From: Arnd Bergmann arnd@arndb.de

It sounds unwise to let user space pass an unchecked 32-bit offset into a kernel structure in an ioctl. This is an unsigned variable, so checking the upper bound for the size of the structure it points into is sufficient to avoid data corruption, but as the pointer might also be unaligned, it has to be written carefully as well.

While I stumbled over this problem by reading the code, I did not continue checking the function for further problems like it.

Cc: stable@vger.kernel.org # v2.6.15+ Fixes: c4a3e0a529ab ("[SCSI] MegaRAID SAS RAID: new driver") Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Arnd Bergmann arnd@arndb.de --- drivers/scsi/megaraid/megaraid_sas_base.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c index 41cd66fc7d81..b1b9a8823c8c 100644 --- a/drivers/scsi/megaraid/megaraid_sas_base.c +++ b/drivers/scsi/megaraid/megaraid_sas_base.c @@ -8134,7 +8134,7 @@ megasas_mgmt_fw_ioctl(struct megasas_instance *instance, int error = 0, i; void *sense = NULL; dma_addr_t sense_handle; - unsigned long *sense_ptr; + void *sense_ptr; u32 opcode = 0; int ret = DCMD_SUCCESS;

@@ -8257,6 +8257,12 @@ megasas_mgmt_fw_ioctl(struct megasas_instance *instance, }

if (ioc->sense_len) { + /* make sure the pointer is part of the frame */ + if (ioc->sense_off > (sizeof(union megasas_frame) - sizeof(__le64))) { + error = -EINVAL; + goto out; + } + sense = dma_alloc_coherent(&instance->pdev->dev, ioc->sense_len, &sense_handle, GFP_KERNEL); if (!sense) { @@ -8264,12 +8270,11 @@ megasas_mgmt_fw_ioctl(struct megasas_instance *instance, goto out; }

- sense_ptr = - (unsigned long *) ((unsigned long)cmd->frame + ioc->sense_off); + sense_ptr = (void *)cmd->frame + ioc->sense_off; if (instance->consistent_mask_64bit) - *sense_ptr = cpu_to_le64(sense_handle); + put_unaligned_le64(sense_handle, sense_ptr); else - *sense_ptr = cpu_to_le32(sense_handle); + put_unaligned_le32(sense_handle, sense_ptr); }

/*