On Wed, Oct 02, 2024 at 02:22:30AM GMT, Al Viro wrote:
> From: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxxxx>
> Link: https://lore.kernel.org/r/20240426162042.191916-1-cgoettsche@xxxxxxxxxxxxx
> Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>
> CC: x86@xxxxxxxxxx
> CC: linux-alpha@xxxxxxxxxxxxxxx
> CC: linux-kernel@xxxxxxxxxxxxxxx
> CC: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> CC: linux-ia64@xxxxxxxxxxxxxxx
> CC: linux-m68k@xxxxxxxxxxxxxxxxxxxx
> CC: linux-mips@xxxxxxxxxxxxxxx
> CC: linux-parisc@xxxxxxxxxxxxxxx
> CC: linuxppc-dev@xxxxxxxxxxxxxxxx
> CC: linux-s390@xxxxxxxxxxxxxxx
> CC: linux-sh@xxxxxxxxxxxxxxx
> CC: sparclinux@xxxxxxxxxxxxxxx
> CC: linux-fsdevel@xxxxxxxxxxxxxxx
> CC: audit@xxxxxxxxxxxxxxx
> CC: linux-arch@xxxxxxxxxxxxxxx
> CC: linux-api@xxxxxxxxxxxxxxx
> CC: linux-security-module@xxxxxxxxxxxxxxx
> CC: selinux@xxxxxxxxxxxxxxx
> [brauner: slight tweaks]
> Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
> ---
Reviewed-by: Christian Brauner <brauner@xxxxxxxxxx>
> arch/alpha/kernel/syscalls/syscall.tbl | 4 +
> arch/arm/tools/syscall.tbl | 4 +
> arch/m68k/kernel/syscalls/syscall.tbl | 4 +
> arch/microblaze/kernel/syscalls/syscall.tbl | 4 +
> arch/mips/kernel/syscalls/syscall_n32.tbl | 4 +
> arch/mips/kernel/syscalls/syscall_n64.tbl | 4 +
> arch/mips/kernel/syscalls/syscall_o32.tbl | 4 +
> arch/parisc/kernel/syscalls/syscall.tbl | 4 +
> arch/powerpc/kernel/syscalls/syscall.tbl | 4 +
> arch/s390/kernel/syscalls/syscall.tbl | 4 +
> arch/sh/kernel/syscalls/syscall.tbl | 4 +
> arch/sparc/kernel/syscalls/syscall.tbl | 4 +
> arch/x86/entry/syscalls/syscall_32.tbl | 4 +
> arch/x86/entry/syscalls/syscall_64.tbl | 4 +
> arch/xtensa/kernel/syscalls/syscall.tbl | 4 +
> fs/xattr.c | 271 ++++++++++++++------
> include/asm-generic/audit_change_attr.h | 6 +
> include/linux/syscalls.h | 13 +
> include/linux/xattr.h | 4 +
> include/uapi/asm-generic/unistd.h | 11 +-
> include/uapi/linux/xattr.h | 7 +
> 21 files changed, 286 insertions(+), 86 deletions(-)
>
> diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
> index 74720667fe09..c59d53d6d3f3 100644
> --- a/arch/alpha/kernel/syscalls/syscall.tbl
> +++ b/arch/alpha/kernel/syscalls/syscall.tbl
> @@ -502,3 +502,7 @@
> 570 common lsm_set_self_attr sys_lsm_set_self_attr
> 571 common lsm_list_modules sys_lsm_list_modules
> 572 common mseal sys_mseal
> +573 common setxattrat sys_setxattrat
> +574 common getxattrat sys_getxattrat
> +575 common listxattrat sys_listxattrat
> +576 common removexattrat sys_removexattrat
> diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
> index 23c98203c40f..49eeb2ad8dbd 100644
> --- a/arch/arm/tools/syscall.tbl
> +++ b/arch/arm/tools/syscall.tbl
> @@ -477,3 +477,7 @@
> 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
> diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
> index 22a3cbd4c602..f5ed71f1910d 100644
> --- a/arch/m68k/kernel/syscalls/syscall.tbl
> +++ b/arch/m68k/kernel/syscalls/syscall.tbl
> @@ -462,3 +462,7 @@
> 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
> diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
> index 2b81a6bd78b2..680f568b77f2 100644
> --- a/arch/microblaze/kernel/syscalls/syscall.tbl
> +++ b/arch/microblaze/kernel/syscalls/syscall.tbl
> @@ -468,3 +468,7 @@
> 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
> diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
> index 953f5b7dc723..0b9b7e25b69a 100644
> --- a/arch/mips/kernel/syscalls/syscall_n32.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
> @@ -401,3 +401,7 @@
