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Commit 0e5cc9a4 authored by Jan Kara's avatar Jan Kara
Browse files

udf: Check path length when reading symlink 



Symlink reading code does not check whether the resulting path fits into
the page provided by the generic code. This isn't as easy as just
checking the symlink size because of various encoding conversions we
perform on path. So we have to check whether there is still enough space
in the buffer on the fly.

CC: stable@vger.kernel.org
Reported-by: default avatarCarl Henrik Lunde <chlunde@ping.uio.no>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent a1d47b26

fs/udf/dir.c

+2 −1
Original line number Diff line number Diff line
@@ -167,7 +167,8 @@ static int udf_readdir(struct file *file, struct dir_context *ctx) 
			continue;

		}



		flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);

		flen = udf_get_filename(dir->i_sb, nameptr, lfi, fname,

					UDF_NAME_LEN);

		if (!flen)

			continue;

fs/udf/namei.c

+2 −1
Original line number Diff line number Diff line
@@ -233,7 +233,8 @@ static struct fileIdentDesc *udf_find_entry(struct inode *dir, 
		if (!lfi)

			continue;



		flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);

		flen = udf_get_filename(dir->i_sb, nameptr, lfi, fname,

					UDF_NAME_LEN);

		if (flen && udf_match(flen, fname, child->len, child->name))

			goto out_ok;

	}

fs/udf/symlink.c

+26 −5
Original line number Diff line number Diff line
@@ -30,13 +30,16 @@ 
#include <linux/buffer_head.h>

#include "udf_i.h"



static void udf_pc_to_char(struct super_block *sb, unsigned char *from,

			   int fromlen, unsigned char *to)

static int udf_pc_to_char(struct super_block *sb, unsigned char *from,

			  int fromlen, unsigned char *to, int tolen)

{

	struct pathComponent *pc;

	int elen = 0;

	int comp_len;

	unsigned char *p = to;



	/* Reserve one byte for terminating \0 */

	tolen--;

	while (elen < fromlen) {

		pc = (struct pathComponent *)(from + elen);

		switch (pc->componentType) {
@@ -49,22 +52,37 @@ static void udf_pc_to_char(struct super_block *sb, unsigned char *from, 
				break;

			/* Fall through */

		case 2:

			if (tolen == 0)

				return -ENAMETOOLONG;

			p = to;

			*p++ = '/';

			tolen--;

			break;

		case 3:

			if (tolen < 3)

				return -ENAMETOOLONG;

			memcpy(p, "../", 3);

			p += 3;

			tolen -= 3;

			break;

		case 4:

			if (tolen < 2)

				return -ENAMETOOLONG;

			memcpy(p, "./", 2);

			p += 2;

			tolen -= 2;

			/* that would be . - just ignore */

			break;

		case 5:

			p += udf_get_filename(sb, pc->componentIdent, p,

					      pc->lengthComponentIdent);

			comp_len = udf_get_filename(sb, pc->componentIdent,

						    pc->lengthComponentIdent,

						    p, tolen);

			p += comp_len;

			tolen -= comp_len;

			if (tolen == 0)

				return -ENAMETOOLONG;

			*p++ = '/';

			tolen--;

			break;

		}

		elen += sizeof(struct pathComponent) + pc->lengthComponentIdent;
@@ -73,6 +91,7 @@ static void udf_pc_to_char(struct super_block *sb, unsigned char *from, 
		p[-1] = '\0';

	else

		p[0] = '\0';

	return 0;

}



static int udf_symlink_filler(struct file *file, struct page *page)
@@ -108,8 +127,10 @@ static int udf_symlink_filler(struct file *file, struct page *page) 
		symlink = bh->b_data;

	}



	udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p);

	err = udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p, PAGE_SIZE);

	brelse(bh);

	if (err)

		goto out_unlock_inode;



	up_read(&iinfo->i_data_sem);

	SetPageUptodate(page);

fs/udf/udfdecl.h

+2 −1
Original line number Diff line number Diff line
@@ -211,7 +211,8 @@ udf_get_lb_pblock(struct super_block *sb, struct kernel_lb_addr *loc, 
}



