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[3.13.y-ckt,stable] Patch "udf: Check path length when reading symlink" has been added to staging queue

Message ID 1424305695-13623-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa Feb. 19, 2015, 12:28 a.m. UTC 
This is a note to let you know that I have just added a patch titled

    udf: Check path length when reading symlink

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt16.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

From 4deeac5fefeb24e10378c93441c81dcdefabd5e9 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Thu, 18 Dec 2014 22:37:50 +0100
Subject: udf: Check path length when reading symlink

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@ping.uio.no>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 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(-)

--
1.9.1
diff mbox

Patch

diff --git a/fs/udf/dir.c b/fs/udf/dir.c
index a012c51..a7690b4 100644
--- a/fs/udf/dir.c
+++ b/fs/udf/dir.c
@@ -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;

diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index 5f6fc17..6de89a4 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -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;
 	}
diff --git a/fs/udf/symlink.c b/fs/udf/symlink.c
index d89f324..2d0c372 100644
--- 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_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);
diff --git a/fs/udf/udfdecl.h b/fs/udf/udfdecl.h
index be7dabb..55d1d19 100644
--- a/fs/udf/udfdecl.h
+++ b/fs/udf/udfdecl.h
@@ -201,7 +201,8 @@  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);
diff --git a/fs/udf/unicode.c b/fs/udf/unicode.c
index 44b815e..d29c06f 100644
--- 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 *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;
@@ -440,7 +444,7 @@  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;
@@ -468,13 +472,13 @@  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++] = hexChar[(valueCRC & 0xf000) >> 12];