Replace the override_creds_light()/revert_creds_light() pairs of
operations with cred_guard()/cred_scoped_guard().
Only ovl_maybe_lookup_lowerdata() use cred_scoped_guard(), because of
'goto', which can cause the cleanup flow to run on garbage memory.
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx>
---
fs/overlayfs/namei.c | 20 +++++---------------
1 file changed, 5 insertions(+), 15 deletions(-)
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index e52d6ae8eeb5..723731bc3678 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -953,15 +953,12 @@ static int ovl_maybe_validate_verity(struct dentry *dentry)
return err;
if (!ovl_test_flag(OVL_VERIFIED_DIGEST, inode)) {
- const struct cred *old_cred;
-
- old_cred = ovl_override_creds_light(dentry->d_sb);
+ cred_guard(ovl_creds(dentry->d_sb));
err = ovl_validate_verity(ofs, &metapath, &datapath);
if (err == 0)
ovl_set_flag(OVL_VERIFIED_DIGEST, inode);
- revert_creds_light(old_cred);
}
ovl_inode_unlock(inode);
@@ -975,7 +972,6 @@ static int ovl_maybe_lookup_lowerdata(struct dentry *dentry)
struct inode *inode = d_inode(dentry);
const char *redirect = ovl_lowerdata_redirect(inode);
struct ovl_path datapath = {};
- const struct cred *old_cred;
int err;
if (!redirect || ovl_dentry_lowerdata(dentry))
@@ -993,9 +989,8 @@ static int ovl_maybe_lookup_lowerdata(struct dentry *dentry)
if (ovl_dentry_lowerdata(dentry))
goto out;
- old_cred = ovl_override_creds_light(dentry->d_sb);
- err = ovl_lookup_data_layers(dentry, redirect, &datapath);
- revert_creds_light(old_cred);
+ cred_scoped_guard(ovl_creds(dentry->d_sb))
+ err = ovl_lookup_data_layers(dentry, redirect, &datapath);
if (err)
goto out_err;
@@ -1030,7 +1025,6 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
struct ovl_entry *oe = NULL;
- const struct cred *old_cred;
struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
struct ovl_entry *poe = OVL_E(dentry->d_parent);
struct ovl_entry *roe = OVL_E(dentry->d_sb->s_root);
@@ -1061,7 +1055,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
if (dentry->d_name.len > ofs->namelen)
return ERR_PTR(-ENAMETOOLONG);
- old_cred = ovl_override_creds_light(dentry->d_sb);
+ cred_guard(ovl_creds(dentry->d_sb));
upperdir = ovl_dentry_upper(dentry->d_parent);
if (upperdir) {
d.layer = &ofs->layers[0];
@@ -1342,7 +1336,6 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
ovl_dentry_init_reval(dentry, upperdentry, OVL_I_E(inode));
- revert_creds_light(old_cred);
if (origin_path) {
dput(origin_path->dentry);
kfree(origin_path);
@@ -1366,7 +1359,6 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
kfree(upperredirect);
out:
kfree(d.redirect);
- revert_creds_light(old_cred);
return ERR_PTR(err);
}
@@ -1374,7 +1366,6 @@ bool ovl_lower_positive(struct dentry *dentry)
{
struct ovl_entry *poe = OVL_E(dentry->d_parent);
const struct qstr *name = &dentry->d_name;
- const struct cred *old_cred;
unsigned int i;
bool positive = false;
bool done = false;
@@ -1390,7 +1381,7 @@ bool ovl_lower_positive(struct dentry *dentry)
if (!ovl_dentry_upper(dentry))
return true;
- old_cred = ovl_override_creds_light(dentry->d_sb);
+ cred_guard(ovl_creds(dentry->d_sb));
/* Positive upper -> have to look up lower to see whether it exists */
for (i = 0; !done && !positive && i < ovl_numlower(poe); i++) {
struct dentry *this;
@@ -1423,7 +1414,6 @@ bool ovl_lower_positive(struct dentry *dentry)
dput(this);
}
}
- revert_creds_light(old_cred);
return positive;
}
--
2.46.0
