4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Theodore Ts'o <tytso@xxxxxxx>
commit 9e92f48c34eb2b9af9d12f892e2fe1fce5e8ce35 upstream.
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@xxxxxxx>
Cc: Julia Lawall <julia.lawall@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/xattr.c | 32 ++++++++++++++++++++++++++++----
1 file changed, 28 insertions(+), 4 deletions(-)
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -233,6 +233,27 @@ ext4_xattr_check_block(struct inode *ino
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)
{
@@ -344,7 +365,7 @@ ext4_xattr_ibody_get(struct inode *inode
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,
@@ -475,7 +496,7 @@ ext4_xattr_ibody_list(struct dentry *den
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),
@@ -991,8 +1012,7 @@ int ext4_xattr_ibody_find(struct inode *
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. */
@@ -1293,6 +1313,10 @@ 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 >= isize_diff) {
entry = IFIRST(header);