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cgzonesAl Viro
cgzones
authored and
Al Viro
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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 <[email protected]> Link: https://lore.kernel.org/r/[email protected] Reviewed-by: Arnd Bergmann <[email protected]> Reviewed-by: Christian Brauner <[email protected]> CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] [brauner: slight tweaks] Signed-off-by: Christian Brauner <[email protected]> Signed-off-by: Al Viro <[email protected]>
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23 files changed

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lines changed

23 files changed

+268
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lines changed

‎arch/alpha/kernel/syscalls/syscall.tbl

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570 common lsm_set_self_attr sys_lsm_set_self_attr
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571 common lsm_list_modules sys_lsm_list_modules
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572 common mseal sys_mseal
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573 common setxattrat sys_setxattrat
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574 common getxattrat sys_getxattrat
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575 common listxattrat sys_listxattrat
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576 common removexattrat sys_removexattrat

‎arch/arm/tools/syscall.tbl

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460 common lsm_set_self_attr sys_lsm_set_self_attr
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461 common lsm_list_modules sys_lsm_list_modules
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462 common mseal sys_mseal
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463 common setxattrat sys_setxattrat
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464 common getxattrat sys_getxattrat
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465 common listxattrat sys_listxattrat
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466 common removexattrat sys_removexattrat

‎arch/arm64/tools/syscall_32.tbl

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460 common lsm_set_self_attr sys_lsm_set_self_attr
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461 common lsm_list_modules sys_lsm_list_modules
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462 common mseal sys_mseal
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463 common setxattrat sys_setxattrat
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464 common getxattrat sys_getxattrat
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465 common listxattrat sys_listxattrat
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466 common removexattrat sys_removexattrat

‎arch/m68k/kernel/syscalls/syscall.tbl

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460 common lsm_set_self_attr sys_lsm_set_self_attr
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461 common lsm_list_modules sys_lsm_list_modules
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462 common mseal sys_mseal
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463 common setxattrat sys_setxattrat
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464 common getxattrat sys_getxattrat
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465 common listxattrat sys_listxattrat
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466 common removexattrat sys_removexattrat

‎arch/microblaze/kernel/syscalls/syscall.tbl

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460 common lsm_set_self_attr sys_lsm_set_self_attr
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461 common lsm_list_modules sys_lsm_list_modules
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462 common mseal sys_mseal
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463 common setxattrat sys_setxattrat
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464 common getxattrat sys_getxattrat
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465 common listxattrat sys_listxattrat
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466 common removexattrat sys_removexattrat

‎arch/mips/kernel/syscalls/syscall_n32.tbl

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460 n32 lsm_set_self_attr sys_lsm_set_self_attr
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461 n32 lsm_list_modules sys_lsm_list_modules
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462 n32 mseal sys_mseal
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463 n32 setxattrat sys_setxattrat
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464 n32 getxattrat sys_getxattrat
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465 n32 listxattrat sys_listxattrat
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466 n32 removexattrat sys_removexattrat

‎arch/mips/kernel/syscalls/syscall_n64.tbl

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460 n64 lsm_set_self_attr sys_lsm_set_self_attr
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461 n64 lsm_list_modules sys_lsm_list_modules
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462 n64 mseal sys_mseal
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463 n64 setxattrat sys_setxattrat
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464 n64 getxattrat sys_getxattrat
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465 n64 listxattrat sys_listxattrat
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466 n64 removexattrat sys_removexattrat

‎arch/mips/kernel/syscalls/syscall_o32.tbl

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460 o32 lsm_set_self_attr sys_lsm_set_self_attr
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461 o32 lsm_list_modules sys_lsm_list_modules
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462 o32 mseal sys_mseal
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463 o32 setxattrat sys_setxattrat
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464 o32 getxattrat sys_getxattrat
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465 o32 listxattrat sys_listxattrat
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466 o32 removexattrat sys_removexattrat

‎arch/parisc/kernel/syscalls/syscall.tbl

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460 common lsm_set_self_attr sys_lsm_set_self_attr
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461 common lsm_list_modules sys_lsm_list_modules
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462 common mseal sys_mseal
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463 common setxattrat sys_setxattrat
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464 common getxattrat sys_getxattrat
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465 common listxattrat sys_listxattrat
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466 common removexattrat sys_removexattrat

‎arch/powerpc/kernel/syscalls/syscall.tbl

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460 common lsm_set_self_attr sys_lsm_set_self_attr
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461 common lsm_list_modules sys_lsm_list_modules
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462 common mseal sys_mseal
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463 common setxattrat sys_setxattrat
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464 common getxattrat sys_getxattrat
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465 common listxattrat sys_listxattrat
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466 common removexattrat sys_removexattrat

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