From 2dee5aac05565933c5bf6ad4acd4f9bcd6ea2ff7 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 29 Aug 2019 14:11:54 +0200 Subject: [PATCH] udf: Verify domain identifier fields 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. Tested-by: Steven J. Magnani Reviewed-by: Steven J. Magnani Signed-off-by: Jan Kara --- 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 56da1e1680ea..9e72a9e98ab3 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 *); @@ -775,28 +775,27 @@ 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 (fileset->logicalBlockNum == 0xFFFFFFFF && + fileset->partitionReferenceNum == 0xFFFF) + return -EINVAL; - 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); - - 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; } /* @@ -952,19 +951,53 @@ 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) { - 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; + +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) @@ -1375,6 +1408,10 @@ static int udf_load_logicalvol(struct super_block *sb, sector_t block, 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; @@ -2227,9 +2264,9 @@ 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) { udf_warn(sb, "No fileset found\n"); - ret = -EINVAL; goto error_out; }