ext4: lock the xattr block before checksuming it
commit dac7a4b4b1
upstream.
We must lock the xattr block before calculating or verifying the
checksum in order to avoid spurious checksum failures.
https://bugzilla.kernel.org/show_bug.cgi?id=193661
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
f572ba9a71
commit
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@ -131,31 +131,26 @@ static __le32 ext4_xattr_block_csum(struct inode *inode,
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}
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static int ext4_xattr_block_csum_verify(struct inode *inode,
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sector_t block_nr,
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struct ext4_xattr_header *hdr)
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struct buffer_head *bh)
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{
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if (ext4_has_metadata_csum(inode->i_sb) &&
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(hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
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return 0;
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return 1;
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struct ext4_xattr_header *hdr = BHDR(bh);
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int ret = 1;
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if (ext4_has_metadata_csum(inode->i_sb)) {
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lock_buffer(bh);
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ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
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bh->b_blocknr, hdr));
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unlock_buffer(bh);
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}
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return ret;
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}
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static void ext4_xattr_block_csum_set(struct inode *inode,
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sector_t block_nr,
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struct ext4_xattr_header *hdr)
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{
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if (!ext4_has_metadata_csum(inode->i_sb))
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return;
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hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
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}
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static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
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struct inode *inode,
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struct buffer_head *bh)
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{
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ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
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return ext4_handle_dirty_metadata(handle, inode, bh);
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if (ext4_has_metadata_csum(inode->i_sb))
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BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
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bh->b_blocknr, BHDR(bh));
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}
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static inline const struct xattr_handler *
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@ -218,7 +213,7 @@ ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
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if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
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BHDR(bh)->h_blocks != cpu_to_le32(1))
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return -EFSCORRUPTED;
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if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
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if (!ext4_xattr_block_csum_verify(inode, bh))
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return -EFSBADCRC;
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error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size,
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bh->b_data);
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@ -601,23 +596,22 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
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}
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}
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ext4_xattr_block_csum_set(inode, bh);
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/*
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* Beware of this ugliness: Releasing of xattr block references
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* from different inodes can race and so we have to protect
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* from a race where someone else frees the block (and releases
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* its journal_head) before we are done dirtying the buffer. In
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* nojournal mode this race is harmless and we actually cannot
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* call ext4_handle_dirty_xattr_block() with locked buffer as
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* call ext4_handle_dirty_metadata() with locked buffer as
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* that function can call sync_dirty_buffer() so for that case
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* we handle the dirtying after unlocking the buffer.
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*/
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if (ext4_handle_valid(handle))
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error = ext4_handle_dirty_xattr_block(handle, inode,
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bh);
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error = ext4_handle_dirty_metadata(handle, inode, bh);
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unlock_buffer(bh);
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if (!ext4_handle_valid(handle))
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error = ext4_handle_dirty_xattr_block(handle, inode,
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bh);
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error = ext4_handle_dirty_metadata(handle, inode, bh);
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if (IS_SYNC(inode))
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ext4_handle_sync(handle);
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dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
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@ -846,11 +840,12 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
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ext4_xattr_cache_insert(ext4_mb_cache,
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bs->bh);
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}
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ext4_xattr_block_csum_set(inode, bs->bh);
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unlock_buffer(bs->bh);
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if (error == -EFSCORRUPTED)
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goto bad_block;
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if (!error)
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error = ext4_handle_dirty_xattr_block(handle,
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error = ext4_handle_dirty_metadata(handle,
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inode,
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bs->bh);
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if (error)
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@ -950,8 +945,9 @@ inserted:
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ce->e_reusable = 0;
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ea_bdebug(new_bh, "reusing; refcount now=%d",
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ref);
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ext4_xattr_block_csum_set(inode, new_bh);
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unlock_buffer(new_bh);
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error = ext4_handle_dirty_xattr_block(handle,
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error = ext4_handle_dirty_metadata(handle,
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inode,
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new_bh);
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if (error)
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@ -1003,11 +999,12 @@ getblk_failed:
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goto getblk_failed;
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}
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memcpy(new_bh->b_data, s->base, new_bh->b_size);
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ext4_xattr_block_csum_set(inode, new_bh);
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set_buffer_uptodate(new_bh);
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unlock_buffer(new_bh);
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ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
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error = ext4_handle_dirty_xattr_block(handle,
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inode, new_bh);
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error = ext4_handle_dirty_metadata(handle, inode,
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new_bh);
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if (error)
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goto cleanup;
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}
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