Attachment 3934 Details for Bug 5861 – Fix for DFS oops

Fix for DFS oops

0001--CIFS-Prevent-OOPs-when-mounting-with-remote-prefix(4).patch (text/x-diff), 4.22 KB, created by Steve French on 2009-02-10 13:19:46 UTC

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Creator: Steve French

Created: 2009-02-10 13:19:46 UTC

Size: 4.22 KB

patch

obsolete

>From 9b8119cb1ed2bed648e0b3b0d5c856813a52781b Mon Sep 17 00:00:00 2001
>From: Igor Mammedov <niallain@gmail.com>
>Date: Tue, 10 Feb 2009 14:10:26 +0300
>Subject: [PATCH] [CIFS] Prevent OOPs when mounting with remote prefixpath.
>    Fixes OOPs with message 'kernel BUG at fs/cifs/cifs_dfs_ref.c:274!'.
>    Checks if the prefixpath in an accesible while we are still in cifs_mount
>    and fails with reporting a error if we can't access the prefixpath
>
>Signed-off-by: Igor Mammedov <niallain@gmail.com>
>---
> fs/cifs/cifsproto.h |    1 +
> fs/cifs/connect.c   |   45 +++++++++++++++++++++++++++++++++++++++++++++
> fs/cifs/inode.c     |    4 ++--
> 3 files changed, 48 insertions(+), 2 deletions(-)
>
>diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
>index 382ba62..ec9f9c1 100644
>--- a/fs/cifs/cifsproto.h
>+++ b/fs/cifs/cifsproto.h
>@@ -42,6 +42,7 @@ extern void _FreeXid(unsigned int);
> #define GetXid() (int)_GetXid(); cFYI(1,("CIFS VFS: in %s as Xid: %d with uid: %d",__func__, xid,current_fsuid()));
> #define FreeXid(curr_xid) {_FreeXid(curr_xid); cFYI(1,("CIFS VFS: leaving %s (xid = %d) rc = %d",__func__,curr_xid,(int)rc));}
> extern char *build_path_from_dentry(struct dentry *);
>+extern char *cifs_build_path_to_root(struct cifs_sb_info *cifs_sb);
> extern char *build_wildcard_path_from_dentry(struct dentry *direntry);
> /* extern void renew_parental_timestamps(struct dentry *direntry);*/
> extern int SendReceive(const unsigned int /* xid */ , struct cifsSesInfo *,
>diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
>index 005df85..da0f4ff 100644
>--- a/fs/cifs/connect.c
>+++ b/fs/cifs/connect.c
>@@ -2180,6 +2180,33 @@ static void setup_cifs_sb(struct smb_vol *pvolume_info,
> 			   "mount option supported"));
> }
> 
>+static int
>+is_path_accessible(int xid, struct cifsTconInfo *tcon,
>+		   struct cifs_sb_info *cifs_sb, const char *full_path)
>+{
>+	int rc;
>+	__u64 inode_num;
>+	FILE_ALL_INFO *pfile_info;
>+
>+	rc = CIFSGetSrvInodeNumber(xid, tcon, full_path, &inode_num,
>+				   cifs_sb->local_nls,
>+				   cifs_sb->mnt_cifs_flags &
>+						CIFS_MOUNT_MAP_SPECIAL_CHR);
>+	if (rc != -EOPNOTSUPP)
>+		return rc;
>+
>+	pfile_info = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
>+	if (pfile_info == NULL)
>+		return -ENOMEM;
>+
>+	rc = CIFSSMBQPathInfo(xid, tcon, full_path, pfile_info,
>+			      0 /* not legacy */, cifs_sb->local_nls,
>+			      cifs_sb->mnt_cifs_flags &
>+				CIFS_MOUNT_MAP_SPECIAL_CHR);
>+	kfree(pfile_info);
>+	return rc;
>+}
>+
> int
> cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
> 	   char *mount_data, const char *devname)
>@@ -2190,6 +2217,7 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
> 	struct cifsSesInfo *pSesInfo = NULL;
> 	struct cifsTconInfo *tcon = NULL;
> 	struct TCP_Server_Info *srvTcp = NULL;
>+	char   *full_path;
> 
> 	xid = GetXid();
> 
>@@ -2426,6 +2454,23 @@ mount_fail_check:
> 		cifs_sb->rsize = min(cifs_sb->rsize,
> 			       (tcon->ses->server->maxBuf - MAX_CIFS_HDR_SIZE));
> 
>+	if (!rc && cifs_sb->prepathlen) {
>+		/* build_path_to_root works only when we have a valid tcon */
>+		full_path = cifs_build_path_to_root(cifs_sb);
>+		if (full_path == NULL) {
>+			rc = -ENOMEM;
>+			goto mount_fail_check;
>+		}
>+		rc = is_path_accessible(xid, tcon, cifs_sb, full_path);
>+		if (rc) {
>+			cERROR(1, ("Path %s in not accessible: %d",
>+						full_path, rc));
>+			kfree(full_path);
>+			goto mount_fail_check;
>+		}
>+		kfree(full_path);
>+	}
>+
> 	/* volume_info->password is freed above when existing session found
> 	(in which case it is not needed anymore) but when new sesion is created
> 	the password ptr is put in the new session structure (in which case the
>diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
>index bcf7b51..7342bfb 100644
>--- a/fs/cifs/inode.c
>+++ b/fs/cifs/inode.c
>@@ -621,7 +621,7 @@ static const struct inode_operations cifs_ipc_inode_ops = {
> 	.lookup = cifs_lookup,
> };
> 
>-static char *build_path_to_root(struct cifs_sb_info *cifs_sb)
>+char *cifs_build_path_to_root(struct cifs_sb_info *cifs_sb)
> {
> 	int pplen = cifs_sb->prepathlen;
> 	int dfsplen;
>@@ -678,7 +678,7 @@ struct inode *cifs_iget(struct super_block *sb, unsigned long ino)
> 		return inode;
> 
> 	cifs_sb = CIFS_SB(inode->i_sb);
>-	full_path = build_path_to_root(cifs_sb);
>+	full_path = cifs_build_path_to_root(cifs_sb);
> 	if (full_path == NULL)
> 		return ERR_PTR(-ENOMEM);
> 
>-- 
>1.6.0.2
>

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