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Message-ID: <lsq.1424137613.350884128@decadent.org.uk>
Date: Tue, 17 Feb 2015 01:46:53 +0000
From: Ben Hutchings <ben@...adent.org.uk>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC: akpm@...ux-foundation.org, "Jan Kara" <jack@...e.cz>,
"Carl Henrik Lunde" <chlunde@...g.uio.no>
Subject: [PATCH 3.2 070/152] udf: Check path length when reading symlink
3.2.67-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Jan Kara <jack@...e.cz>
commit 0e5cc9a40ada6046e6bc3bdfcd0c0d7e4b706b14 upstream.
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.
Reported-by: Carl Henrik Lunde <chlunde@...g.uio.no>
Signed-off-by: Jan Kara <jack@...e.cz>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
fs/udf/dir.c | 3 ++-
fs/udf/namei.c | 3 ++-
fs/udf/symlink.c | 31 ++++++++++++++++++++++++++-----
fs/udf/udfdecl.h | 3 ++-
fs/udf/unicode.c | 28 ++++++++++++++++------------
5 files changed, 48 insertions(+), 20 deletions(-)
--- a/fs/udf/dir.c
+++ b/fs/udf/dir.c
@@ -163,7 +163,8 @@ static int do_udf_readdir(struct inode *
struct kernel_lb_addr tloc = lelb_to_cpu(cfi.icb.extLocation);
iblock = udf_get_lb_pblock(dir->i_sb, &tloc, 0);
- flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
+ flen = udf_get_filename(dir->i_sb, nameptr, lfi, fname,
+ UDF_NAME_LEN);
dt_type = DT_UNKNOWN;
}
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -235,7 +235,8 @@ static struct fileIdentDesc *udf_find_en
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;
}
--- a/fs/udf/symlink.c
+++ b/fs/udf/symlink.c
@@ -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_
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_
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 fil
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);
--- a/fs/udf/udfdecl.h
+++ b/fs/udf/udfdecl.h
@@ -207,7 +207,8 @@ udf_get_lb_pblock(struct super_block *sb
}
/* 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);
--- a/fs/udf/unicode.c
+++ b/fs/udf/unicode.c
@@ -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 @@ try_again:
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
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
} 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
#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;
@@ -440,7 +444,7 @@ static int udf_translate_to_linux(uint8_
newExtIndex = newIndex;
}
}
- if (newIndex < 256)
+ if (newIndex < newLen)
newName[newIndex++] = curr;
else
needsCRC = 1;
@@ -468,13 +472,13 @@ static int udf_translate_to_linux(uint8_
}
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++] = hexChar[(valueCRC & 0xf000) >> 12];
--
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