> 460 n32 lsm_set_self_attr sys_lsm_set_self_attr
> 461 n32 lsm_list_modules sys_lsm_list_modules
> 462 n32 mseal sys_mseal
> +463 n32 setxattrat sys_setxattrat
> +464 n32 getxattrat sys_getxattrat
> +465 n32 listxattrat sys_listxattrat
> +466 n32 removexattrat sys_removexattrat
> diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
> index 1464c6be6eb3..c844cd5cda62 100644
> --- a/arch/mips/kernel/syscalls/syscall_n64.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
> @@ -377,3 +377,7 @@
> 460 n64 lsm_set_self_attr sys_lsm_set_self_attr
> 461 n64 lsm_list_modules sys_lsm_list_modules
> 462 n64 mseal sys_mseal
> +463 n64 setxattrat sys_setxattrat
> +464 n64 getxattrat sys_getxattrat
> +465 n64 listxattrat sys_listxattrat
> +466 n64 removexattrat sys_removexattrat
> diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
> index 2439a2491cff..349b8aad1159 100644
> --- a/arch/mips/kernel/syscalls/syscall_o32.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
> @@ -450,3 +450,7 @@
> 460 o32 lsm_set_self_attr sys_lsm_set_self_attr
> 461 o32 lsm_list_modules sys_lsm_list_modules
> 462 o32 mseal sys_mseal
> +463 o32 setxattrat sys_setxattrat
> +464 o32 getxattrat sys_getxattrat
> +465 o32 listxattrat sys_listxattrat
> +466 o32 removexattrat sys_removexattrat
> diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
> index 66dc406b12e4..d9fc94c86965 100644
> --- a/arch/parisc/kernel/syscalls/syscall.tbl
> +++ b/arch/parisc/kernel/syscalls/syscall.tbl
> @@ -461,3 +461,7 @@
> 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
> diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
> index ebae8415dfbb..d8b4ab78bef0 100644
> --- a/arch/powerpc/kernel/syscalls/syscall.tbl
> +++ b/arch/powerpc/kernel/syscalls/syscall.tbl
> @@ -553,3 +553,7 @@
> 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
> diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
> index 01071182763e..e9115b4d8b63 100644
> --- a/arch/s390/kernel/syscalls/syscall.tbl
> +++ b/arch/s390/kernel/syscalls/syscall.tbl
> @@ -465,3 +465,7 @@
> 460 common lsm_set_self_attr sys_lsm_set_self_attr sys_lsm_set_self_attr
> 461 common lsm_list_modules sys_lsm_list_modules sys_lsm_list_modules
> 462 common mseal sys_mseal sys_mseal
> +463 common setxattrat sys_setxattrat sys_setxattrat
> +464 common getxattrat sys_getxattrat sys_getxattrat
> +465 common listxattrat sys_listxattrat sys_listxattrat
> +466 common removexattrat sys_removexattrat sys_removexattrat
> diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
> index c55fd7696d40..c8cad33bf250 100644
> --- a/arch/sh/kernel/syscalls/syscall.tbl
> +++ b/arch/sh/kernel/syscalls/syscall.tbl
> @@ -466,3 +466,7 @@
> 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
> diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
> index cfdfb3707c16..727f99d333b3 100644
> --- a/arch/sparc/kernel/syscalls/syscall.tbl
> +++ b/arch/sparc/kernel/syscalls/syscall.tbl
> @@ -508,3 +508,7 @@
> 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
> 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
> diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
> index 67083fc1b2f5..37effc1b134e 100644
> --- a/arch/xtensa/kernel/syscalls/syscall.tbl
> +++ b/arch/xtensa/kernel/syscalls/syscall.tbl
> @@ -433,3 +433,7 @@
> 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
> diff --git a/fs/xattr.c b/fs/xattr.c
> index 6f87f23c0e84..59cdb524412e 100644
> --- a/fs/xattr.c
> +++ b/fs/xattr.c
> @@ -597,6 +597,32 @@ int import_xattr_name(struct xattr_name *kname, const char __user *name)
> return 0;
> }
>
