diff options
| author | David Jeffery <djeffery@redhat.com> | 2009-09-28 13:54:24 -0400 |
|---|---|---|
| committer | James Bottomley <James.Bottomley@suse.de> | 2009-10-02 14:11:58 -0500 |
| commit | 2c2ed8bfd899b84ecbf71d28fcc2cc4ace36c8d9 (patch) | |
| tree | 890fd3916878e2427141d6e53dd70150ac7ff93e | |
| parent | 2afc95bf546a961d2936d886c3802e159f1bae6b (diff) | |
[SCSI] st: fix possible memory use after free after MTSETBLK ioctl
A memory use after free bug can manifest if the MTSETBLK or SET_DENS_AND_BLK
ioctl features are used to set the tape's blocksize from 0 to non-zero.
After the driver sets the new block size, in this one case it calls
normalize_buffer() to free the device's internal data buffers. However, the
ioctl code assumes there is always a buffer and does not check or allocate
a buffer if there isn't one. So any following ioctl calls can corrupt
a part of memory by writing data to memory that the st driver had freed.
This patch removes the normalize_buffer() call and the specialness of
changing from a 0 to non-zero blocksize to fix the possible use of
memory after it has been freed by the st driver.
signed-off-by: David Jeffery <djeffery@redhat.com>
Acked-by: Kai Makisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
| -rw-r--r-- | drivers/scsi/st.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c index b33d04250bb..12d58a7ed6b 100644 --- a/drivers/scsi/st.c +++ b/drivers/scsi/st.c @@ -2859,11 +2859,8 @@ static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned lon ioctl_result = st_int_ioctl(STp, MTBSF, 1); if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) { - int old_block_size = STp->block_size; STp->block_size = arg & MT_ST_BLKSIZE_MASK; if (STp->block_size != 0) { - if (old_block_size == 0) - normalize_buffer(STp->buffer); (STp->buffer)->buffer_blocks = (STp->buffer)->buffer_size / STp->block_size; } |