File util-linux-libblkid-partition-loop.patch of Package python-libmount.3352

Overview Repositories Revisions Requests Users Attributes Meta

File util-linux-libblkid-partition-loop.patch of Package python-libmount.3352

From 7164a1c34d18831ac61c6744ad14ce916d389b3f Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Thu, 7 Jul 2016 14:22:41 +0200
Subject: [PATCH] libblkid: ignore extended partition at zero offset

If the extended partition starts at zero LBA then MBR is interpreted
as EBR and all is recursively parsed... result is out-of-memory.

MBR --extended-partition--> EBR --> MBR --> ENB --> MBR ...

Note that such PT is not possible to create by standard partitioning
tools.

Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1349536
Signed-off-by: Karel Zak <kzak@redhat.com>
---
 libblkid/src/partitions/dos.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/libblkid/src/partitions/dos.c b/libblkid/src/partitions/dos.c
index 9bba32f..e79f124 100644
--- a/libblkid/src/partitions/dos.c
+++ b/libblkid/src/partitions/dos.c
@@ -47,6 +47,12 @@ static int parse_dos_extended(blkid_probe pr, blkid_parttable tab,
 	int ct_nodata = 0;	/* count ext.partitions without data partitions */
 	int i;
 
+	DBG(LOWPROBE, ul_debug("parse EBR [start=%d, size=%d]", ex_start/ssf, ex_size/ssf));
+	if (ex_start == 0) {
+		DBG(LOWPROBE, ul_debug("Bad offset in primary extended partition -- ignore"));
+		return 0;
+	}
+
 	while (1) {
 		struct dos_partition *p, *p0;
 		uint32_t start, size;
@@ -116,8 +122,12 @@ static int parse_dos_extended(blkid_probe pr, blkid_parttable tab,
 			start = dos_partition_get_start(p) * ssf;
 			size = dos_partition_get_size(p) * ssf;
 
-			if (size && is_extended(p))
-				break;
+			if (size && is_extended(p)) {
+				if (start == 0)
+					DBG(LOWPROBE, ul_debug("#%d: EBR link offset is zero -- ignore", i + 1));
+				else
+					break;
+			}
 		}
 		if (i == 4)
 			goto leave;
-- 
2.9.0

Places

File util-linux-libblkid-partition-loop.patch of Package python-libmount.3352

Places