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Commit 9e92f48c authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: check if in-inode xattr is corrupted in ext4_expand_extra_isize_ea() 



We aren't checking to see if the in-inode extended attribute is
corrupted before we try to expand the inode's extra isize fields.

This can lead to potential crashes caused by the BUG_ON() check in
ext4_xattr_shift_entries().

Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 243d5067

fs/ext4/xattr.c

+28 −4
Original line number Diff line number Diff line
@@ -230,6 +230,27 @@ ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh) 
	return error;

}



static int

__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,

			 void *end, const char *function, unsigned int line)

{

	struct ext4_xattr_entry *entry = IFIRST(header);

	int error = -EFSCORRUPTED;



	if (((void *) header >= end) ||

	    (header->h_magic != le32_to_cpu(EXT4_XATTR_MAGIC)))

		goto errout;

	error = ext4_xattr_check_names(entry, end, entry);

errout:

	if (error)

		__ext4_error_inode(inode, function, line, 0,

				   "corrupted in-inode xattr");

	return error;

}



#define xattr_check_inode(inode, header, end) \

	__xattr_check_inode((inode), (header), (end), __func__, __LINE__)



static inline int

ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)

{
@@ -341,7 +362,7 @@ ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name, 
	header = IHDR(inode, raw_inode);

	entry = IFIRST(header);

	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;

	error = ext4_xattr_check_names(entry, end, entry);

	error = xattr_check_inode(inode, header, end);

	if (error)

		goto cleanup;

	error = ext4_xattr_find_entry(&entry, name_index, name,
@@ -477,7 +498,7 @@ ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size) 
	raw_inode = ext4_raw_inode(&iloc);

	header = IHDR(inode, raw_inode);

	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;

	error = ext4_xattr_check_names(IFIRST(header), end, IFIRST(header));

	error = xattr_check_inode(inode, header, end);

	if (error)

		goto cleanup;

	error = ext4_xattr_list_entries(dentry, IFIRST(header),
@@ -1040,8 +1061,7 @@ int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, 
	is->s.here = is->s.first;

	is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;

	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {

		error = ext4_xattr_check_names(IFIRST(header), is->s.end,

					       IFIRST(header));

		error = xattr_check_inode(inode, header, is->s.end);

		if (error)

			return error;

		/* Find the named attribute. */
@@ -1356,6 +1376,10 @@ int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, 
	last = entry;

	total_ino = sizeof(struct ext4_xattr_ibody_header);



	error = xattr_check_inode(inode, header, end);

	if (error)

		goto cleanup;



	free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);

	if (free >= new_extra_isize) {

		entry = IFIRST(header);