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Commit a17d5232 authored by Duane Griffin's avatar Duane Griffin Committed by Al Viro
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eCryptfs: check readlink result was not an error before using it 



The result from readlink is being used to index into the link name
buffer without checking whether it is a valid length. If readlink
returns an error this will fault or cause memory corruption.

Cc: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Cc: Dustin Kirkland <kirkland@canonical.com>
Cc: ecryptfs-devel@lists.launchpad.net
Signed-off-by: default avatarDuane Griffin <duaneg@dghda.com>
Acked-by: default avatarMichael Halcrow <mhalcrow@us.ibm.com>
Acked-by: default avatarTyler Hicks <tyhicks@linux.vnet.ibm.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 5cc4a034

fs/ecryptfs/inode.c

+2 −1
Original line number Diff line number Diff line
@@ -673,10 +673,11 @@ static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd) 
	ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "

			"dentry->d_name.name = [%s]\n", dentry->d_name.name);

	rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);

	buf[rc] = '\0';

	set_fs(old_fs);

	if (rc < 0)

		goto out_free;

	else

		buf[rc] = '\0';

	rc = 0;

	nd_set_link(nd, buf);

	goto out;