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authorLinus Torvalds <torvalds@linux-foundation.org>2016-05-17 14:25:02 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-17 14:25:02 -0700
commit820c687b70ae2c72972240b83c053cb7c85ddbc3 (patch)
tree8a144e528f287c3e05ba97a60ade45be91f6255c
parentdba1e987312ed318dfd46d4684e9e97b2223f2e8 (diff)
parent2a28900be20640fcd1e548b1e3bad79e8221fcf9 (diff)
downloadlinux-820c687b70ae2c72972240b83c053cb7c85ddbc3.tar.bz2
Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull UDF fixes from Jan Kara: "A fix for UDF crash on corrupted media and one UDF header fixup" * 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: udf: Export superblock magic to userspace udf: Prevent stack overflow on corrupted filesystem mount
-rw-r--r--fs/udf/super.c67
-rw-r--r--fs/udf/udf_sb.h4
-rw-r--r--include/uapi/linux/magic.h2
3 files changed, 46 insertions, 27 deletions
diff --git a/fs/udf/super.c b/fs/udf/super.c
index 36661acaf33b..5e2c8c814e1b 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -78,6 +78,15 @@
#define VSD_FIRST_SECTOR_OFFSET 32768
#define VSD_MAX_SECTOR_OFFSET 0x800000
+/*
+ * Maximum number of Terminating Descriptor / Logical Volume Integrity
+ * Descriptor redirections. The chosen numbers are arbitrary - just that we
+ * hopefully don't limit any real use of rewritten inode on write-once media
+ * but avoid looping for too long on corrupted media.
+ */
+#define UDF_MAX_TD_NESTING 64
+#define UDF_MAX_LVID_NESTING 1000
+
enum { UDF_MAX_LINKS = 0xffff };
/* These are the "meat" - everything else is stuffing */
@@ -1541,42 +1550,52 @@ out_bh:
}
/*
- * udf_load_logicalvolint
- *
+ * Find the prevailing Logical Volume Integrity Descriptor.
*/
static void udf_load_logicalvolint(struct super_block *sb, struct kernel_extent_ad loc)
{
- struct buffer_head *bh = NULL;
+ struct buffer_head *bh, *final_bh;
uint16_t ident;
struct udf_sb_info *sbi = UDF_SB(sb);
struct logicalVolIntegrityDesc *lvid;
+ int indirections = 0;
+
+ while (++indirections <= UDF_MAX_LVID_NESTING) {
+ final_bh = NULL;
+ while (loc.extLength > 0 &&
+ (bh = udf_read_tagged(sb, loc.extLocation,
+ loc.extLocation, &ident))) {
+ if (ident != TAG_IDENT_LVID) {
+ brelse(bh);
+ break;
+ }
+
+ brelse(final_bh);
+ final_bh = bh;
- while (loc.extLength > 0 &&
- (bh = udf_read_tagged(sb, loc.extLocation,
- loc.extLocation, &ident)) &&
- ident == TAG_IDENT_LVID) {
- sbi->s_lvid_bh = bh;
- lvid = (struct logicalVolIntegrityDesc *)bh->b_data;
+ loc.extLength -= sb->s_blocksize;
+ loc.extLocation++;
+ }
- if (lvid->nextIntegrityExt.extLength)
- udf_load_logicalvolint(sb,
- leea_to_cpu(lvid->nextIntegrityExt));
+ if (!final_bh)
+ return;
- if (sbi->s_lvid_bh != bh)
- brelse(bh);
- loc.extLength -= sb->s_blocksize;
- loc.extLocation++;
+ brelse(sbi->s_lvid_bh);
+ sbi->s_lvid_bh = final_bh;
+
+ lvid = (struct logicalVolIntegrityDesc *)final_bh->b_data;
+ if (lvid->nextIntegrityExt.extLength == 0)
+ return;
+
+ loc = leea_to_cpu(lvid->nextIntegrityExt);
}
- if (sbi->s_lvid_bh != bh)
- brelse(bh);
+
+ udf_warn(sb, "Too many LVID indirections (max %u), ignoring.\n",
+ UDF_MAX_LVID_NESTING);
+ brelse(sbi->s_lvid_bh);
+ sbi->s_lvid_bh = NULL;
}
-/*
- * Maximum number of Terminating Descriptor redirections. The chosen number is
- * arbitrary - just that we hopefully don't limit any real use of rewritten
- * inode on write-once media but avoid looping for too long on corrupted media.
- */
-#define UDF_MAX_TD_NESTING 64
/*
* Process a main/reserve volume descriptor sequence.
diff --git a/fs/udf/udf_sb.h b/fs/udf/udf_sb.h
index 1f32c7bd9f57..27b5335730c9 100644
--- a/fs/udf/udf_sb.h
+++ b/fs/udf/udf_sb.h
@@ -3,9 +3,7 @@
#include <linux/mutex.h>
#include <linux/bitops.h>
-
-/* Since UDF 2.01 is ISO 13346 based... */
-#define UDF_SUPER_MAGIC 0x15013346
+#include <linux/magic.h>
#define UDF_MAX_READ_VERSION 0x0250
#define UDF_MAX_WRITE_VERSION 0x0201
diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h
index 0de181ad73d5..546b38886e11 100644
--- a/include/uapi/linux/magic.h
+++ b/include/uapi/linux/magic.h
@@ -78,5 +78,7 @@
#define BTRFS_TEST_MAGIC 0x73727279
#define NSFS_MAGIC 0x6e736673
#define BPF_FS_MAGIC 0xcafe4a11
+/* Since UDF 2.01 is ISO 13346 based... */
+#define UDF_SUPER_MAGIC 0x15013346
#endif /* __LINUX_MAGIC_H__ */