From: Arnd Bergmann <arnd@xxxxxxxx> commit 381d34e376e3d9d27730fda8a0e870600e6c8196 upstream. 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. Link: https://lore.kernel.org/r/20201030164450.1253641-2-arnd@xxxxxxxxxx Fixes: c4a3e0a529ab ("[SCSI] MegaRAID SAS RAID: new driver") Cc: <stable@xxxxxxxxxxxxxxx> # v2.6.15+ Reviewed-by: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/scsi/megaraid/megaraid_sas_base.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) --- a/drivers/scsi/megaraid/megaraid_sas_base.c +++ b/drivers/scsi/megaraid/megaraid_sas_base.c @@ -8095,7 +8095,7 @@ megasas_mgmt_fw_ioctl(struct megasas_ins 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; @@ -8218,6 +8218,13 @@ megasas_mgmt_fw_ioctl(struct megasas_ins } 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) { @@ -8225,12 +8232,11 @@ megasas_mgmt_fw_ioctl(struct megasas_ins 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); } /*
