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Message-ID: <20240822012523.141846-11-vinicius.gomes@intel.com>
Date: Wed, 21 Aug 2024 18:25:17 -0700
From: Vinicius Costa Gomes <vinicius.gomes@...el.com>
To: brauner@...nel.org,
amir73il@...il.com,
hu1.chen@...el.com
Cc: miklos@...redi.hu,
malini.bhandaru@...el.com,
tim.c.chen@...el.com,
mikko.ylinen@...el.com,
lizhen.you@...el.com,
linux-unionfs@...r.kernel.org,
linux-fsdevel@...r.kernel.org,
linux-kernel@...r.kernel.org,
Vinicius Costa Gomes <vinicius.gomes@...el.com>
Subject: [PATCH v2 10/16] overlayfs/file: Convert to cred_guard()
Replace the override_creds_light()/revert_creds_light() pairs of
operations with cred_guard()/cred_scoped_guard().
Only ovl_copyfile() and ovl_fallocate() 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@...el.com>
---
fs/overlayfs/file.c | 64 ++++++++++++++++++---------------------------
1 file changed, 25 insertions(+), 39 deletions(-)
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 5533fedcbc47..97aa657e6916 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -31,7 +31,6 @@ static struct file *ovl_open_realfile(const struct file *file,
struct inode *inode = file_inode(file);
struct mnt_idmap *real_idmap;
struct file *realfile;
- const struct cred *old_cred;
int flags = file->f_flags | OVL_OPEN_FLAGS;
int acc_mode = ACC_MODE(flags);
int err;
@@ -39,7 +38,7 @@ static struct file *ovl_open_realfile(const struct file *file,
if (flags & O_APPEND)
acc_mode |= MAY_APPEND;
- old_cred = ovl_override_creds_light(inode->i_sb);
+ cred_guard(ovl_creds(inode->i_sb));
real_idmap = mnt_idmap(realpath->mnt);
err = inode_permission(real_idmap, realinode, MAY_OPEN | acc_mode);
if (err) {
@@ -51,7 +50,6 @@ static struct file *ovl_open_realfile(const struct file *file,
realfile = backing_file_open(&file->f_path, flags, realpath,
current_cred());
}
- revert_creds_light(old_cred);
pr_debug("open(%p[%pD2/%c], 0%o) -> (%p, 0%o)\n",
file, file, ovl_whatisit(inode, realinode), file->f_flags,
@@ -182,7 +180,6 @@ static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)
{
struct inode *inode = file_inode(file);
struct fd real;
- const struct cred *old_cred;
loff_t ret;
/*
@@ -211,9 +208,8 @@ static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)
ovl_inode_lock(inode);
real.file->f_pos = file->f_pos;
- old_cred = ovl_override_creds_light(inode->i_sb);
+ cred_guard(ovl_creds(inode->i_sb));
ret = vfs_llseek(real.file, offset, whence);
- revert_creds_light(old_cred);
file->f_pos = real.file->f_pos;
ovl_inode_unlock(inode);
@@ -385,7 +381,6 @@ static ssize_t ovl_splice_write(struct pipe_inode_info *pipe, struct file *out,
static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
struct fd real;
- const struct cred *old_cred;
int ret;
ret = ovl_sync_status(OVL_FS(file_inode(file)->i_sb));
@@ -398,9 +393,8 @@ static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
/* Don't sync lower file for fear of receiving EROFS error */
if (file_inode(real.file) == ovl_inode_upper(file_inode(file))) {
- old_cred = ovl_override_creds_light(file_inode(file)->i_sb);
+ cred_guard(ovl_creds(file_inode(file)->i_sb));
ret = vfs_fsync_range(real.file, start, end, datasync);
- revert_creds_light(old_cred);
}
fdput(real);
@@ -424,7 +418,6 @@ static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len
{
struct inode *inode = file_inode(file);
struct fd real;
- const struct cred *old_cred;
int ret;
inode_lock(inode);
@@ -438,9 +431,8 @@ static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len
if (ret)
goto out_unlock;
- old_cred = ovl_override_creds_light(file_inode(file)->i_sb);
- ret = vfs_fallocate(real.file, mode, offset, len);
- revert_creds_light(old_cred);
+ cred_scoped_guard(ovl_creds(file_inode(file)->i_sb))
+ ret = vfs_fallocate(real.file, mode, offset, len);
/* Update size */
ovl_file_modified(file);
@@ -456,16 +448,14 @@ static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len
static int ovl_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
{
struct fd real;
- const struct cred *old_cred;
int ret;
ret = ovl_real_fdget(file, &real);
if (ret)
return ret;
- old_cred = ovl_override_creds_light(file_inode(file)->i_sb);
+ cred_guard(ovl_creds(file_inode(file)->i_sb));
ret = vfs_fadvise(real.file, offset, len, advice);
- revert_creds_light(old_cred);
fdput(real);
@@ -484,7 +474,6 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in,
{
struct inode *inode_out = file_inode(file_out);
struct fd real_in, real_out;
- const struct cred *old_cred;
loff_t ret;
inode_lock(inode_out);
@@ -506,26 +495,25 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in,
goto out_unlock;
}
- old_cred = ovl_override_creds_light(file_inode(file_out)->i_sb);
- switch (op) {
- case OVL_COPY:
- ret = vfs_copy_file_range(real_in.file, pos_in,
- real_out.file, pos_out, len, flags);
- break;
-
- case OVL_CLONE:
- ret = vfs_clone_file_range(real_in.file, pos_in,
- real_out.file, pos_out, len, flags);
- break;
-
- case OVL_DEDUPE:
- ret = vfs_dedupe_file_range_one(real_in.file, pos_in,
- real_out.file, pos_out, len,
- flags);
- break;
+ cred_scoped_guard(ovl_creds(file_inode(file_out)->i_sb)) {
+ switch (op) {
+ case OVL_COPY:
+ ret = vfs_copy_file_range(real_in.file, pos_in,
+ real_out.file, pos_out, len, flags);
+ break;
+
+ case OVL_CLONE:
+ ret = vfs_clone_file_range(real_in.file, pos_in,
+ real_out.file, pos_out, len, flags);
+ break;
+
+ case OVL_DEDUPE:
+ ret = vfs_dedupe_file_range_one(real_in.file, pos_in,
+ real_out.file, pos_out, len,
+ flags);
+ break;
+ }
}
- revert_creds_light(old_cred);
-
/* Update size */
ovl_file_modified(file_out);
@@ -576,7 +564,6 @@ static loff_t ovl_remap_file_range(struct file *file_in, loff_t pos_in,
static int ovl_flush(struct file *file, fl_owner_t id)
{
struct fd real;
- const struct cred *old_cred;
int err;
err = ovl_real_fdget(file, &real);
@@ -584,9 +571,8 @@ static int ovl_flush(struct file *file, fl_owner_t id)
return err;
if (real.file->f_op->flush) {
- old_cred = ovl_override_creds_light(file_inode(file)->i_sb);
+ cred_guard(ovl_creds(file_inode(file)->i_sb));
err = real.file->f_op->flush(real.file, id);
- revert_creds_light(old_cred);
}
fdput(real);
--
2.46.0
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