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-rw-r--r--fs/overlayfs/export.c80
1 files changed, 49 insertions, 31 deletions
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index 73c9775215b3..70e55588aedc 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -211,10 +211,11 @@ static int ovl_check_encode_origin(struct dentry *dentry)
return 1;
}
-static int ovl_d_to_fh(struct dentry *dentry, char *buf, int buflen)
+static int ovl_dentry_to_fid(struct dentry *dentry, u32 *fid, int buflen)
{
struct ovl_fh *fh = NULL;
int err, enc_lower;
+ int len;
/*
* Check if we should encode a lower or upper file handle and maybe
@@ -231,11 +232,12 @@ static int ovl_d_to_fh(struct dentry *dentry, char *buf, int buflen)
return PTR_ERR(fh);
err = -EOVERFLOW;
- if (fh->len > buflen)
+ len = OVL_FH_LEN(fh);
+ if (len > buflen)
goto fail;
- memcpy(buf, (char *)fh, fh->len);
- err = fh->len;
+ memcpy(fid, fh, len);
+ err = len;
out:
kfree(fh);
@@ -243,31 +245,16 @@ out:
fail:
pr_warn_ratelimited("overlayfs: failed to encode file handle (%pd2, err=%i, buflen=%d, len=%d, type=%d)\n",
- dentry, err, buflen, fh ? (int)fh->len : 0,
- fh ? fh->type : 0);
+ dentry, err, buflen, fh ? (int)fh->fb.len : 0,
+ fh ? fh->fb.type : 0);
goto out;
}
-static int ovl_dentry_to_fh(struct dentry *dentry, u32 *fid, int *max_len)
-{
- int res, len = *max_len << 2;
-
- res = ovl_d_to_fh(dentry, (char *)fid, len);
- if (res <= 0)
- return FILEID_INVALID;
-
- len = res;
-
- /* Round up to dwords */
- *max_len = (len + 3) >> 2;
- return OVL_FILEID;
-}
-
static int ovl_encode_fh(struct inode *inode, u32 *fid, int *max_len,
struct inode *parent)
{
struct dentry *dentry;
- int type;
+ int bytes = *max_len << 2;
/* TODO: encode connectable file handles */
if (parent)
@@ -277,10 +264,14 @@ static int ovl_encode_fh(struct inode *inode, u32 *fid, int *max_len,
if (WARN_ON(!dentry))
return FILEID_INVALID;
- type = ovl_dentry_to_fh(dentry, fid, max_len);
-
+ bytes = ovl_dentry_to_fid(dentry, fid, bytes);
dput(dentry);
- return type;
+ if (bytes <= 0)
+ return FILEID_INVALID;
+
+ *max_len = bytes >> 2;
+
+ return OVL_FILEID_V1;
}
/*
@@ -777,24 +768,45 @@ out_err:
goto out;
}
+static struct ovl_fh *ovl_fid_to_fh(struct fid *fid, int buflen, int fh_type)
+{
+ struct ovl_fh *fh;
+
+ /* If on-wire inner fid is aligned - nothing to do */
+ if (fh_type == OVL_FILEID_V1)
+ return (struct ovl_fh *)fid;
+
+ if (fh_type != OVL_FILEID_V0)
+ return ERR_PTR(-EINVAL);
+
+ fh = kzalloc(buflen, GFP_KERNEL);
+ if (!fh)
+ return ERR_PTR(-ENOMEM);
+
+ /* Copy unaligned inner fh into aligned buffer */
+ memcpy(&fh->fb, fid, buflen - OVL_FH_WIRE_OFFSET);
+ return fh;
+}
+
static struct dentry *ovl_fh_to_dentry(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type)
{
struct dentry *dentry = NULL;
- struct ovl_fh *fh = (struct ovl_fh *) fid;
+ struct ovl_fh *fh = NULL;
int len = fh_len << 2;
unsigned int flags = 0;
int err;
- err = -EINVAL;
- if (fh_type != OVL_FILEID)
+ fh = ovl_fid_to_fh(fid, len, fh_type);
+ err = PTR_ERR(fh);
+ if (IS_ERR(fh))
goto out_err;
err = ovl_check_fh_len(fh, len);
if (err)
goto out_err;
- flags = fh->flags;
+ flags = fh->fb.flags;
dentry = (flags & OVL_FH_FLAG_PATH_UPPER) ?
ovl_upper_fh_to_d(sb, fh) :
ovl_lower_fh_to_d(sb, fh);
@@ -802,12 +814,18 @@ static struct dentry *ovl_fh_to_dentry(struct super_block *sb, struct fid *fid,
if (IS_ERR(dentry) && err != -ESTALE)
goto out_err;
+out:
+ /* We may have needed to re-align OVL_FILEID_V0 */
+ if (!IS_ERR_OR_NULL(fh) && fh != (void *)fid)
+ kfree(fh);
+
return dentry;
out_err:
pr_warn_ratelimited("overlayfs: failed to decode file handle (len=%d, type=%d, flags=%x, err=%i)\n",
- len, fh_type, flags, err);
- return ERR_PTR(err);
+ fh_len, fh_type, flags, err);
+ dentry = ERR_PTR(err);
+ goto out;
}
static struct dentry *ovl_fh_to_parent(struct super_block *sb, struct fid *fid,