diff options
| author | Christian Göttsche <cgzones@googlemail.com> | 2024-04-26 18:20:14 +0200 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2024-11-06 12:59:44 -0500 |
| commit | 6140be90ec70c39fa844741ca3cc807dd0866394 (patch) | |
| tree | ee8da12714f8705b50eb5b66abaa78ba43626a58 /include/uapi/linux | |
| parent | 22a4d1954cf5d51d5aa82eccb0b5fd4d8be92551 (diff) | |
fs/xattr: add *at family syscalls
Add the four syscalls setxattrat(), getxattrat(), listxattrat() and
removexattrat(). Those can be used to operate on extended attributes,
especially security related ones, either relative to a pinned directory
or on a file descriptor without read access, avoiding a
/proc/<pid>/fd/<fd> detour, requiring a mounted procfs.
One use case will be setfiles(8) setting SELinux file contexts
("security.selinux") without race conditions and without a file
descriptor opened with read access requiring SELinux read permission.
Use the do_{name}at() pattern from fs/open.c.
Pass the value of the extended attribute, its length, and for
setxattrat(2) the command (XATTR_CREATE or XATTR_REPLACE) via an added
struct xattr_args to not exceed six syscall arguments and not
merging the AT_* and XATTR_* flags.
[AV: fixes by Christian Brauner folded in, the entire thing rebased on
top of {filename,file}_...xattr() primitives, treatment of empty
pathnames regularized. As the result, AT_EMPTY_PATH+NULL handling
is cheap, so f...(2) can use it]
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Link: https://lore.kernel.org/r/20240426162042.191916-1-cgoettsche@seltendoof.de
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
CC: x86@kernel.org
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[brauner: slight tweaks]
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/uapi/linux')
| -rw-r--r-- | include/uapi/linux/xattr.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/uapi/linux/xattr.h b/include/uapi/linux/xattr.h index 9463db2dfa9d..9854f9cff3c6 100644 --- a/include/uapi/linux/xattr.h +++ b/include/uapi/linux/xattr.h @@ -11,6 +11,7 @@ */ #include <linux/libc-compat.h> +#include <linux/types.h> #ifndef _UAPI_LINUX_XATTR_H #define _UAPI_LINUX_XATTR_H @@ -20,6 +21,12 @@ #define XATTR_CREATE 0x1 /* set value, fail if attr already exists */ #define XATTR_REPLACE 0x2 /* set value, fail if attr does not exist */ + +struct xattr_args { + __aligned_u64 __user value; + __u32 size; + __u32 flags; +}; #endif /* Namespaces */ |