CVE-2012-3400 (published 2012-10-03T11:02Z)

Heap-based buffer overflow in the udf_load_logicalvol function in fs/udf/super.c in the Linux kernel before 3.4.5 allows remote attackers to cause a denial of service (system crash) or possibly have unspecified other impact via a crafted UDF filesystem.

Severity: HIGH
CVSS v2 base score: 7.6 (AV:N/AC:H/Au:N/C:C/I:C/A:C)

Weakness information:
cwe_id: CWE-787
cwe_name: Out-of-bounds Write
description: The product writes data past the end, or before the beginning, of the intended buffer.
extended_description: 
            
            
             
			 
         
         

Fix information:
repo_url: https://github.com/torvalds/linux
commit_details: repo_url: https://github.com/torvalds/linux
author: Jan Kara
author_date: 2012-06-27 21:23:07+02:00
msg: udf: Fortify loading of sparing table

Add sanity checks when loading sparing table from disk to avoid accessing
unallocated memory or writing to it.

Signed-off-by: Jan Kara <jack@suse.cz>
repository: repo_url: https://github.com/torvalds/linux
repo_name: torvalds/linux
description: Linux kernel source tree
repo_language: C
owner: torvalds
file_changes: filename: super.c
change_type: ModificationType.MODIFY
diff: @@ -56,6 +56,7 @@
 #include <linux/seq_file.h>
 #include <linux/bitmap.h>
 #include <linux/crc-itu-t.h>
+#include <linux/log2.h>
 #include <asm/byteorder.h>
 
 #include "udf_sb.h"
@@ -1215,11 +1216,59 @@ static int udf_load_partdesc(struct super_block *sb, sector_t block)
 	return ret;
 }
 
+static int udf_load_sparable_map(struct super_block *sb,
+				 struct udf_part_map *map,
+				 struct sparablePartitionMap *spm)
+{
+	uint32_t loc;
+	uint16_t ident;
+	struct sparingTable *st;
+	struct udf_sparing_data *sdata = &map->s_type_specific.s_sparing;
+	int i;
+	struct buffer_head *bh;
+
+	map->s_partition_type = UDF_SPARABLE_MAP15;
+	sdata->s_packet_len = le16_to_cpu(spm->packetLength);
+	if (!is_power_of_2(sdata->s_packet_len)) {
+		udf_err(sb, "error loading logical volume descriptor: "
+			"Invalid packet length %u\n",
+			(unsigned)sdata->s_packet_len);
+		return -EIO;
+	}
+	if (spm->numSparingTables > 4) {
+		udf_err(sb, "error loading logical volume descriptor: "
+			"Too many sparing tables (%d)\n",
+			(int)spm->numSparingTables);
+		return -EIO;
+	}
+
+	for (i = 0; i < spm->numSparingTables; i++) {
+		loc = le32_to_cpu(spm->locSparingTable[i]);
+		bh = udf_read_tagged(sb, loc, loc, &ident);
+		if (!bh)
+			continue;
+
+		st = (struct sparingTable *)bh->b_data;
+		if (ident != 0 ||
+		    strncmp(st->sparingIdent.ident, UDF_ID_SPARING,
+			    strlen(UDF_ID_SPARING)) ||
+		    sizeof(*st) + le16_to_cpu(st->reallocationTableLen) >
+							sb->s_blocksize) {
+			brelse(bh);
+			continue;
+		}
+
+		sdata->s_spar_map[i] = bh;
+	}
+	map->s_partition_func = udf_get_pblock_spar15;
+	return 0;
+}
+
 static int udf_load_logicalvol(struct super_block *sb, sector_t block,
 			       struct kernel_lb_addr *fileset)
 {
 	struct logicalVolDesc *lvd;
-	int i, j, offset;
+	int i, offset;
 	uint8_t type;
 	struct udf_sb_info *sbi = UDF_SB(sb);
 	struct genericPartitionMap *gpm;
@@ -1281,38 +1330,9 @@ static int udf_load_logicalvol(struct super_block *sb, sector_t block,
 			} else if (!strncmp(upm2->partIdent.ident,
 						UDF_ID_SPARABLE,
 						strlen(UDF_ID_SPARABLE))) {
-				uint32_t loc;
-				struct sparingTable *st;
-				struct sparablePartitionMap *spm =
-					(struct sparablePartitionMap *)gpm;
-
-				map->s_partition_type = UDF_SPARABLE_MAP15;
-				map->s_type_specific.s_sparing.s_packet_len =
-						le16_to_cpu(spm->packetLength);
-				for (j = 0; j < spm->numSparingTables; j++) {
-					struct buffer_head *bh2;
-
-					loc = le32_to_cpu(
-						spm->locSparingTable[j]);
-					bh2 = udf_read_tagged(sb, loc, loc,
-							     &ident);
-					map->s_type_specific.s_sparing.
-							s_spar_map[j] = bh2;
-
-					if (bh2 == NULL)
-						continue;
-
-					st = (struct sparingTable *)bh2->b_data;
-					if (ident != 0 || strncmp(
-						st->sparingIdent.ident,
-						UDF_ID_SPARING,
-						strlen(UDF_ID_SPARING))) {
-						brelse(bh2);
-						map->s_type_specific.s_sparing.
-							s_spar_map[j] = NULL;
-					}
-				}
-				map->s_partition_func = udf_get_pblock_spar15;
+				if (udf_load_sparable_map(sb, map,
+				    (struct sparablePartitionMap *)gpm) < 0)
+					goto out_bh;
 			} else if (!strncmp(upm2->partIdent.ident,
 						UDF_ID_METADATA,
 						strlen(UDF_ID_METADATA))) {

