Hello,
Thank you for the report!
On 06/07/2025 11:22, Purva Yeshi wrote:
> Fix Smatch-detected error:
> drivers/block/floppy.c:3569 fd_locked_ioctl() error:
> uninitialized symbol 'outparam'.
>
This a false-positive diagnostic. Smatch doesn't see the dependency
between FDGET... commands and _IOC_READ.
> Use the outparam pointer only after it is explicitly initialized.
> Previously, fd_copyout() was called unconditionally after the switch-case
> statement, assuming outparam would always be set when _IOC_READ was active.
if (_IOC_DIR(cmd) & _IOC_READ)
return fd_copyout((void __user *)param, outparam, size);
and all FDGET... macro are defined as _IOR(...).
> However, not all paths ensured this, which led to potential use of an
> uninitialized pointer.
Not all paths, but commands that fall under _IOC_READ condition.
>
> Move fd_copyout() calls directly into the relevant case blocks immediately
> after outparam is set. This ensures it is only called when safe and
> applicable.
If you want to suppress this "error" you can just initialize outparam
to NULL.
>
> Signed-off-by: Purva Yeshi <purvayeshi550@xxxxxxxxx>
> ---
> drivers/block/floppy.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
> index e97432032f01..34ef756bb3b7 100644
> --- a/drivers/block/floppy.c
> +++ b/drivers/block/floppy.c
> @@ -3482,6 +3482,7 @@ static int fd_locked_ioctl(struct block_device *bdev, blk_mode_t mode,
> memcpy(&inparam.g, outparam,
> offsetof(struct floppy_struct, name));
> outparam = &inparam.g;
> + return fd_copyout((void __user *)param, outparam, size);
> break;
> case FDMSGON:
> drive_params[drive].flags |= FTD_MSG;
> @@ -3515,6 +3516,7 @@ static int fd_locked_ioctl(struct block_device *bdev, blk_mode_t mode,
> return 0;
> case FDGETMAXERRS:
> outparam = &drive_params[drive].max_errors;
> + return fd_copyout((void __user *)param, outparam, size);
> break;
> case FDSETMAXERRS:
> drive_params[drive].max_errors = inparam.max_errors;
> @@ -3522,6 +3524,7 @@ static int fd_locked_ioctl(struct block_device *bdev, blk_mode_t mode,
> case FDGETDRVTYP:
> outparam = drive_name(type, drive);
> SUPBOUND(size, strlen((const char *)outparam) + 1);
> + return fd_copyout((void __user *)param, outparam, size);
> break;
> case FDSETDRVPRM:
> if (!valid_floppy_drive_params(inparam.dp.autodetect,
> @@ -3531,6 +3534,7 @@ static int fd_locked_ioctl(struct block_device *bdev, blk_mode_t mode,
> break;
> case FDGETDRVPRM:
> outparam = &drive_params[drive];
> + return fd_copyout((void __user *)param, outparam, size);
> break;
> case FDPOLLDRVSTAT:
> if (lock_fdc(drive))
> @@ -3541,17 +3545,20 @@ static int fd_locked_ioctl(struct block_device *bdev, blk_mode_t mode,
> fallthrough;
> case FDGETDRVSTAT:
> outparam = &drive_state[drive];
> + return fd_copyout((void __user *)param, outparam, size);
> break;
> case FDRESET:
> return user_reset_fdc(drive, (int)param, true);
> case FDGETFDCSTAT:
> outparam = &fdc_state[FDC(drive)];
> + return fd_copyout((void __user *)param, outparam, size);
> break;
> case FDWERRORCLR:
> memset(&write_errors[drive], 0, sizeof(write_errors[drive]));
> return 0;
> case FDWERRORGET:
> outparam = &write_errors[drive];
> + return fd_copyout((void __user *)param, outparam, size);
> break;
> case FDRAWCMD:
> return floppy_raw_cmd_ioctl(type, drive, cmd, (void __user *)param);
> @@ -3565,9 +3572,6 @@ static int fd_locked_ioctl(struct block_device *bdev, blk_mode_t mode,
> return -EINVAL;
> }
>
> - if (_IOC_DIR(cmd) & _IOC_READ)
> - return fd_copyout((void __user *)param, outparam, size);
> -
> return 0;
> }
>
Thanks,
Denis
