// SPDX-License-Identifier: GPL-2.0-only/* * misc.c * * PURPOSE *	Miscellaneous routines for the OSTA-UDF(tm) filesystem. * * COPYRIGHT *  (C) 1998 Dave Boynton *  (C) 1998-2004 Ben Fennema *  (C) 1999-2000 Stelias Computing Inc * * HISTORY * *  04/19/99 blf  partial support for reading/writing specific EA's */ #include "udfdecl.h" #include <linux/fs.h>#include <linux/string.h>#include <linux/crc-itu-t.h> #include "udf_i.h"#include "udf_sb.h" struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,					   uint32_t type, uint8_t loc){	uint8_t *ea = NULL, *ad = NULL;	int offset;	uint16_t crclen;	struct udf_inode_info *iinfo = UDF_I(inode); 	ea = iinfo->i_data;	if (iinfo->i_lenEAttr) {		ad = iinfo->i_data + iinfo->i_lenEAttr;	} else {		ad = ea;		size += sizeof(struct extendedAttrHeaderDesc);	} 	offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -		iinfo->i_lenAlloc; 	/* TODO - Check for FreeEASpace */ 	if (loc & 0x01 && offset >= size) {		struct extendedAttrHeaderDesc *eahd;		eahd = (struct extendedAttrHeaderDesc *)ea; 		if (iinfo->i_lenAlloc)			memmove(&ad[size], ad, iinfo->i_lenAlloc); 		if (iinfo->i_lenEAttr) {			/* check checksum/crc */			if (eahd->descTag.tagIdent !=					cpu_to_le16(TAG_IDENT_EAHD) ||			    le32_to_cpu(eahd->descTag.tagLocation) !=					iinfo->i_location.logicalBlockNum)				return NULL;		} else {			struct udf_sb_info *sbi = UDF_SB(inode->i_sb); 			size -= sizeof(struct extendedAttrHeaderDesc);			iinfo->i_lenEAttr +=				sizeof(struct extendedAttrHeaderDesc);			eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);			if (sbi->s_udfrev >= 0x0200)				eahd->descTag.descVersion = cpu_to_le16(3);			else				eahd->descTag.descVersion = cpu_to_le16(2);			eahd->descTag.tagSerialNum =					cpu_to_le16(sbi->s_serial_number);			eahd->descTag.tagLocation = cpu_to_le32(					iinfo->i_location.logicalBlockNum);			eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);			eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);		} 		offset = iinfo->i_lenEAttr;		if (type < 2048) {			if (le32_to_cpu(eahd->appAttrLocation) <					iinfo->i_lenEAttr) {				uint32_t aal =					le32_to_cpu(eahd->appAttrLocation);				memmove(&ea[offset - aal + size],					&ea[aal], offset - aal);				offset -= aal;				eahd->appAttrLocation =						cpu_to_le32(aal + size);			}			if (le32_to_cpu(eahd->impAttrLocation) <					iinfo->i_lenEAttr) {				uint32_t ial =					le32_to_cpu(eahd->impAttrLocation);				memmove(&ea[offset - ial + size],					&ea[ial], offset - ial);				offset -= ial;				eahd->impAttrLocation =						cpu_to_le32(ial + size);			}		} else if (type < 65536) {			if (le32_to_cpu(eahd->appAttrLocation) <					iinfo->i_lenEAttr) {				uint32_t aal =					le32_to_cpu(eahd->appAttrLocation);				memmove(&ea[offset - aal + size],					&ea[aal], offset - aal);				offset -= aal;				eahd->appAttrLocation =						cpu_to_le32(aal + size);			}		}		/* rewrite CRC + checksum of eahd */		crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(struct tag);		eahd->descTag.descCRCLength = cpu_to_le16(crclen);		eahd->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)eahd +						sizeof(struct tag), crclen));		eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);		iinfo->i_lenEAttr += size;		return (struct genericFormat *)&ea[offset];	} 	return NULL;} struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type,					   uint8_t subtype){	struct genericFormat *gaf;	uint8_t *ea = NULL;	uint32_t offset;	struct udf_inode_info *iinfo = UDF_I(inode); 	ea = iinfo->i_data; 	if (iinfo->i_lenEAttr) {		struct extendedAttrHeaderDesc *eahd;		eahd = (struct extendedAttrHeaderDesc *)ea; 		/* check checksum/crc */		if (eahd->descTag.tagIdent !