From: Tao Ma <boyu.mt@taobao.com>
Date: Mon, 17 Oct 2011 14:13:46 +0000 (-0400)
Subject: ext4: avoid stamping on other memories in ext4_ext_insert_index()
X-Git-Tag: MMI-PSA29.97-13-9~18150^2~49
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=f472e02669073e4f1a388142bafa0f806fae841c;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git

ext4: avoid stamping on other memories in ext4_ext_insert_index()

Add a sanity check to make sure ix hasn't gone beyond the valid bounds
of the extent block.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index f473ddf0bd94..5c4861210d4c 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -779,6 +779,11 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 		ix = curp->p_idx;
 	}
 
+	if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
+		EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
+		return -EIO;
+	}
+
 	ix->ei_block = cpu_to_le32(logical);
 	ext4_idx_store_pblock(ix, ptr);
 	le16_add_cpu(&curp->p_hdr->eh_entries, 1);