From 3980bd3b406addb327d858aebd19e229ea340b9a Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sun, 31 Jul 2016 23:38:36 -0400 Subject: ext4: reserve xattr index for the Hurd The Hurd is using inode fields which restricts it from using more advanced ext4 file system features, due to design choices made over a decade ago. By giving the Hurd an extended attribute index field we allow it to move the translator and author fields out of the core inode fields, and hopefully we can get rid of ugly hacks such as EXT4_OS_HURD and EXT4_MOUNT2_HURD_COMPAT somday. For more information please see: https://summerofcode.withgoogle.com/projects/#5869799859027968 Signed-off-by: Theodore Ts'o diff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h index 69dd3e6..a92e783 100644 --- a/fs/ext4/xattr.h +++ b/fs/ext4/xattr.h @@ -24,6 +24,7 @@ #define EXT4_XATTR_INDEX_SYSTEM 7 #define EXT4_XATTR_INDEX_RICHACL 8 #define EXT4_XATTR_INDEX_ENCRYPTION 9 +#define EXT4_XATTR_INDEX_HURD 10 /* Reserved for Hurd */ struct ext4_xattr_header { __le32 h_magic; /* magic number for identification */ -- cgit v0.10.2 From 829fa70dddadf9dd041d62b82cd7cea63943899d Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Mon, 1 Aug 2016 00:51:02 -0400 Subject: ext4: validate that metadata blocks do not overlap superblock A number of fuzzing failures seem to be caused by allocation bitmaps or other metadata blocks being pointed at the superblock. This can cause kernel BUG or WARNings once the superblock is overwritten, so validate the group descriptor blocks to make sure this doesn't happen. Cc: stable@vger.kernel.org Signed-off-by: Theodore Ts'o diff --git a/fs/ext4/super.c b/fs/ext4/super.c index c13a4e4..da3146e 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2211,6 +2211,7 @@ void ext4_group_desc_csum_set(struct super_block *sb, __u32 block_group, /* Called at mount-time, super-block is locked */ static int ext4_check_descriptors(struct super_block *sb, + ext4_fsblk_t sb_block, ext4_group_t *first_not_zeroed) { struct ext4_sb_info *sbi = EXT4_SB(sb); @@ -2241,6 +2242,11 @@ static int ext4_check_descriptors(struct super_block *sb, grp = i; block_bitmap = ext4_block_bitmap(sb, gdp); + if (block_bitmap == sb_block) { + ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: " + "Block bitmap for group %u overlaps " + "superblock", i); + } if (block_bitmap < first_block || block_bitmap > last_block) { ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: " "Block bitmap for group %u not in group " @@ -2248,6 +2254,11 @@ static int ext4_check_descriptors(struct super_block *sb, return 0; } inode_bitmap = ext4_inode_bitmap(sb, gdp); + if (inode_bitmap == sb_block) { + ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: " + "Inode bitmap for group %u overlaps " + "superblock", i); + } if (inode_bitmap < first_block || inode_bitmap > last_block) { ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: " "Inode bitmap for group %u not in group " @@ -2255,6 +2266,11 @@ static int ext4_check_descriptors(struct super_block *sb, return 0; } inode_table = ext4_inode_table(sb, gdp); + if (inode_table == sb_block) { + ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: " + "Inode table for group %u overlaps " + "superblock", i); + } if (inode_table < first_block || inode_table + sbi->s_itb_per_group - 1 > last_block) { ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: " @@ -3757,7 +3773,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) goto failed_mount2; } } - if (!ext4_check_descriptors(sb, &first_not_zeroed)) { + if (!ext4_check_descriptors(sb, logical_sb_block, &first_not_zeroed)) { ext4_msg(sb, KERN_ERR, "group descriptors corrupted!"); ret = -EFSCORRUPTED; goto failed_mount2; -- cgit v0.10.2 From d0141191a20289f8955c1e03dad08e42e6f71ca9 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 11 Aug 2016 11:50:30 -0400 Subject: ext4: fix xattr shifting when expanding inodes The code in ext4_expand_extra_isize_ea() treated new_extra_isize argument sometimes as the desired target i_extra_isize and sometimes as the amount by which we need to grow current i_extra_isize. These happen to coincide when i_extra_isize