c59db5d.tar.bz2
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>
Diffstat (limited to 'fs')
-rw-r--r--fs/cifs/cifsfs.c7
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