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authorLinus Torvalds <torvalds@linux-foundation.org>2019-03-12 14:48:52 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-12 14:48:52 -0700
commitf88c5942cfaf7d55e46d395136cccaca65b2e3bf (patch)
tree33640d03b5d3652c41bb09b49d85af2b3659b820
parentdfee9c257b102d7c0407629eef2ed32e152de0d2 (diff)
parent993a0b2aec52754f0897b1dab4c453be8217cae5 (diff)
downloadlinux-f88c5942cfaf7d55e46d395136cccaca65b2e3bf.tar.gz
Merge tag 'ovl-update-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs updates from Miklos Szeredi: "Fix copy up of security related xattrs" * tag 'ovl-update-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: Do not lose security.capability xattr over metadata file copy-up ovl: During copy up, first copy up data and then xattrs
-rw-r--r--fs/overlayfs/copy_up.c59
-rw-r--r--fs/overlayfs/overlayfs.h2
-rw-r--r--fs/overlayfs/util.c55
3 files changed, 81 insertions, 35 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 9e62dcf06fc4..68b3303e4b46 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -443,6 +443,24 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
{
int err;
+ /*
+ * Copy up data first and then xattrs. Writing data after
+ * xattrs will remove security.capability xattr automatically.
+ */
+ if (S_ISREG(c->stat.mode) && !c->metacopy) {
+ struct path upperpath, datapath;
+
+ ovl_path_upper(c->dentry, &upperpath);
+ if (WARN_ON(upperpath.dentry != NULL))
+ return -EIO;
+ upperpath.dentry = temp;
+
+ ovl_path_lowerdata(c->dentry, &datapath);
+ err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);
+ if (err)
+ return err;
+ }
+
err = ovl_copy_xattr(c->lowerpath.dentry, temp);
if (err)
return err;
@@ -460,19 +478,6 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
return err;
}
- if (S_ISREG(c->stat.mode) && !c->metacopy) {
- struct path upperpath, datapath;
-
- ovl_path_upper(c->dentry, &upperpath);
- BUG_ON(upperpath.dentry != NULL);
- upperpath.dentry = temp;
-
- ovl_path_lowerdata(c->dentry, &datapath);
- err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);
- if (err)
- return err;
- }
-
if (c->metacopy) {
err = ovl_check_setxattr(c->dentry, temp, OVL_XATTR_METACOPY,
NULL, 0, -EOPNOTSUPP);
@@ -737,6 +742,8 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
{
struct path upperpath, datapath;
int err;
+ char *capability = NULL;
+ ssize_t uninitialized_var(cap_size);
ovl_path_upper(c->dentry, &upperpath);
if (WARN_ON(upperpath.dentry == NULL))
@@ -746,15 +753,37 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
if (WARN_ON(datapath.dentry == NULL))
return -EIO;
+ if (c->stat.size) {
+ err = cap_size = ovl_getxattr(upperpath.dentry, XATTR_NAME_CAPS,
+ &capability, 0);
+ if (err < 0 && err != -ENODATA)
+ goto out;
+ }
+
err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);
if (err)
- return err;
+ goto out_free;
+
+ /*
+ * Writing to upper file will clear security.capability xattr. We
+ * don't want that to happen for normal copy-up operation.
+ */
+ if (capability) {
+ err = ovl_do_setxattr(upperpath.dentry, XATTR_NAME_CAPS,
+ capability, cap_size, 0);
+ if (err)
+ goto out_free;
+ }
+
err = vfs_removexattr(upperpath.dentry, OVL_XATTR_METACOPY);
if (err)
- return err;
+ goto out_free;
ovl_set_upperdata(d_inode(c->dentry));
+out_free:
+ kfree(capability);
+out:
return err;
}
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 5e45cb3630a0..9c6018287d57 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -277,6 +277,8 @@ int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
int ovl_check_metacopy_xattr(struct dentry *dentry);
bool ovl_is_metacopy_dentry(struct dentry *dentry);
char *ovl_get_redirect_xattr(struct dentry *dentry, int padding);
+ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
+ size_t padding);
static inline bool ovl_is_impuredir(struct dentry *dentry)
{
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 7c01327b1852..4035e640f402 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -863,28 +863,49 @@ bool ovl_is_metacopy_dentry(struct dentry *dentry)
return (oe->numlower > 1);
}
-char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
+ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
+ size_t padding)
{
- int res;
- char *s, *next, *buf = NULL;
+ ssize_t res;
+ char *buf = NULL;
- res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, NULL, 0);
+ res = vfs_getxattr(dentry, name, NULL, 0);
if (res < 0) {
if (res == -ENODATA || res == -EOPNOTSUPP)
- return NULL;
+ return -ENODATA;
goto fail;
}
- buf = kzalloc(res + padding + 1, GFP_KERNEL);
- if (!buf)
- return ERR_PTR(-ENOMEM);
+ if (res != 0) {
+ buf = kzalloc(res + padding, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
- if (res == 0)
- goto invalid;
+ res = vfs_getxattr(dentry, name, buf, res);
+ if (res < 0)
+ goto fail;
+ }
+ *value = buf;
+
+ return res;
+
+fail:
+ pr_warn_ratelimited("overlayfs: failed to get xattr %s: err=%zi)\n",
+ name, res);
+ kfree(buf);
+ return res;
+}
- res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, buf, res);
+char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
+{
+ int res;
+ char *s, *next, *buf = NULL;
+
+ res = ovl_getxattr(dentry, OVL_XATTR_REDIRECT, &buf, padding + 1);
+ if (res == -ENODATA)
+ return NULL;
if (res < 0)
- goto fail;
+ return ERR_PTR(res);
if (res == 0)
goto invalid;
@@ -900,15 +921,9 @@ char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
}
return buf;
-
-err_free:
- kfree(buf);
- return ERR_PTR(res);
-fail:
- pr_warn_ratelimited("overlayfs: failed to get redirect (%i)\n", res);
- goto err_free;
invalid:
pr_warn_ratelimited("overlayfs: invalid redirect (%s)\n", buf);
res = -EINVAL;
- goto err_free;
+ kfree(buf);
+ return ERR_PTR(res);
}