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Date: Wed, 28 Feb 2024 11:12:06 -0500
From: Alan Stern <stern@rowland.harvard.edu>
To: syzbot <syzbot+28748250ab47a8f04100@syzkaller.appspotmail.com>
Cc: bvanassche@acm.org, emilne@redhat.com, gregkh@linuxfoundation.org,
  linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
  martin.petersen@oracle.com, syzkaller-bugs@googlegroups.com,
  tasos@tasossah.com, usb-storage@lists.one-eyed-alien.net
Subject: Re: [syzbot] [usb-storage?] divide error in isd200_ata_command
Message-ID: <13add23d-af18-4f84-9f1a-043932a9712b@rowland.harvard.edu>
References: <8fe3f46c-4ee5-4597-bf2d-12a5d634a264@rowland.harvard.edu>
 <0000000000008b026406126a4bbe@google.com>
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On Tue, Feb 27, 2024 at 09:20:03PM -0800, syzbot wrote:
> Hello,
> 
> syzbot tried to test the proposed patch but the build/boot failed:
> 
> failed to checkout kernel repo https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/ on commit f2e367d6ad3b: failed to run ["git" "fetch" "--force" "--tags" "7b440d1b40dd93ea98b5af6bba55ffca63425216" "f2e367d6ad3b"]: exit status 128
> fatal: couldn't find remote ref f2e367d6ad3b

I'm going to guess this was a temporary failure and try again.  If that 
wasn't the case, something is seriously wrong somewhere.  I had no 
trouble accessing that commit using the git.kernel.org web interface.

Alan Stern

On Mon, Feb 26, 2024 at 01:42:26AM -0800, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    f2e367d6ad3b Merge tag 'for-6.8/dm-fix-3' of git://git.ker..
> git tree:       upstream

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/ f2e367d6ad3b

Index: usb-devel/drivers/usb/storage/isd200.c
===================================================================
--- usb-devel.orig/drivers/usb/storage/isd200.c
+++ usb-devel/drivers/usb/storage/isd200.c
@@ -1105,7 +1105,7 @@ static void isd200_dump_driveid(struct u
 static int isd200_get_inquiry_data( struct us_data *us )
 {
 	struct isd200_info *info = (struct isd200_info *)us->extra;
-	int retStatus = ISD200_GOOD;
+	int retStatus;
 	u16 *id = info->id;
 
 	usb_stor_dbg(us, "Entering isd200_get_inquiry_data\n");
@@ -1137,6 +1137,13 @@ static int isd200_get_inquiry_data( stru
 				isd200_fix_driveid(id);
 				isd200_dump_driveid(us, id);
 
+				/* Prevent division by 0 in isd200_scsi_to_ata() */
+				if (id[ATA_ID_HEADS] == 0 || id[ATA_ID_SECTORS] == 0) {
+					usb_stor_dbg(us, "   Invalid ATA Identify data\n");
+					retStatus = ISD200_ERROR;
+					goto Done;
+				}
+
 				memset(&info->InquiryData, 0, sizeof(info->InquiryData));
 
 				/* Standard IDE interface only supports disks */
@@ -1202,6 +1209,7 @@ static int isd200_get_inquiry_data( stru
 		}
 	}
 
+ Done:
 	usb_stor_dbg(us, "Leaving isd200_get_inquiry_data %08X\n", retStatus);
 
 	return(retStatus);
@@ -1481,22 +1489,27 @@ static int isd200_init_info(struct us_da
 
 static int isd200_Initialization(struct us_data *us)
 {
+	int rc = 0;
+
 	usb_stor_dbg(us, "ISD200 Initialization...\n");
 
 	/* Initialize ISD200 info struct */
 
-	if (isd200_init_info(us) == ISD200_ERROR) {
+	if (isd200_init_info(us) < 0) {
 		usb_stor_dbg(us, "ERROR Initializing ISD200 Info struct\n");
+		rc = -ENOMEM;
 	} else {
 		/* Get device specific data */
 
-		if (isd200_get_inquiry_data(us) != ISD200_GOOD)
+		if (isd200_get_inquiry_data(us) != ISD200_GOOD) {
 			usb_stor_dbg(us, "ISD200 Initialization Failure\n");
-		else
+			rc = -EINVAL;
+		} else {
 			usb_stor_dbg(us, "ISD200 Initialization complete\n");
+		}
 	}
 
-	return 0;
+	return rc;
 }