Commit ec81aecb authored by Amerigo Wang's avatar Amerigo Wang Committed by Linus Torvalds
Browse files

hfs: fix a potential buffer overflow 



A specially-crafted Hierarchical File System (HFS) filesystem could cause
a buffer overflow to occur in a process's kernel stack during a memcpy()
call within the hfs_bnode_read() function (at fs/hfs/bnode.c:24).  The
attacker can provide the source buffer and length, and the destination
buffer is a local variable of a fixed length.  This local variable (passed
as "&entry" from fs/hfs/dir.c:112 and allocated on line 60) is stored in
the stack frame of hfs_bnode_read()'s caller, which is hfs_readdir().
Because the hfs_readdir() function executes upon any attempt to read a
directory on the filesystem, it gets called whenever a user attempts to
inspect any filesystem contents.

[amwang@redhat.com: modify this patch and fix coding style problems]
Signed-off-by: default avatarWANG Cong <amwang@redhat.com>
Cc: Eugene Teo <eteo@redhat.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Dave Anderson <anderson@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4b731d50

fs/hfs/catalog.c

+4 −0
Original line number Original line Diff line number Diff line
@@ -289,6 +289,10 @@ int hfs_cat_move(u32 cnid, struct inode *src_dir, struct qstr *src_name, 
	err = hfs_brec_find(&src_fd);

	err = hfs_brec_find(&src_fd);

	if (err)

	if (err)

		goto out;

		goto out;

	if (src_fd.entrylength > sizeof(entry) || src_fd.entrylength < 0) {

		err = -EIO;

		goto out;

	}





	hfs_bnode_read(src_fd.bnode, &entry, src_fd.entryoffset,

	hfs_bnode_read(src_fd.bnode, &entry, src_fd.entryoffset,

			    src_fd.entrylength);

			    src_fd.entrylength);

fs/hfs/dir.c

+11 −0
Original line number Original line Diff line number Diff line
@@ -79,6 +79,11 @@ static int hfs_readdir(struct file *filp, void *dirent, filldir_t filldir) 
		filp->f_pos++;

		filp->f_pos++;

		/* fall through */

		/* fall through */

	case 1:

	case 1:

		if (fd.entrylength > sizeof(entry) || fd.entrylength < 0) {

			err = -EIO;

			goto out;

		}



		hfs_bnode_read(fd.bnode, &entry, fd.entryoffset, fd.entrylength);

		hfs_bnode_read(fd.bnode, &entry, fd.entryoffset, fd.entrylength);

		if (entry.type != HFS_CDR_THD) {

		if (entry.type != HFS_CDR_THD) {

			printk(KERN_ERR "hfs: bad catalog folder thread\n");

			printk(KERN_ERR "hfs: bad catalog folder thread\n");
@@ -109,6 +114,12 @@ static int hfs_readdir(struct file *filp, void *dirent, filldir_t filldir) 
			err = -EIO;

			err = -EIO;

			goto out;

			goto out;

		}

		}



		if (fd.entrylength > sizeof(entry) || fd.entrylength < 0) {

			err = -EIO;

			goto out;

		}



		hfs_bnode_read(fd.bnode, &entry, fd.entryoffset, fd.entrylength);

		hfs_bnode_read(fd.bnode, &entry, fd.entryoffset, fd.entrylength);

		type = entry.type;

		type = entry.type;

		len = hfs_mac2asc(sb, strbuf, &fd.key->cat.CName);

		len = hfs_mac2asc(sb, strbuf, &fd.key->cat.CName);

fs/hfs/super.c

+6 −1
Original line number Original line Diff line number Diff line
@@ -409,8 +409,13 @@ static int hfs_fill_super(struct super_block *sb, void *data, int silent) 
	/* try to get the root inode */

	/* try to get the root inode */

	hfs_find_init(HFS_SB(sb)->cat_tree, &fd);

	hfs_find_init(HFS_SB(sb)->cat_tree, &fd);

	res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd);

	res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd);

	if (!res)

	if (!res) {

		if (fd.entrylength > sizeof(rec) || fd.entrylength < 0) {

			res =  -EIO;

			goto bail;

		}

		hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength);

		hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength);

	}

	if (res) {

	if (res) {

		hfs_find_exit(&fd);

		hfs_find_exit(&fd);

		goto bail_no_root;

		goto bail_no_root;

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