is 0 which used to be the common case and so nobody noticed this until recently when we added i_projid to the inode and so i_extra_isize now needs to grow from 28 to 32 bytes. The result of these bugs was that we sometimes unnecessarily decided to move xattrs out of inode even if there was enough space and we often ended up corrupting in-inode xattrs because arguments to ext4_xattr_shift_entries() were just wrong. This could demonstrate itself as BUG_ON in ext4_xattr_shift_entries() triggering. Fix the problem by introducing new isize_diff variable and use it where appropriate. CC: stable@vger.kernel.org # 4.4.x Reported-by: Dave Chinner Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index 39e9cfb..cb1d7b4 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -1353,11 +1353,13 @@ int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, size_t min_offs, free; int total_ino; void *base, *start, *end; - int extra_isize = 0, error = 0, tried_min_extra_isize = 0; + int error = 0, tried_min_extra_isize = 0; int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize); + int isize_diff; /* How much do we need to grow i_extra_isize */ down_write(&EXT4_I(inode)->xattr_sem); retry: + isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize; if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) { up_write(&EXT4_I(inode)->xattr_sem); return 0; @@ -1382,7 +1384,7 @@ retry: goto cleanup; free = ext4_xattr_free_space(last, &min_offs, base, &total_ino); - if (free >= new_extra_isize) { + if (free >= isize_diff) { entry = IFIRST(header); ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize - new_extra_isize, (void *)raw_inode + @@ -1414,7 +1416,7 @@ retry: end = bh->b_data + bh->b_size; min_offs = end - base; free = ext4_xattr_free_space(first, &min_offs, base, NULL); - if (free < new_extra_isize) { + if (free < isize_diff) { if (!tried_min_extra_isize && s_min_extra_isize) { tried_min_extra_isize++; new_extra_isize = s_min_extra_isize; @@ -1428,7 +1430,7 @@ retry: free = inode->i_sb->s_blocksize; } - while (new_extra_isize > 0) { + while (isize_diff > 0) { size_t offs, size, entry_size; struct ext4_xattr_entry *small_entry = NULL; struct ext4_xattr_info i = { @@ -1459,7 +1461,7 @@ retry: EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) + EXT4_XATTR_LEN(last->e_name_len); if (total_size <= free && total_size < min_total_size) { - if (total_size < new_extra_isize) { + if (total_size < isize_diff) { small_entry = last; } else { entry = last; @@ -1516,20 +1518,19 @@ retry: goto cleanup; entry = IFIRST(header); - if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize) - shift_bytes = new_extra_isize; + if (entry_size + EXT4_XATTR_SIZE(size) >= isize_diff) + shift_bytes = isize_diff; else shift_bytes = entry_size + size; /* Adjust the offsets and shift the remaining entries ahead */ - ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize - - shift_bytes, (void *)raw_inode + - EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes, + ext4_xattr_shift_entries(entry, -shift_bytes, + (void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE + + EXT4_I(inode)->i_extra_isize + shift_bytes, (void *)header, total_ino - entry_size, inode->i_sb->s_blocksize); - extra_isize += shift_bytes; - new_extra_isize -= shift_bytes; - EXT4_I(inode)->i_extra_isize = extra_isize; + isize_diff -= shift_bytes; + EXT4_I(inode)->i_extra_isize += shift_bytes; i.name = b_entry_name; i.value = buffer; -- cgit v0.10.2 From 418c12d08dc64a45107c467ec1ba29b5e69b0715 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 11 Aug 2016 11:58:32 -0400 Subject: ext4: fix xattr shifting when expanding inodes part 2 When multiple xattrs need to be moved out of inode, we did not properly recompute total size of xattr headers in the inode and the new header position. Thus when moving the second and further xattr we asked ext4_xattr_shift_entries() to move too much and from the wrong place, resulting in possible xattr value corruption or general memory corruption. CC: stable@vger.kernel.org # 4.4.x Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index cb1d7b4..b18b1ff 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -1516,6 +1516,7 @@ retry: error = ext4_xattr_ibody_set(handle, inode, &i, is); if (error) goto cleanup; + total_ino -= entry_size; entry = IFIRST(header); if (entry_size + EXT4_XATTR_SIZE(size) >= isize_diff) @@ -1526,11 +1527,11 @@ retry: ext4_xattr_shift_entries(entry, -shift_bytes, (void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE + EXT4_I(inode)->i_extra_isize + shift_bytes, - (void *)header, total_ino - entry_size, - inode->i_sb->s_blocksize); + (void *)header, total_ino, inode->i_sb->s_blocksize); isize_diff -= shift_bytes; EXT4_I(inode)->i_extra_isize += shift_bytes; + header = IHDR(inode, raw_inode); i.name = b_entry_name; i.value = buffer; -- cgit v0.10.2 From 443a8c41cd49de66a3fda45b32b9860ea0292b84 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 11 Aug 2016 12:00:01 -0400 Subject: ext4: properly align shifted xattrs when expanding inodes We did not count with the padding of xattr value when computing desired shift of xattrs in the inode when expanding i_extra_isize. As a result we could create unaligned start of inline xattrs. Account for alignment properly. CC: stable@vger.kernel.org # 4.4.x- Signed-off-by: Jan Kara diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index b18b1ff..c893f00 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -1522,7 +1522,7 @@ retry: if (entry_size + EXT4_XATTR_SIZE(size) >= isize_diff) shift_bytes = isize_diff; else - shift_bytes = entry_size + size; + shift_bytes = entry_size + EXT4_XATTR_SIZE(size); /* Adjust the offsets and shift the remaining entries ahead */ ext4_xattr_shift_entries(entry, -shift_bytes, (void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE + -- cgit v0.10.2 From 2e81a4eeedcaa66e35f58b81e0755b87057ce392 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 11 Aug 2016 12:38:55 -0400 Subject: ext4: avoid deadlock when expanding inode size When we need to move xattrs into external xattr block, we call ext4_xattr_block_set() from ext4_expand_extra_isize_ea(). That may end up calling ext4_mark_inode_dirty() again which will recurse back into the inode expansion code leading to deadlocks. Protect from recursion using EXT4_STATE_NO_EXPAND inode flag and move its management into ext4_expand_extra_isize_ea() since its manipulation is safe there (due to xattr_sem) from possible races with ext4_xattr_set_handle() which plays with it as well. CC: stable@vger.kernel.org # 4.4.x Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 5a6277d..13c95b2 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5466,8 +5466,6 @@ int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode) sbi->s_want_extra_isize, iloc, handle); if (ret) { - ext4_set_inode_state(inode, - EXT4_STATE_NO_EXPAND); if (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count)) { ext4_warning(inode->i_sb, diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index c893f00..2eb935c 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -1358,12 +1358,14 @@ int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, int isize_diff; /* How much do we need to grow i_extra_isize */ down_write(&EXT4_I(inode)->xattr_sem); + /* + * Set EXT4_STATE_NO_EXPAND to avoid recursion when marking inode dirty + */ + ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); retry: isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize; - if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) { - up_write(&EXT4_I(inode)->xattr_sem); - return 0; - } + if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) + goto out; header = IHDR(inode, raw_inode); entry = IFIRST(header); @@ -1392,8 +1394,7 @@ retry: (void *)header, total_ino, inode->i_sb->s_blocksize); EXT4_I(inode)->i_extra_isize = new_extra_isize; - error = 0; - goto cleanup; + goto out; } /* @@ -1553,6 +1554,8 @@ retry: kfree(bs); } brelse(bh); +out: + ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); up_write(&EXT4_I(inode)->xattr_sem); return 0; @@ -1564,6 +1567,10 @@ cleanup: kfree(is); kfree(bs); brelse(bh); + /* + * We deliberately leave EXT4_STATE_NO_EXPAND set here since inode + * size expansion failed. + */ up_write(&EXT4_I(inode)->xattr_sem); return error; } -- cgit v0.10.2