> +static struct filename *getname_xattr(const char __user *pathname,
> + unsigned int at_flags)
> +{
> + struct filename *name;
> + char c;
> +
> + if (!(at_flags & AT_EMPTY_PATH))
> + return getname(pathname);
> +
> + if (!pathname)
> + return NULL;
> +
> + /* try to save on allocations; will suck on s390 and um, though */
> + if (get_user(c, pathname))
> + return ERR_PTR(-EFAULT);
> + if (!c)
> + return NULL;
> +
> + name = getname_flags(pathname, LOOKUP_EMPTY);
> + if (!IS_ERR(name) && !(name->name[0])) {
> + putname(name);
> + name = NULL;
> + }
> + return name;
> +}
> +
> /*
> * Extended attribute SET operations
> */
> @@ -675,69 +701,90 @@ int filename_setxattr(int dfd, struct filename *filename,
> return error;
> }
>
> -static int path_setxattr(const char __user *pathname,
> - const char __user *name, const void __user *value,
> - size_t size, int flags, unsigned int lookup_flags)
> +static int path_setxattrat(int dfd, const char __user *pathname,
> + unsigned int at_flags, const char __user *name,
> + const void __user *value, size_t size, int flags)
> {
> struct xattr_name kname;
> struct kernel_xattr_ctx ctx = {
> - .cvalue = value,
> - .kvalue = NULL,
> - .size = size,
> - .kname = &kname,
> - .flags = flags,
> + .cvalue = value,
> + .kvalue = NULL,
> + .size = size,
> + .kname = &kname,
> + .flags = flags,
> };
> + struct filename *filename;
> + unsigned int lookup_flags = 0;
> int error;
>
> + if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
> + return -EINVAL;
> +
> + if (at_flags & AT_SYMLINK_NOFOLLOW)
> + lookup_flags = LOOKUP_FOLLOW;
> +
> error = setxattr_copy(name, &ctx);
> if (error)
> return error;
>
> - error = filename_setxattr(AT_FDCWD, getname(pathname), lookup_flags,
> - &ctx);
> + filename = getname_xattr(pathname, at_flags);
> + if (!filename) {
> + CLASS(fd, f)(dfd);
> + if (fd_empty(f))
> + error = -EBADF;
> + else
> + error = file_setxattr(fd_file(f), &ctx);
> + } else {
> + error = filename_setxattr(dfd, filename, lookup_flags, &ctx);
> + }
> kvfree(ctx.kvalue);
> return error;
> }
>
> +SYSCALL_DEFINE6(setxattrat, int, dfd, const char __user *, pathname, unsigned int, at_flags,
> + const char __user *, name, const struct xattr_args __user *, uargs,
> + size_t, usize)
> +{
> + struct xattr_args args = {};
> + int error;
> +
> + BUILD_BUG_ON(sizeof(struct xattr_args) < XATTR_ARGS_SIZE_VER0);
> + BUILD_BUG_ON(sizeof(struct xattr_args) != XATTR_ARGS_SIZE_LATEST);
> +
> + if (unlikely(usize < XATTR_ARGS_SIZE_VER0))
> + return -EINVAL;
> + if (usize > PAGE_SIZE)
> + return -E2BIG;
> +
> + error = copy_struct_from_user(&args, sizeof(args), uargs, usize);
> + if (error)
> + return error;
> +
> + return path_setxattrat(dfd, pathname, at_flags, name,
> + u64_to_user_ptr(args.value), args.size,
> + args.flags);
> +}
> +
> SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
> const char __user *, name, const void __user *, value,
> size_t, size, int, flags)
> {
> - return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW);
> + return path_setxattrat(AT_FDCWD, pathname, 0, name, value, size, flags);
> }
>
> SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
> const char __user *, name, const void __user *, value,
> size_t, size, int, flags)
> {
> - return path_setxattr(pathname, name, value, size, flags, 0);
> + return path_setxattrat(AT_FDCWD, pathname, AT_SYMLINK_NOFOLLOW, name,
> + value, size, flags);
> }
>
> SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
> const void __user *,value, size_t, size, int, flags)
> {
> - struct xattr_name kname;
