From: Stefan Roesch <[email protected]>
To: <[email protected]>, <[email protected]>,
<[email protected]>
Cc: <[email protected]>, <[email protected]>,
<[email protected]>
Subject: [PATCH v10 2/5] fs: split off setxattr_copy and do_setxattr function from setxattr
Date: Wed, 29 Dec 2021 12:29:59 -0800 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
This splits of the setup part of the function
setxattr in its own dedicated function called
setxattr_copy. In addition it also exposes a
new function called do_setxattr for making the
setxattr call.
This makes it possible to call these two functions
from io_uring in the processing of an xattr request.
Signed-off-by: Stefan Roesch <[email protected]>
Acked-by: Christian Brauner <[email protected]>
---
fs/internal.h | 21 +++++++++++++
fs/xattr.c | 82 ++++++++++++++++++++++++++++++++++++---------------
2 files changed, 80 insertions(+), 23 deletions(-)
diff --git a/fs/internal.h b/fs/internal.h
index afa60757d5f6..07487f29feb0 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -208,3 +208,24 @@ int vfs_getdents(struct file *file, struct linux_dirent64 __user *dirent,
*/
extern int do_user_path_at_empty(int dfd, struct filename *filename,
unsigned int flags, struct path *path);
+
+ /*
+ * fs/xattr.c:
+ */
+struct xattr_name {
+ char name[XATTR_NAME_MAX + 1];
+};
+
+struct xattr_ctx {
+ /* Value of attribute */
+ const void __user *value;
+ void *kvalue;
+ size_t size;
+ /* Attribute name */
+ struct xattr_name *kname;
+ unsigned int flags;
+};
+
+int setxattr_copy(const char __user *name, struct xattr_ctx *ctx);
+int do_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+ struct xattr_ctx *ctx);
diff --git a/fs/xattr.c b/fs/xattr.c
index 5c8c5175b385..923ba944d20e 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -25,6 +25,8 @@
#include <linux/uaccess.h>
+#include "internal.h"
+
static const char *
strcmp_prefix(const char *a, const char *a_prefix)
{
@@ -539,43 +541,77 @@ EXPORT_SYMBOL_GPL(vfs_removexattr);
/*
* Extended attribute SET operations
*/
-static long
-setxattr(struct user_namespace *mnt_userns, struct dentry *d,
- const char __user *name, const void __user *value, size_t size,
- int flags)
+
+int setxattr_copy(const char __user *name, struct xattr_ctx *ctx)
{
int error;
- void *kvalue = NULL;
- char kname[XATTR_NAME_MAX + 1];
- if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
+ if (ctx->flags & ~(XATTR_CREATE|XATTR_REPLACE))
return -EINVAL;
- error = strncpy_from_user(kname, name, sizeof(kname));
- if (error == 0 || error == sizeof(kname))
- error = -ERANGE;
+ error = strncpy_from_user(ctx->kname->name, name,
+ sizeof(ctx->kname->name));
+ if (error == 0 || error == sizeof(ctx->kname->name))
+ return -ERANGE;
if (error < 0)
return error;
- if (size) {
- if (size > XATTR_SIZE_MAX)
+ if (ctx->size) {
+ if (ctx->size > XATTR_SIZE_MAX)
return -E2BIG;
- kvalue = kvmalloc(size, GFP_KERNEL);
- if (!kvalue)
+
+ ctx->kvalue = kvmalloc(ctx->size, GFP_KERNEL);
+ if (!ctx->kvalue)
return -ENOMEM;
- if (copy_from_user(kvalue, value, size)) {
- error = -EFAULT;
- goto out;
+
+ if (copy_from_user(ctx->kvalue, ctx->value, ctx->size)) {
+ kvfree(ctx->kvalue);
+ return -EFAULT;
}
- if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
- (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
- posix_acl_fix_xattr_from_user(mnt_userns, kvalue, size);
}
- error = vfs_setxattr(mnt_userns, d, kname, kvalue, size, flags);
-out:
- kvfree(kvalue);
+ return 0;
+}
+
+static void setxattr_convert(struct user_namespace *mnt_userns,
+ struct xattr_ctx *ctx)
+{
+ if (ctx->size &&
+ ((strcmp(ctx->kname->name, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
+ (strcmp(ctx->kname->name, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)))
+ posix_acl_fix_xattr_from_user(mnt_userns, ctx->kvalue, ctx->size);
+}
+
+int do_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+ struct xattr_ctx *ctx)
+{
+ setxattr_convert(mnt_userns, ctx);
+ return vfs_setxattr(mnt_userns, dentry, ctx->kname->name,
+ ctx->kvalue, ctx->size, ctx->flags);
+}
+
+static long
+setxattr(struct user_namespace *mnt_userns, struct dentry *d,
+ const char __user *name, const void __user *value, size_t size,
+ int flags)
+{
+ struct xattr_name kname;
+ struct xattr_ctx ctx = {
+ .value = value,
+ .kvalue = NULL,
+ .size = size,
+ .kname = &kname,
+ .flags = flags,
+ };
+ int error;
+
+ error = setxattr_copy(name, &ctx);
+ if (error)
+ return error;
+
+ error = do_setxattr(mnt_userns, d, &ctx);
+ kvfree(ctx.kvalue);
return error;
}
--
2.30.2
next prev parent reply other threads:[~2021-12-29 20:32 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-29 20:29 [PATCH v10 0/5] io_uring: add xattr support Stefan Roesch
2021-12-29 20:29 ` [PATCH v10 1/5] fs: split off do_user_path_at_empty from user_path_at_empty() Stefan Roesch
2021-12-30 0:49 ` Al Viro
2021-12-30 19:57 ` Stefan Roesch
2021-12-29 20:29 ` Stefan Roesch [this message]
2021-12-30 1:15 ` [PATCH v10 2/5] fs: split off setxattr_copy and do_setxattr function from setxattr Al Viro
2021-12-30 9:41 ` Christian Brauner
2021-12-30 19:57 ` Stefan Roesch
2021-12-29 20:30 ` [PATCH v10 3/5] fs: split off do_getxattr from getxattr Stefan Roesch
2021-12-29 20:30 ` [PATCH v10 4/5] io_uring: add fsetxattr and setxattr support Stefan Roesch
2021-12-30 1:58 ` Al Viro
2021-12-30 2:17 ` Al Viro
2021-12-30 2:19 ` Al Viro
2021-12-30 3:04 ` Al Viro
2021-12-30 10:12 ` Christian Brauner
2021-12-30 16:16 ` Al Viro
2021-12-30 18:01 ` Christian Brauner
2021-12-30 19:09 ` Jens Axboe
2021-12-30 22:24 ` Al Viro
2021-12-30 22:46 ` Jens Axboe
2021-12-30 23:02 ` Al Viro
2021-12-30 20:18 ` Stefan Roesch
2021-12-29 20:30 ` [PATCH v10 5/5] io_uring: add fgetxattr and getxattr support Stefan Roesch
2021-12-30 1:41 ` Al Viro
2021-12-30 1:46 ` Al Viro
2021-12-30 20:01 ` Stefan Roesch
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