=				cpu_to_le16(TAG_IDENT_EAHD) ||		    le32_to_cpu(eahd->descTag.tagLocation) !=				iinfo->i_location.logicalBlockNum)			return NULL; 		if (type < 2048)			offset = sizeof(struct extendedAttrHeaderDesc);		else if (type < 65536)			offset = le32_to_cpu(eahd->impAttrLocation);		else			offset = le32_to_cpu(eahd->appAttrLocation); 		while (offset + sizeof(*gaf) < iinfo->i_lenEAttr) {			uint32_t attrLength; 			gaf = (struct genericFormat *)&ea[offset];			attrLength = le32_to_cpu(gaf->attrLength); 			/* Detect undersized elements and buffer overflows */			if ((attrLength < sizeof(*gaf)) ||			    (attrLength > (iinfo->i_lenEAttr - offset)))				break; 			if (le32_to_cpu(gaf->attrType) == type &&					gaf->attrSubtype == subtype)				return gaf;			else				offset += attrLength;		}	} 	return NULL;} /* * udf_read_tagged * * PURPOSE *	Read the first block of a tagged descriptor. * * HISTORY *	July 1, 1997 - Andrew E. Mileski *	Written, tested, and released. */struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,				    uint32_t location, uint16_t *ident){	struct tag *tag_p;	struct buffer_head *bh = NULL;	u8 checksum; 	/* Read the block */	if (block == 0xFFFFFFFF)		return NULL; 	bh = sb_bread(sb, block);	if (!bh) {		udf_err(sb, "read failed, block=%u, location=%u\n",			block, location);		return NULL;	} 	tag_p = (struct tag *)(bh->b_data); 	*ident = le16_to_cpu(tag_p->tagIdent); 	if (location != le32_to_cpu(tag_p->tagLocation)) {		udf_debug("location mismatch block %u, tag %u != %u\n",			  block, le32_to_cpu(tag_p->tagLocation), location);		goto error_out;	} 	/* Verify the tag checksum */	checksum = udf_tag_checksum(tag_p);	if (checksum != tag_p->tagChecksum) {		udf_err(sb, "tag checksum failed, block %u: 0x%02x != 0x%02x\n",			block, checksum, tag_p->tagChecksum);		goto error_out;	} 	/* Verify the tag version */	if (tag_p->descVersion != cpu_to_le16(0x0002U) &&	    tag_p->descVersion != cpu_to_le16(0x0003U)) {		udf_err(sb, "tag version 0x%04x != 0x0002 || 0x0003, block %u\n",			le16_to_cpu(tag_p->descVersion), block);		goto error_out;	} 	/* Verify the descriptor CRC */	if (le16_to_cpu(tag_p->descCRCLength) + sizeof(struct tag) > sb->s_blocksize) {		udf_err(sb, "block %u: CRC length %u exceeds block size\n",			block, le16_to_cpu(tag_p->descCRCLength));		goto error_out;	}	if (le16_to_cpu(tag_p->descCRC) == crc_itu_t(0,					bh->b_data + sizeof(struct tag),					le16_to_cpu(tag_p->descCRCLength)))		return bh; 	udf_debug("Crc failure block %u: crc = %u, crclen = %u\n", block,		  le16_to_cpu(tag_p->descCRC),		  le16_to_cpu(tag_p->descCRCLength));error_out:	brelse(bh);	return NULL;} struct buffer_head *udf_read_ptagged(struct super_block *sb,				     struct kernel_lb_addr *loc,				     uint32_t offset, uint16_t *ident){	return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),			       loc->logicalBlockNum + offset, ident);} void udf_update_tag(char *data, int length){	struct tag *tptr = (struct tag *)data;	length -= sizeof(struct tag); 	tptr->descCRCLength = cpu_to_le16(length);	tptr->descCRC = cpu_to_le16(crc_itu_t(0, data + sizeof(struct tag), length));	tptr->tagChecksum = udf_tag_checksum(tptr);} void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,		 uint32_t loc, int length){	struct tag *tptr = (struct tag *)data;	tptr->tagIdent = cpu_to_le16(ident);	tptr->descVersion = cpu_to_le16(version);	tptr->tagSerialNum = cpu_to_le16(snum);	tptr->tagLocation = cpu_to_le32(loc);	udf_update_tag(data, length);} u8 udf_tag_checksum(const struct tag *t){	u8 *data = (u8 *)t;	u8 checksum = 0;	int i;	for (i = 0; i < sizeof(struct tag); ++i)		if (i != 4) /* position of checksum */			checksum += data[i];	return checksum;}