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replace do_getxattr() with saner helpers.

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similar to do_setxattr() in the previous commit...

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2024-09-26 17:07:15 -04:00
parent 66d7ac6bdb
commit 0158005aaa
3 changed files with 62 additions and 67 deletions
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8
fs/internal.h
View File

@ -280,11 +280,9 @@ struct kernel_xattr_ctx {
unsigned int flags; unsigned int flags;
}; };
ssize_t file_getxattr(struct file *file, struct kernel_xattr_ctx *ctx);
ssize_t do_getxattr(struct mnt_idmap *idmap, ssize_t filename_getxattr(int dfd, struct filename *filename,
struct dentry *d, unsigned int lookup_flags, struct kernel_xattr_ctx *ctx);
struct kernel_xattr_ctx *ctx);
int file_setxattr(struct file *file, struct kernel_xattr_ctx *ctx); int file_setxattr(struct file *file, struct kernel_xattr_ctx *ctx);
int filename_setxattr(int dfd, struct filename *filename, int filename_setxattr(int dfd, struct filename *filename,
unsigned int lookup_flags, struct kernel_xattr_ctx *ctx); unsigned int lookup_flags, struct kernel_xattr_ctx *ctx);

90
fs/xattr.c
View File

@ -744,27 +744,28 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
/* /*
* Extended attribute GET operations * Extended attribute GET operations
*/ */
ssize_t static ssize_t
do_getxattr(struct mnt_idmap *idmap, struct dentry *d, do_getxattr(struct mnt_idmap *idmap, struct dentry *d,
struct kernel_xattr_ctx *ctx) struct kernel_xattr_ctx *ctx)
{ {
ssize_t error; ssize_t error;
char *kname = ctx->kname->name; char *kname = ctx->kname->name;
void *kvalue = NULL;
if (ctx->size) { if (ctx->size) {
if (ctx->size > XATTR_SIZE_MAX) if (ctx->size > XATTR_SIZE_MAX)
ctx->size = XATTR_SIZE_MAX; ctx->size = XATTR_SIZE_MAX;
ctx->kvalue = kvzalloc(ctx->size, GFP_KERNEL); kvalue = kvzalloc(ctx->size, GFP_KERNEL);
if (!ctx->kvalue) if (!kvalue)
return -ENOMEM; return -ENOMEM;
} }
if (is_posix_acl_xattr(ctx->kname->name)) if (is_posix_acl_xattr(kname))
error = do_get_acl(idmap, d, kname, ctx->kvalue, ctx->size); error = do_get_acl(idmap, d, kname, kvalue, ctx->size);
else else
error = vfs_getxattr(idmap, d, kname, ctx->kvalue, ctx->size); error = vfs_getxattr(idmap, d, kname, kvalue, ctx->size);
if (error > 0) { if (error > 0) {
if (ctx->size && copy_to_user(ctx->value, ctx->kvalue, error)) if (ctx->size && copy_to_user(ctx->value, kvalue, error))
error = -EFAULT; error = -EFAULT;
} else if (error == -ERANGE && ctx->size >= XATTR_SIZE_MAX) { } else if (error == -ERANGE && ctx->size >= XATTR_SIZE_MAX) {
/* The file system tried to returned a value bigger /* The file system tried to returned a value bigger
@ -772,18 +773,45 @@ do_getxattr(struct mnt_idmap *idmap, struct dentry *d,
error = -E2BIG; error = -E2BIG;
} }
kvfree(kvalue);
return error; return error;
} }
static ssize_t ssize_t file_getxattr(struct file *f, struct kernel_xattr_ctx *ctx)
getxattr(struct mnt_idmap *idmap, struct dentry *d, {
const char __user *name, void __user *value, size_t size) audit_file(f);
return do_getxattr(file_mnt_idmap(f), f->f_path.dentry, ctx);
}
/* unconditionally consumes filename */
ssize_t filename_getxattr(int dfd, struct filename *filename,
unsigned int lookup_flags, struct kernel_xattr_ctx *ctx)
{
struct path path;
ssize_t error;
retry:
error = filename_lookup(dfd, filename, lookup_flags, &path, NULL);
if (error)
goto out;
error = do_getxattr(mnt_idmap(path.mnt), path.dentry, ctx);
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
out:
putname(filename);
return error;
}
static ssize_t path_getxattr(const char __user *pathname,
const char __user *name, void __user *value,
size_t size, unsigned int lookup_flags)
{ {
ssize_t error; ssize_t error;
struct xattr_name kname; struct xattr_name kname;
struct kernel_xattr_ctx ctx = { struct kernel_xattr_ctx ctx = {
.value = value, .value = value,
.kvalue = NULL,
.size = size, .size = size,
.kname = &kname, .kname = &kname,
.flags = 0, .flags = 0,
@ -792,30 +820,7 @@ getxattr(struct mnt_idmap *idmap, struct dentry *d,
error = import_xattr_name(&kname, name); error = import_xattr_name(&kname, name);
if (error) if (error)
return error; return error;
return filename_getxattr(AT_FDCWD, getname(pathname), lookup_flags, &ctx);
error = do_getxattr(idmap, d, &ctx);
kvfree(ctx.kvalue);
return error;
}
static ssize_t path_getxattr(const char __user *pathname,
const char __user *name, void __user *value,
size_t size, unsigned int lookup_flags)
{
struct path path;
ssize_t error;
retry:
error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
if (error)
return error;
error = getxattr(mnt_idmap(path.mnt), path.dentry, name, value, size);
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
return error;
} }
SYSCALL_DEFINE4(getxattr, const char __user *, pathname, SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
@ -833,13 +838,22 @@ SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
void __user *, value, size_t, size) void __user *, value, size_t, size)
{ {
ssize_t error;
struct xattr_name kname;
struct kernel_xattr_ctx ctx = {
.value = value,
.size = size,
.kname = &kname,
.flags = 0,
};
CLASS(fd, f)(fd); CLASS(fd, f)(fd);
if (fd_empty(f)) if (fd_empty(f))
return -EBADF; return -EBADF;
audit_file(fd_file(f)); error = import_xattr_name(&kname, name);
return getxattr(file_mnt_idmap(fd_file(f)), fd_file(f)->f_path.dentry, if (error)
name, value, size); return error;
return file_getxattr(fd_file(f), &ctx);
} }
/* /*