> - struct kernel_xattr_ctx ctx = {
> - .cvalue = value,
> - .kvalue = NULL,
> - .size = size,
> - .kname = &kname,
> - .flags = flags,
> - };
> - int error;
> -
> - CLASS(fd, f)(fd);
> -
> - if (fd_empty(f))
> - return -EBADF;
> -
> - error = setxattr_copy(name, &ctx);
> - if (error)
> - return error;
> -
> - error = file_setxattr(fd_file(f), &ctx);
> - kvfree(ctx.kvalue);
> - return error;
> + return path_setxattrat(fd, NULL, AT_EMPTY_PATH, name,
> + value, size, flags);
> }
>
> /*
> @@ -802,11 +849,10 @@ ssize_t filename_getxattr(int dfd, struct filename *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)
> +static ssize_t path_getxattrat(int dfd, const char __user *pathname,
> + unsigned int at_flags, const char __user *name,
> + void __user *value, size_t size)
> {
> - ssize_t error;
> struct xattr_name kname;
> struct kernel_xattr_ctx ctx = {
> .value = value,
> @@ -814,44 +860,72 @@ static ssize_t path_getxattr(const char __user *pathname,
> .kname = &kname,
> .flags = 0,
> };
> + struct filename *filename;
> + ssize_t error;
> +
> + if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
> + return -EINVAL;
>
> error = import_xattr_name(&kname, name);
> if (error)
> return error;
> - return filename_getxattr(AT_FDCWD, getname(pathname), lookup_flags, &ctx);
> +
> + filename = getname_xattr(pathname, at_flags);
> + if (!filename) {
> + CLASS(fd, f)(dfd);
> + if (fd_empty(f))
> + return -EBADF;
> + return file_getxattr(fd_file(f), &ctx);
> + } else {
> + int lookup_flags = 0;
> + if (at_flags & AT_SYMLINK_NOFOLLOW)
> + lookup_flags = LOOKUP_FOLLOW;
> + return filename_getxattr(dfd, filename, lookup_flags, &ctx);
> + }
> +}
> +
> +SYSCALL_DEFINE6(getxattrat, int, dfd, const char __user *, pathname, unsigned int, at_flags,
> + const char __user *, name, struct xattr_args __user *, uargs, size_t, usize)
> +{
> + struct xattr_args args = {};
> + int error;
> +
> + BUILD_BUG_ON(sizeof(struct xattr_args) < XATTR_ARGS_SIZE_VER0);
> + BUILD_BUG_ON(sizeof(struct xattr_args) != XATTR_ARGS_SIZE_LATEST);
> +
> + if (unlikely(usize < XATTR_ARGS_SIZE_VER0))
> + return -EINVAL;
> + if (usize > PAGE_SIZE)
> + return -E2BIG;
> +
> + error = copy_struct_from_user(&args, sizeof(args), uargs, usize);
> + if (error)
> + return error;
> +
> + if (args.flags != 0)
> + return -EINVAL;
> +
> + return path_getxattrat(dfd, pathname, at_flags, name,
> + u64_to_user_ptr(args.value), args.size);
> }
>
> SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
> const char __user *, name, void __user *, value, size_t, size)
> {
> - return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW);
> + return path_getxattrat(AT_FDCWD, pathname, 0, name, value, size);
> }
>
> SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
> const char __user *, name, void __user *, value, size_t, size)
> {
> - return path_getxattr(pathname, name, value, size, 0);
> + return path_getxattrat(AT_FDCWD, pathname, AT_SYMLINK_NOFOLLOW, name,
> + value, size);
> }
>
> SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
> 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);
> -
> - if (fd_empty(f))
> - return -EBADF;
> - error = import_xattr_name(&kname, name);
> - if (error)
> - return error;
> - return file_getxattr(fd_file(f), &ctx);
> + return path_getxattrat(fd, NULL, AT_EMPTY_PATH, name, value, size);
> }
>
> /*
> @@ -915,32 +989,50 @@ ssize_t filename_listxattr(int dfd, struct filename *filename,
> return error;
> }
>
> -static ssize_t path_listxattr(const char __user *pathname, char __user *list,
> - size_t size, unsigned int lookup_flags)
