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

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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: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2016-03-22 16:13:15 -04:00
parent 243d506785
commit 9e92f48c34
1 changed files with 28 additions and 4 deletions
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32
fs/ext4/xattr.c
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@ -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 @@ retry:
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);