From: Theodore Ts'o <tytso@xxxxxxx> 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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(). [js] use EIO instead of undefined EFSCORRUPTED in 3.12 Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Cc: Julia Lawall <julia.lawall@xxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- fs/ext4/xattr.c | 32 ++++++++++++++++++++++++++++---- 1 file changed, 28 insertions(+), 4 deletions(-) diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index e5835f6e1466..4e7384b7608e 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -233,6 +233,27 @@ 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 = -EIO; + + 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) { @@ -343,7 +364,7 @@ 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, @@ -471,7 +492,7 @@ 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), @@ -986,8 +1007,7 @@ 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. */ @@ -1284,6 +1304,10 @@ 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); -- 2.12.2