> +static ssize_t path_listxattrat(int dfd, const char __user *pathname,
> + unsigned int at_flags, char __user *list,
> + size_t size)
> +{
> + struct filename *filename;
> + int lookup_flags;
> +
> + if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
> + return -EINVAL;
> +
> + filename = getname_xattr(pathname, at_flags);
> + if (!filename) {
> + CLASS(fd, f)(dfd);
> + if (fd_empty(f))
> + return -EBADF;
> + return file_listxattr(fd_file(f), list, size);
> + }
> +
> + lookup_flags = (at_flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
> + return filename_listxattr(dfd, filename, lookup_flags, list, size);
> +}
> +
> +SYSCALL_DEFINE5(listxattrat, int, dfd, const char __user *, pathname,
> + unsigned int, at_flags,
> + char __user *, list, size_t, size)
> {
> - return filename_listxattr(AT_FDCWD, getname(pathname), lookup_flags,
> - list, size);
> + return path_listxattrat(dfd, pathname, at_flags, list, size);
> }
>
> SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
> size_t, size)
> {
> - return path_listxattr(pathname, list, size, LOOKUP_FOLLOW);
> + return path_listxattrat(AT_FDCWD, pathname, 0, list, size);
> }
>
> SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
> size_t, size)
> {
> - return path_listxattr(pathname, list, size, 0);
> + return path_listxattrat(AT_FDCWD, pathname, AT_SYMLINK_NOFOLLOW, list, size);
> }
>
> SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
> {
> - CLASS(fd, f)(fd);
> -
> - if (fd_empty(f))
> - return -EBADF;
> - return file_listxattr(fd_file(f), list, size);
> + return path_listxattrat(fd, NULL, AT_EMPTY_PATH, list, size);
> }
>
> /*
> @@ -992,44 +1084,53 @@ static int filename_removexattr(int dfd, struct filename *filename,
> return error;
> }
>
> -static int path_removexattr(const char __user *pathname,
> - const char __user *name, unsigned int lookup_flags)
> +static int path_removexattrat(int dfd, const char __user *pathname,
> + unsigned int at_flags, const char __user *name)
> {
> struct xattr_name kname;
> + struct filename *filename;
> + unsigned int lookup_flags;
> int error;
>
> + if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
> + return -EINVAL;
> +
> error = import_xattr_name(&kname, name);
> if (error)
> return error;
> - return filename_removexattr(AT_FDCWD, getname(pathname), lookup_flags,
> - &kname);
> +
> + filename = getname_xattr(pathname, at_flags);
> + if (!filename) {
> + CLASS(fd, f)(dfd);
> + if (fd_empty(f))
> + return -EBADF;
> + return file_removexattr(fd_file(f), &kname);
> + }
> + lookup_flags = (at_flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
> + return filename_removexattr(dfd, filename, lookup_flags, &kname);
> +}
> +
> +SYSCALL_DEFINE4(removexattrat, int, dfd, const char __user *, pathname,
> + unsigned int, at_flags, const char __user *, name)
> +{
> + return path_removexattrat(dfd, pathname, at_flags, name);
> }
>
> SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
> const char __user *, name)
> {
> - return path_removexattr(pathname, name, LOOKUP_FOLLOW);
> + return path_removexattrat(AT_FDCWD, pathname, 0, name);
> }
>
> SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
> const char __user *, name)
> {
> - return path_removexattr(pathname, name, 0);
> + return path_removexattrat(AT_FDCWD, pathname, AT_SYMLINK_NOFOLLOW, name);
> }
>
> SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
> {
> - CLASS(fd, f)(fd);
> - struct xattr_name kname;
> - int error;
> -
> - if (fd_empty(f))
> - return -EBADF;
> -
> - error = import_xattr_name(&kname, name);
> - if (error)
> - return error;