/* unicode.c */

extern int udf_get_filename(struct super_block *, uint8_t *, uint8_t *, int);

extern int udf_get_filename(struct super_block *, uint8_t *, int, uint8_t *,

			    int);

extern int udf_put_filename(struct super_block *, const uint8_t *, uint8_t *,

			    int);

extern int udf_build_ustr(struct ustr *, dstring *, int);

fs/udf/unicode.c

+16 −12
Original line number Diff line number Diff line
@@ -28,7 +28,8 @@ 


#include "udf_sb.h"



static int udf_translate_to_linux(uint8_t *, uint8_t *, int, uint8_t *, int);

static int udf_translate_to_linux(uint8_t *, int, uint8_t *, int, uint8_t *,

				  int);



static int udf_char_to_ustr(struct ustr *dest, const uint8_t *src, int strlen)

{
@@ -333,8 +334,8 @@ static int udf_NLStoCS0(struct nls_table *nls, dstring *ocu, struct ustr *uni, 
	return u_len + 1;

}



int udf_get_filename(struct super_block *sb, uint8_t *sname, uint8_t *dname,

		     int flen)

int udf_get_filename(struct super_block *sb, uint8_t *sname, int slen,

		     uint8_t *dname, int dlen)

{

	struct ustr *filename, *unifilename;

	int len = 0;
@@ -347,7 +348,7 @@ int udf_get_filename(struct super_block *sb, uint8_t *sname, uint8_t *dname, 
	if (!unifilename)

		goto out1;



	if (udf_build_ustr_exact(unifilename, sname, flen))

	if (udf_build_ustr_exact(unifilename, sname, slen))

		goto out2;



	if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
@@ -366,7 +367,8 @@ int udf_get_filename(struct super_block *sb, uint8_t *sname, uint8_t *dname, 
	} else

		goto out2;



	len = udf_translate_to_linux(dname, filename->u_name, filename->u_len,

	len = udf_translate_to_linux(dname, dlen,

				     filename->u_name, filename->u_len,

				     unifilename->u_name, unifilename->u_len);

out2:

	kfree(unifilename);
@@ -403,10 +405,12 @@ int udf_put_filename(struct super_block *sb, const uint8_t *sname, 
#define EXT_MARK		'.'

#define CRC_MARK		'#'

#define EXT_SIZE 		5

/* Number of chars we need to store generated CRC to make filename unique */

#define CRC_LEN			5



static int udf_translate_to_linux(uint8_t *newName, uint8_t *udfName,

				  int udfLen, uint8_t *fidName,

				  int fidNameLen)

static int udf_translate_to_linux(uint8_t *newName, int newLen,

				  uint8_t *udfName, int udfLen,

				  uint8_t *fidName, int fidNameLen)

{

	int index, newIndex = 0, needsCRC = 0;

	int extIndex = 0, newExtIndex = 0, hasExt = 0;
@@ -439,7 +443,7 @@ static int udf_translate_to_linux(uint8_t *newName, uint8_t *udfName, 
					newExtIndex = newIndex;

				}

			}

			if (newIndex < 256)

			if (newIndex < newLen)

				newName[newIndex++] = curr;

			else

				needsCRC = 1;
@@ -467,13 +471,13 @@ static int udf_translate_to_linux(uint8_t *newName, uint8_t *udfName, 
				}

				ext[localExtIndex++] = curr;

			}

			maxFilenameLen = 250 - localExtIndex;

			maxFilenameLen = newLen - CRC_LEN - localExtIndex;

			if (newIndex > maxFilenameLen)

				newIndex = maxFilenameLen;

			else

				newIndex = newExtIndex;

		} else if (newIndex > 250)

			newIndex = 250;

		} else if (newIndex > newLen - CRC_LEN)

			newIndex = newLen - CRC_LEN;

		newName[newIndex++] = CRC_MARK;

		valueCRC = crc_itu_t(0, fidName, fidNameLen);

		newName[newIndex++] = hex_asc_upper_hi(valueCRC >> 8);