Q: cifs, freeing volume_info->UNCip

From: J. R. Okajima
Date: Mon Aug 15 2011 - 19:22:26 EST



Hello,

CIFS cleanup_volume_info_contents() looks like having a memory
corruption problem.
When UNCip is set to "&vol->UNC[2]" in cifs_parse_mount_options(), it
should not be kfree()-ed in cleanup_volume_info_contents().

If it is correct and the code in mainline is not fixed yet, then here is
a patch.

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index ccc1afa..e0ea721 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2838,7 +2838,8 @@ cleanup_volume_info_contents(struct smb_vol *volume_info)
kfree(volume_info->username);
kzfree(volume_info->password);
kfree(volume_info->UNC);
- kfree(volume_info->UNCip);
+ if (volume_info->UNCip != volume_info->UNC + 2)
+ kfree(volume_info->UNCip);
kfree(volume_info->domainname);
kfree(volume_info->iocharset);
kfree(volume_info->prepath);


J. R. Okajima
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