| Submitter | Robin Dong |
|---|---|
| Date | June 27, 2011, 6:29 a.m. |
| Message ID | <1309156180-3899-1-git-send-email-sanbai@taobao.com> |
| Download | mbox | patch |
| Permalink | /patch/102109/ |
| State | Accepted |
| Headers | show |
Comments
On Mon, Jun 27, 2011 at 02:29:40PM +0800, Robin Dong wrote: > If eh_entries is equal to (or greater than) eh_max, the operation of > inserting new extent_idx will make number of entries overflow. > So check eh_entries before inserting the new extent_idx. > > Although there is no bug case according the code (function ext4_ext_insert_index > is called by ext4_ext_split and ext4_ext_split is called only if the index > block has free space), the right logic should be "lookup the capacity before > insertion". > > Signed-off-by: Robin Dong <sanbai@taobao.com> Thanks, added to the ext4 tree. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Patch
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index eb63c7b..792e77e 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -776,6 +776,16 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode, logical, le32_to_cpu(curp->p_idx->ei_block)); return -EIO; } + + if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries) + >= le16_to_cpu(curp->p_hdr->eh_max))) { + EXT4_ERROR_INODE(inode, + "eh_entries %d >= eh_max %d!", + le16_to_cpu(curp->p_hdr->eh_entries), + le16_to_cpu(curp->p_hdr->eh_max)); + return -EIO; + } + len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx; if (logical > le32_to_cpu(curp->p_idx->ei_block)) { /* insert after */ @@ -805,14 +815,6 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode, ext4_idx_store_pblock(ix, ptr); le16_add_cpu(&curp->p_hdr->eh_entries, 1); - if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries) - > le16_to_cpu(curp->p_hdr->eh_max))) { - EXT4_ERROR_INODE(inode, - "eh_entries %d > eh_max %d!", - le16_to_cpu(curp->p_hdr->eh_entries), - le16_to_cpu(curp->p_hdr->eh_max)); - return -EIO; - } if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) { EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!"); return -EIO;
If eh_entries is equal to (or greater than) eh_max, the operation of inserting new extent_idx will make number of entries overflow. So check eh_entries before inserting the new extent_idx. Although there is no bug case according the code (function ext4_ext_insert_index is called by ext4_ext_split and ext4_ext_split is called only if the index block has free space), the right logic should be "lookup the capacity before insertion". Signed-off-by: Robin Dong <sanbai@taobao.com> --- fs/ext4/extents.c | 18 ++++++++++-------- 1 files changed, 10 insertions(+), 8 deletions(-)