On May 13, 2019, at 4:40 PM, Chengguang Xu <cgxu519@xxxxxxxxxxx> wrote:
>
> Introduce helper function ext2_xattr_header_valid()
> for xattr header validation and clean up the header
> check ralated code.
>
> Signed-off-by: Chengguang Xu <cgxu519@xxxxxxxxxxx>
Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx>
> ---
> v1->v2:
> - Pass xattr header to ext2_xattr_header_valid().
> - Change signed-off mail address.
>
> fs/ext2/xattr.c | 31 ++++++++++++++++++++-----------
> 1 file changed, 20 insertions(+), 11 deletions(-)
>
> diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
> index 1e33e0ac8cf1..db27260d6a5b 100644
> --- a/fs/ext2/xattr.c
> +++ b/fs/ext2/xattr.c
> @@ -134,6 +134,16 @@ ext2_xattr_handler(int name_index)
> return handler;
> }
>
> +static bool
> +ext2_xattr_header_valid(struct ext2_xattr_header *header)
> +{
> + if (header->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
> + header->h_blocks != cpu_to_le32(1))
> + return false;
> +
> + return true;
> +}
> +
> /*
> * ext2_xattr_get()
> *
> @@ -176,9 +186,9 @@ ext2_xattr_get(struct inode *inode, int name_index, const char *name,
> ea_bdebug(bh, "b_count=%d, refcount=%d",
> atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount));
> end = bh->b_data + bh->b_size;
> - if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
> - HDR(bh)->h_blocks != cpu_to_le32(1)) {
> -bad_block: ext2_error(inode->i_sb, "ext2_xattr_get",
> + if (!ext2_xattr_header_valid(HDR(bh))) {
> +bad_block:
> + ext2_error(inode->i_sb, "ext2_xattr_get",
> "inode %ld: bad block %d", inode->i_ino,
> EXT2_I(inode)->i_file_acl);
> error = -EIO;
> @@ -266,9 +276,9 @@ ext2_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
> ea_bdebug(bh, "b_count=%d, refcount=%d",
> atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount));
> end = bh->b_data + bh->b_size;
> - if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
> - HDR(bh)->h_blocks != cpu_to_le32(1)) {
> -bad_block: ext2_error(inode->i_sb, "ext2_xattr_list",
> + if (!ext2_xattr_header_valid(HDR(bh))) {
> +bad_block:
> + ext2_error(inode->i_sb, "ext2_xattr_list",
> "inode %ld: bad block %d", inode->i_ino,
> EXT2_I(inode)->i_file_acl);
> error = -EIO;
> @@ -406,9 +416,9 @@ ext2_xattr_set(struct inode *inode, int name_index, const char *name,
> le32_to_cpu(HDR(bh)->h_refcount));
> header = HDR(bh);
> end = bh->b_data + bh->b_size;
> - if (header->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
> - header->h_blocks != cpu_to_le32(1)) {
> -bad_block: ext2_error(sb, "ext2_xattr_set",
> + if (!ext2_xattr_header_valid(header)) {
> +bad_block:
> + ext2_error(sb, "ext2_xattr_set",
> "inode %ld: bad block %d", inode->i_ino,
> EXT2_I(inode)->i_file_acl);
> error = -EIO;
> @@ -784,8 +794,7 @@ ext2_xattr_delete_inode(struct inode *inode)
> goto cleanup;
> }
> ea_bdebug(bh, "b_count=%d", atomic_read(&(bh->b_count)));
> - if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
> - HDR(bh)->h_blocks != cpu_to_le32(1)) {
> + if (!ext2_xattr_header_valid(HDR(bh))) {
> ext2_error(inode->i_sb, "ext2_xattr_delete_inode",
> "inode %ld: bad block %d", inode->i_ino,
> EXT2_I(inode)->i_file_acl);
> --
> 2.17.2
>
>
Cheers, Andreas
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