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 /arch/x86 | |
| 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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CC: linux-kernel@vger.kernel.org
CC: linux-arm-kernel@lists.infradead.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 'arch/x86')
| -rw-r--r-- | arch/x86/entry/syscalls/syscall_32.tbl | 4 | ||||
| -rw-r--r-- | arch/x86/entry/syscalls/syscall_64.tbl | 4 |
2 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index 534c74b14fab..4d0fb2fba7e2 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -468,3 +468,7 @@ 460 i386 lsm_set_self_attr sys_lsm_set_self_attr 461 i386 lsm_list_modules sys_lsm_list_modules 462 i386 mseal sys_mseal +463 i386 setxattrat sys_setxattrat +464 i386 getxattrat sys_getxattrat +465 i386 listxattrat sys_listxattrat +466 i386 removexattrat sys_removexattrat diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 7093ee21c0d1..5eb708bff1c7 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -386,6 +386,10 @@ 460 common lsm_set_self_attr sys_lsm_set_self_attr 461 common lsm_list_modules sys_lsm_list_modules 462 common mseal sys_mseal +463 common setxattrat sys_setxattrat +464 common getxattrat sys_getxattrat +465 common listxattrat sys_listxattrat +466 common removexattrat sys_removexattrat # # Due to a historical design error, certain syscalls are numbered differently |