Jan -
Tested-by: Steven J. Magnani <steve@xxxxxxxxxxxxxxx>
Reviewed-by: Steven J. Magnani <steve@xxxxxxxxxxxxxxx>
On 8/29/19 7:25 AM, Jan Kara wrote:
OSTA UDF standard defines that domain identifier in logical volume
descriptor and file set descriptor should contain a particular string
and the identifier suffix contains flags possibly making media
write-protected. Verify these constraints and allow only read-only mount
if they are not met.
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/udf/ecma_167.h | 14 +++++++++
fs/udf/super.c | 91 ++++++++++++++++++++++++++++++++++++++-----------------
2 files changed, 78 insertions(+), 27 deletions(-)
diff --git a/fs/udf/ecma_167.h b/fs/udf/ecma_167.h
index 9f24bd1a9f44..fb7f2c7bec9c 100644
--- a/fs/udf/ecma_167.h
+++ b/fs/udf/ecma_167.h
@@ -88,6 +88,20 @@ struct regid {
#define ENTITYID_FLAGS_DIRTY 0x00
#define ENTITYID_FLAGS_PROTECTED 0x01
+/* OSTA UDF 2.1.5.2 */
+#define UDF_ID_COMPLIANT "*OSTA UDF Compliant"
+
+/* OSTA UDF 2.1.5.3 */
+struct domainEntityIDSuffix {
+ uint16_t revision;
+ uint8_t flags;
+ uint8_t reserved[5];
+};
+
+/* OSTA UDF 2.1.5.3 */
+#define ENTITYIDSUFFIX_FLAGS_HARDWRITEPROTECT 0
+#define ENTITYIDSUFFIX_FLAGS_SOFTWRITEPROTECT 1
+
/* Volume Structure Descriptor (ECMA 167r3 2/9.1) */
#define VSD_STD_ID_LEN 5
struct volStructDesc {
diff --git a/fs/udf/super.c b/fs/udf/super.c
index a14346137361..42db3dd51dfc 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -94,8 +94,8 @@ static int udf_remount_fs(struct super_block *, int *, char *);
static void udf_load_logicalvolint(struct super_block *, struct kernel_extent_ad);
static int udf_find_fileset(struct super_block *, struct kernel_lb_addr *,
struct kernel_lb_addr *);
-static void udf_load_fileset(struct super_block *, struct buffer_head *,
- struct kernel_lb_addr *);
+static int udf_load_fileset(struct super_block *, struct fileSetDesc *,
+ struct kernel_lb_addr *);
static void udf_open_lvid(struct super_block *);
static void udf_close_lvid(struct super_block *);
static unsigned int udf_count_free(struct super_block *);
@@ -757,28 +757,27 @@ static int udf_find_fileset(struct super_block *sb,
{
struct buffer_head *bh = NULL;
uint16_t ident;
+ int ret;
- if (fileset->logicalBlockNum != 0xFFFFFFFF ||
- fileset->partitionReferenceNum != 0xFFFF) {
- bh = udf_read_ptagged(sb, fileset, 0, &ident);
-
- if (!bh) {
- return 1;
- } else if (ident != TAG_IDENT_FSD) {
- brelse(bh);
- return 1;
- }
-
- udf_debug("Fileset at block=%u, partition=%u\n",
- fileset->logicalBlockNum,
- fileset->partitionReferenceNum);
+ if (fileset->logicalBlockNum == 0xFFFFFFFF &&
+ fileset->partitionReferenceNum == 0xFFFF)
+ return -EINVAL;
- UDF_SB(sb)->s_partition = fileset->partitionReferenceNum;
- udf_load_fileset(sb, bh, root);
+ bh = udf_read_ptagged(sb, fileset, 0, &ident);
+ if (!bh)
+ return -EIO;
+ if (ident != TAG_IDENT_FSD) {
brelse(bh);
- return 0;
+ return -EINVAL;
}
- return 1;
+
+ udf_debug("Fileset at block=%u, partition=%u\n",
+ fileset->logicalBlockNum, fileset->partitionReferenceNum);
+
+ UDF_SB(sb)->s_partition = fileset->partitionReferenceNum;
+ ret = udf_load_fileset(sb, (struct fileSetDesc *)bh->b_data, root);
+ brelse(bh);
+ return ret;
}
/*
@@ -939,19 +938,53 @@ static int udf_load_metadata_files(struct super_block *sb, int partition,
return 0;
}
-static void udf_load_fileset(struct super_block *sb, struct buffer_head *bh,
- struct kernel_lb_addr *root)
+static int udf_verify_domain_identifier(struct super_block *sb,
+ struct regid *ident, char *dname)
The latter two can be 'const'.
