The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 381d34e376e3d9d27730fda8a0e870600e6c8196 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann <arnd@xxxxxxxx> Date: Fri, 30 Oct 2020 17:44:20 +0100 Subject: [PATCH] scsi: megaraid_sas: Check user-provided offsets 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> diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c index 41cd66fc7d81..5e31bd364a5b 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 +8257,13 @@ 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 +8271,11 @@ 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); } /*
