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replace do_setxattr() with saner helpers.
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io_uring setxattr logics duplicates stuff from fs/xattr.c; provide
saner helpers (filename_setxattr() and file_setxattr() resp.) and
use them.

NB: putname(ERR_PTR()) is a no-op

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro committed Nov 6, 2024
1 parent a10c4c5 commit 66d7ac6
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Showing 3 changed files with 54 additions and 62 deletions.
6 changes: 3 additions & 3 deletions fs/internal.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -285,10 +285,10 @@ ssize_t do_getxattr(struct mnt_idmap *idmap,
struct dentry *d,
struct kernel_xattr_ctx *ctx);

int file_setxattr(struct file *file, struct kernel_xattr_ctx *ctx);
int filename_setxattr(int dfd, struct filename *filename,
unsigned int lookup_flags, struct kernel_xattr_ctx *ctx);
int setxattr_copy(const char __user *name, struct kernel_xattr_ctx *ctx);
int do_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
struct kernel_xattr_ctx *ctx);

int import_xattr_name(struct xattr_name *kname, const char __user *name);

int may_write_xattr(struct mnt_idmap *idmap, struct inode *inode);
Expand Down
69 changes: 44 additions & 25 deletions fs/xattr.c
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Original file line number Diff line number Diff line change
Expand Up @@ -626,7 +626,7 @@ int setxattr_copy(const char __user *name, struct kernel_xattr_ctx *ctx)
return error;
}

int do_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
static int do_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
struct kernel_xattr_ctx *ctx)
{
if (is_posix_acl_xattr(ctx->kname->name))
Expand All @@ -637,32 +637,32 @@ int do_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
ctx->kvalue, ctx->size, ctx->flags);
}

static int path_setxattr(const char __user *pathname,
const char __user *name, const void __user *value,
size_t size, int flags, unsigned int lookup_flags)
int file_setxattr(struct file *f, struct kernel_xattr_ctx *ctx)
{
int error = mnt_want_write_file(f);

if (!error) {
audit_file(f);
error = do_setxattr(file_mnt_idmap(f), f->f_path.dentry, ctx);
mnt_drop_write_file(f);
}
return error;
}

/* unconditionally consumes filename */
int filename_setxattr(int dfd, struct filename *filename,
unsigned int lookup_flags, struct kernel_xattr_ctx *ctx)
{
struct xattr_name kname;
struct kernel_xattr_ctx ctx = {
.cvalue = value,
.kvalue = NULL,
.size = size,
.kname = &kname,
.flags = flags,
};
struct path path;
int error;

error = setxattr_copy(name, &ctx);
if (error)
return error;

retry:
error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
error = filename_lookup(dfd, filename, lookup_flags, &path, NULL);
if (error)
goto out;
error = mnt_want_write(path.mnt);
if (!error) {
error = do_setxattr(mnt_idmap(path.mnt), path.dentry, &ctx);
error = do_setxattr(mnt_idmap(path.mnt), path.dentry, ctx);
mnt_drop_write(path.mnt);
}
path_put(&path);
Expand All @@ -672,6 +672,30 @@ static int path_setxattr(const char __user *pathname,
}

out:
putname(filename);
return error;
}

static int path_setxattr(const char __user *pathname,
const char __user *name, const void __user *value,
size_t size, int flags, unsigned int lookup_flags)
{
struct xattr_name kname;
struct kernel_xattr_ctx ctx = {
.cvalue = value,
.kvalue = NULL,
.size = size,
.kname = &kname,
.flags = flags,
};
int error;

error = setxattr_copy(name, &ctx);
if (error)
return error;

error = filename_setxattr(AT_FDCWD, getname(pathname), lookup_flags,
&ctx);
kvfree(ctx.kvalue);
return error;
}
Expand Down Expand Up @@ -707,17 +731,12 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,

if (fd_empty(f))
return -EBADF;
audit_file(fd_file(f));

error = setxattr_copy(name, &ctx);
if (error)
return error;

error = mnt_want_write_file(fd_file(f));
if (!error) {
error = do_setxattr(file_mnt_idmap(fd_file(f)),
fd_file(f)->f_path.dentry, &ctx);
mnt_drop_write_file(fd_file(f));
}
error = file_setxattr(fd_file(f), &ctx);
kvfree(ctx.kvalue);
return error;
}
Expand Down
41 changes: 7 additions & 34 deletions io_uring/xattr.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -187,65 +187,38 @@ int io_setxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
path = u64_to_user_ptr(READ_ONCE(sqe->addr3));

ix->filename = getname(path);
if (IS_ERR(ix->filename)) {
ret = PTR_ERR(ix->filename);
ix->filename = NULL;
}
if (IS_ERR(ix->filename))
return PTR_ERR(ix->filename);

return ret;
return 0;
}

int io_fsetxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
return __io_setxattr_prep(req, sqe);
}

static int __io_setxattr(struct io_kiocb *req, unsigned int issue_flags,
const struct path *path)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
int ret;

ret = mnt_want_write(path->mnt);
if (!ret) {
ret = do_setxattr(mnt_idmap(path->mnt), path->dentry, &ix->ctx);
mnt_drop_write(path->mnt);
}

return ret;
}

int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
int ret;

WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

ret = __io_setxattr(req, issue_flags, &req->file->f_path);
ret = file_setxattr(req->file, &ix->ctx);
io_xattr_finish(req, ret);
return IOU_OK;
}

int io_setxattr(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
unsigned int lookup_flags = LOOKUP_FOLLOW;
struct path path;
int ret;

WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

retry:
ret = filename_lookup(AT_FDCWD, ix->filename, lookup_flags, &path, NULL);
if (!ret) {
ret = __io_setxattr(req, issue_flags, &path);
path_put(&path);
if (retry_estale(ret, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
}

ret = filename_setxattr(AT_FDCWD, ix->filename, LOOKUP_FOLLOW, &ix->ctx);
ix->filename = NULL;
io_xattr_finish(req, ret);
return IOU_OK;
}

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