Commit 984f1733 authored Sep 06, 2013 by Alan Stern Committed by James Bottomley Sep 11, 2013

[SCSI] sd: Fix potential out-of-bounds access



This patch fixes an out-of-bounds error in sd_read_cache_type(), found
by Google's AddressSanitizer tool.  When the loop ends, we know that
"offset" lies beyond the end of the data in the buffer, so no Caching
mode page was found.  In theory it may be present, but the buffer size
is limited to 512 bytes.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
CC: <stable@vger.kernel.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

parent 76c4f79d

drivers/scsi/sd.c

+3 −8

Original line number	Diff line number	Diff line
		@@ -2420,14 +2420,9 @@ sd_read_cache_type(struct scsi_disk sdkp, unsigned char buffer)
		}
		}

		if (modepage == 0x3F) {
		sd_printk(KERN_ERR, sdkp, "No Caching mode page "
		"present\n");
		sd_printk(KERN_ERR, sdkp, "No Caching mode page found\n");
		goto defaults;
		} else if ((buffer[offset] & 0x3f) != modepage) {
		sd_printk(KERN_ERR, sdkp, "Got wrong page\n");
		goto defaults;
		}

		Page_found:
		if (modepage == 8) {
		sdkp->WCE = ((buffer[offset + 2] & 0x04) != 0);

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