linux-kernel - [PATCH v2 2/3] scsi: megaraid_sas: check user-provided offsets

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200918121522.1466028-1-arnd@arndb.de>
Date:   Fri, 18 Sep 2020 14:15:22 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Kashyap Desai <kashyap.desai@...adcom.com>,
        Sumit Saxena <sumit.saxena@...adcom.com>,
        Shivasharan S <shivasharan.srikanteshwara@...adcom.com>,
        "James E . J . Bottomley" <jejb@...ux.ibm.com>,
        "Martin K . Petersen" <martin.petersen@...cle.com>
Cc:     Christoph Hellwig <hch@...radead.org>, anand.lodnoor@...adcom.com,
        megaraidlinux.pdl@...adcom.com, linux-scsi@...r.kernel.org,
        linux-kernel@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
        stable@...r.kernel.org, Christoph Hellwig <hch@....de>
Subject: [PATCH v2 2/3] 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.

Cc: <stable@...r.kernel.org> # v2.6.15+
Fixes: c4a3e0a529ab ("[SCSI] MegaRAID SAS RAID: new driver")
Reviewed-by: Christoph Hellwig <hch@....de>
Signed-off-by: Arnd Bergmann <arnd@...db.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 861f7140f52e..c3de69f3bee8 100644
--- 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_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;
 
@@ -8218,6 +8218,12 @@ 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) {
@@ -8225,12 +8231,11 @@ 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);
 	}
 
 	/*
-- 
2.27.0