programming_language: C
repo_url: https://github.com/torvalds/linux
commit_details: repo_url: https://github.com/torvalds/linux
author: Jan Kara
author_date: 2012-06-27 20:20:22+02:00
msg: udf: Avoid run away loop when partition table length is corrupted

Check provided length of partition table so that (possibly maliciously)
corrupted partition table cannot cause accessing data beyond current buffer.

Signed-off-by: Jan Kara <jack@suse.cz>
repository: repo_url: https://github.com/torvalds/linux
repo_name: torvalds/linux
description: Linux kernel source tree
repo_language: C
owner: torvalds
file_changes: filename: super.c
change_type: ModificationType.MODIFY
diff: @@ -1225,6 +1225,7 @@ static int udf_load_logicalvol(struct super_block *sb, sector_t block,
 	struct genericPartitionMap *gpm;
 	uint16_t ident;
 	struct buffer_head *bh;
+	unsigned int table_len;
 	int ret = 0;
 
 	bh = udf_read_tagged(sb, block, block, &ident);
@@ -1232,13 +1233,20 @@ static int udf_load_logicalvol(struct super_block *sb, sector_t block,
 		return 1;
 	BUG_ON(ident != TAG_IDENT_LVD);
 	lvd = (struct logicalVolDesc *)bh->b_data;
+	table_len = le32_to_cpu(lvd->mapTableLength);
+	if (sizeof(*lvd) + table_len > sb->s_blocksize) {
+		udf_err(sb, "error loading logical volume descriptor: "
+			"Partition table too long (%u > %lu)\n", table_len,
+			sb->s_blocksize - sizeof(*lvd));
+		goto out_bh;
+	}
 
 	ret = udf_sb_alloc_partition_maps(sb, le32_to_cpu(lvd->numPartitionMaps));
 	if (ret)
 		goto out_bh;
 
 	for (i = 0, offset = 0;
-	     i < sbi->s_partitions && offset < le32_to_cpu(lvd->mapTableLength);
+	     i < sbi->s_partitions && offset < table_len;
 	     i++, offset += gpm->partitionMapLength) {
 		struct udf_part_map *map = &sbi->s_partmaps[i];
 		gpm = (struct genericPartitionMap *)

programming_language: C