{
- struct fileSetDesc *fset;
+ struct domainEntityIDSuffix *suffix;
- fset = (struct fileSetDesc *)bh->b_data;
+ if (memcmp(ident->ident, UDF_ID_COMPLIANT, strlen(UDF_ID_COMPLIANT))) {
+ udf_warn(sb, "Not OSTA UDF compliant %s descriptor.\n", dname);
+ goto force_ro;
+ }
+ if (ident->flags & (1 << ENTITYID_FLAGS_DIRTY)) {
+ udf_warn(sb, "Possibly not OSTA UDF compliant %s descriptor.\n",
+ dname);
+ goto force_ro;
+ }
+ suffix = (struct domainEntityIDSuffix *)ident->identSuffix;
+ if (suffix->flags & (1 << ENTITYIDSUFFIX_FLAGS_HARDWRITEPROTECT) ||
+ suffix->flags & (1 << ENTITYIDSUFFIX_FLAGS_SOFTWRITEPROTECT)) {
+ if (!sb_rdonly(sb)) {
+ udf_warn(sb, "Descriptor for %s marked write protected."
+ " Forcing read only mount.\n", dname);
+ }
+ goto force_ro;
+ }
+ return 0;
- *root = lelb_to_cpu(fset->rootDirectoryICB.extLocation);
+force_ro:
+ if (!sb_rdonly(sb))
+ return -EACCES;
+ UDF_SET_FLAG(sb, UDF_FLAG_RW_INCOMPAT);
+ return 0;
+}
+static int udf_load_fileset(struct super_block *sb, struct fileSetDesc *fset,
+ struct kernel_lb_addr *root)
+{
+ int ret;
+
+ ret = udf_verify_domain_identifier(sb, &fset->domainIdent, "file set");
+ if (ret < 0)
+ return ret;
+
+ *root = lelb_to_cpu(fset->rootDirectoryICB.extLocation);
UDF_SB(sb)->s_serial_number = le16_to_cpu(fset->descTag.tagSerialNum);
udf_debug("Rootdir at block=%u, partition=%u\n",
root->logicalBlockNum, root->partitionReferenceNum);
+ return 0;
}
int udf_compute_nr_groups(struct super_block *sb, u32 partition)
@@ -1364,6 +1397,10 @@ static int udf_load_logicalvol(struct super_block *sb, sector_t block,
goto out_bh;
}
FYI just a little above this there is a 'BUG_ON(ident != TAG_IDENT_LVD)'
that would probably be better coded as 'ret = -EINVAL; goto out_bh;'
+ ret = udf_verify_domain_identifier(sb, &lvd->domainIdent,
+ "logical volume");
+ if (ret)
+ goto out_bh;
ret = udf_sb_alloc_partition_maps(sb, le32_to_cpu(lvd->numPartitionMaps));
if (ret)
goto out_bh;
@@ -2216,9 +2253,9 @@ static int udf_fill_super(struct super_block *sb, void *options, int silent)
UDF_SET_FLAG(sb, UDF_FLAG_RW_INCOMPAT);
}
- if (udf_find_fileset(sb, &fileset, &rootdir)) {
+ ret = udf_find_fileset(sb, &fileset, &rootdir);
+ if (ret < 0) {
Consider making the "No fileset found" warning conditional on ret != -EACCES,
it's a little confusing to see this in the log:
UDF-fs: warning (device loop0): udf_verify_domain_identifier: Descriptor for file set marked write protected. Forcing read only mount.
UDF-fs: warning (device loop0): udf_fill_super: No fileset found
udf_warn(sb, "No fileset found\n");
- ret = -EINVAL;
goto error_out;
}
------------------------------------------------------------------------
Steven J. Magnani "I claim this network for MARS!
www.digidescorp.com Earthling, return my space modulator!"
#include <standard.disclaimer>