31
io_uring/xattr.c
View File

@ -51,7 +51,7 @@ static int __io_getxattr_prep(struct io_kiocb *req,
ix->filename = NULL; ix->filename = NULL;
ix->ctx.kvalue = NULL; ix->ctx.kvalue = NULL;
name = u64_to_user_ptr(READ_ONCE(sqe->addr)); name = u64_to_user_ptr(READ_ONCE(sqe->addr));
ix->ctx.cvalue = u64_to_user_ptr(READ_ONCE(sqe->addr2)); ix->ctx.value = u64_to_user_ptr(READ_ONCE(sqe->addr2));
ix->ctx.size = READ_ONCE(sqe->len); ix->ctx.size = READ_ONCE(sqe->len);
ix->ctx.flags = READ_ONCE(sqe->xattr_flags); ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
@ -94,12 +94,10 @@ int io_getxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
path = u64_to_user_ptr(READ_ONCE(sqe->addr3)); path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
ix->filename = getname(path); ix->filename = getname(path);
if (IS_ERR(ix->filename)) { if (IS_ERR(ix->filename))
ret = PTR_ERR(ix->filename); return PTR_ERR(ix->filename);
ix->filename = NULL;
}
return ret; return 0;
} }
int io_fgetxattr(struct io_kiocb *req, unsigned int issue_flags) int io_fgetxattr(struct io_kiocb *req, unsigned int issue_flags)
@ -109,10 +107,7 @@ int io_fgetxattr(struct io_kiocb *req, unsigned int issue_flags)
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK); WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
ret = do_getxattr(file_mnt_idmap(req->file), ret = file_getxattr(req->file, &ix->ctx);
req->file->f_path.dentry,
&ix->ctx);
io_xattr_finish(req, ret); io_xattr_finish(req, ret);
return IOU_OK; return IOU_OK;
} }
@ -120,24 +115,12 @@ int io_fgetxattr(struct io_kiocb *req, unsigned int issue_flags)
int io_getxattr(struct io_kiocb *req, unsigned int issue_flags) int io_getxattr(struct io_kiocb *req, unsigned int issue_flags)
{ {
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr); struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
unsigned int lookup_flags = LOOKUP_FOLLOW;
struct path path;
int ret; int ret;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK); WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
retry: ret = filename_getxattr(AT_FDCWD, ix->filename, LOOKUP_FOLLOW, &ix->ctx);
ret = filename_lookup(AT_FDCWD, ix->filename, lookup_flags, &path, NULL); ix->filename = NULL;
if (!ret) {
ret = do_getxattr(mnt_idmap(path.mnt), path.dentry, &ix->ctx);
path_put(&path);
if (retry_estale(ret, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
}
io_xattr_finish(req, ret); io_xattr_finish(req, ret);
return IOU_OK; return IOU_OK;
} }