From b22e8fedc19588864a6ba0acefbbed06f05ba713 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 29 Nov 2013 22:51:47 -0500 Subject: [PATCH] ecryptfs: fix failure handling in ->readlink() If ecryptfs_readlink_lower() fails, buf remains an uninitialized pointer and passing it nd_set_link() won't do anything good. Fixed by switching ecryptfs_readlink_lower() to saner API - make it return buf or ERR_PTR(...) and update callers. Signed-off-by: Al Viro --- fs/ecryptfs/inode.c | 29 +++++++++++++---------------- 1 file changed, 13 insertions(+), 16 deletions(-) diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c index c36c448..b167ca4 100644 --- a/fs/ecryptfs/inode.c +++ b/fs/ecryptfs/inode.c @@ -659,19 +659,17 @@ out_lock: return rc; } -static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf, - size_t *bufsiz) +static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz) { struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); char *lower_buf; + char *buf; mm_segment_t old_fs; int rc; lower_buf = kmalloc(PATH_MAX, GFP_KERNEL); - if (!lower_buf) { - rc = -ENOMEM; - goto out; - } + if (!lower_buf) + return ERR_PTR(-ENOMEM); old_fs = get_fs(); set_fs(get_ds()); rc = lower_dentry->d_inode->i_op->readlink(lower_dentry, @@ -680,21 +678,18 @@ static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf, set_fs(old_fs); if (rc < 0) goto out; - rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry->d_sb, + rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb, lower_buf, rc); out: kfree(lower_buf); - return rc; + return rc ? ERR_PTR(rc) : buf; } static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd) { - char *buf; - size_t len = PATH_MAX; - int rc; - - rc = ecryptfs_readlink_lower(dentry, &buf, &len); - if (rc) + size_t len; + char *buf = ecryptfs_readlink_lower(dentry, &len); + if (IS_ERR(buf)) goto out; fsstack_copy_attr_atime(dentry->d_inode, ecryptfs_dentry_to_lower(dentry)->d_inode); @@ -1003,10 +998,12 @@ static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry, char *target; size_t targetsiz; - rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz); - if (!rc) { + target = ecryptfs_readlink_lower(dentry, &targetsiz); + if (!IS_ERR(target)) { kfree(target); stat->size = targetsiz; + } else { + rc = PTR_ERR(target); } } return rc; -- 2.7.4