ksmbd: use vfs_llseek instead of dereferencing NULL

commit 067baa9a37 upstream.

By not checking whether llseek is NULL, this might jump to NULL. Also,
it doesn't check FMODE_LSEEK. Fix this by using vfs_llseek(), which
always does the right thing.

Fixes: f441584858 ("cifsd: add file operations")
Cc: stable@vger.kernel.org
Cc: linux-cifs@vger.kernel.org
Cc: Ronnie Sahlberg <lsahlber@redhat.com>
Cc: Hyunchul Lee <hyc.lee@gmail.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jason A. Donenfeld 2022-06-25 13:01:08 +02:00 committed by Greg Kroah-Hartman
parent 9d48194d3e
commit e33f5b5815

View file

@ -1051,7 +1051,7 @@ int ksmbd_vfs_fqar_lseek(struct ksmbd_file *fp, loff_t start, loff_t length,
*out_count = 0;
end = start + length;
while (start < end && *out_count < in_count) {
extent_start = f->f_op->llseek(f, start, SEEK_DATA);
extent_start = vfs_llseek(f, start, SEEK_DATA);
if (extent_start < 0) {
if (extent_start != -ENXIO)
ret = (int)extent_start;
@ -1061,7 +1061,7 @@ int ksmbd_vfs_fqar_lseek(struct ksmbd_file *fp, loff_t start, loff_t length,
if (extent_start >= end)
break;
extent_end = f->f_op->llseek(f, extent_start, SEEK_HOLE);
extent_end = vfs_llseek(f, extent_start, SEEK_HOLE);
if (extent_end < 0) {
if (extent_end != -ENXIO)
ret = (int)extent_end;