> - return file_removexattr(fd_file(f), &kname);
> + return path_removexattrat(fd, NULL, AT_EMPTY_PATH, name);
> }
>
> int xattr_list_one(char **buffer, ssize_t *remaining_size, const char *name)
> diff --git a/include/asm-generic/audit_change_attr.h b/include/asm-generic/audit_change_attr.h
> index 331670807cf0..cc840537885f 100644
> --- a/include/asm-generic/audit_change_attr.h
> +++ b/include/asm-generic/audit_change_attr.h
> @@ -11,9 +11,15 @@ __NR_lchown,
> __NR_fchown,
> #endif
> __NR_setxattr,
> +#ifdef __NR_setxattrat
> +__NR_setxattrat,
> +#endif
> __NR_lsetxattr,
> __NR_fsetxattr,
> __NR_removexattr,
> +#ifdef __NR_removexattrat
> +__NR_removexattrat,
> +#endif
> __NR_lremovexattr,
> __NR_fremovexattr,
> #ifdef __NR_fchownat
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 5758104921e6..c6333204d451 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -77,6 +77,7 @@ struct cachestat_range;
> struct cachestat;
> struct statmount;
> struct mnt_id_req;
> +struct xattr_args;
>
> #include <linux/types.h>
> #include <linux/aio_abi.h>
> @@ -338,23 +339,35 @@ asmlinkage long sys_io_uring_register(unsigned int fd, unsigned int op,
> void __user *arg, unsigned int nr_args);
> asmlinkage long sys_setxattr(const char __user *path, const char __user *name,
> const void __user *value, size_t size, int flags);
> +asmlinkage long sys_setxattrat(int dfd, const char __user *path, unsigned int at_flags,
> + const char __user *name,
> + const struct xattr_args __user *args, size_t size);
> asmlinkage long sys_lsetxattr(const char __user *path, const char __user *name,
> const void __user *value, size_t size, int flags);
> asmlinkage long sys_fsetxattr(int fd, const char __user *name,
> const void __user *value, size_t size, int flags);
> asmlinkage long sys_getxattr(const char __user *path, const char __user *name,
> void __user *value, size_t size);
> +asmlinkage long sys_getxattrat(int dfd, const char __user *path, unsigned int at_flags,
> + const char __user *name,
> + struct xattr_args __user *args, size_t size);
> asmlinkage long sys_lgetxattr(const char __user *path, const char __user *name,
> void __user *value, size_t size);
> asmlinkage long sys_fgetxattr(int fd, const char __user *name,
> void __user *value, size_t size);
> asmlinkage long sys_listxattr(const char __user *path, char __user *list,
> size_t size);
> +asmlinkage long sys_listxattrat(int dfd, const char __user *path,
> + unsigned int at_flags,
> + char __user *list, size_t size);
> asmlinkage long sys_llistxattr(const char __user *path, char __user *list,
> size_t size);
> asmlinkage long sys_flistxattr(int fd, char __user *list, size_t size);
> asmlinkage long sys_removexattr(const char __user *path,
> const char __user *name);
> +asmlinkage long sys_removexattrat(int dfd, const char __user *path,
> + unsigned int at_flags,
> + const char __user *name);
> asmlinkage long sys_lremovexattr(const char __user *path,
> const char __user *name);
> asmlinkage long sys_fremovexattr(int fd, const char __user *name);
> diff --git a/include/linux/xattr.h b/include/linux/xattr.h
> index d20051865800..86b0d47984a1 100644
> --- a/include/linux/xattr.h
> +++ b/include/linux/xattr.h
> @@ -19,6 +19,10 @@
> #include <linux/user_namespace.h>
> #include <uapi/linux/xattr.h>
>
> +/* List of all open_how "versions". */
> +#define XATTR_ARGS_SIZE_VER0 16 /* sizeof first published struct */
> +#define XATTR_ARGS_SIZE_LATEST XATTR_ARGS_SIZE_VER0
> +
> struct inode;
> struct dentry;
>
> diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
> index 5bf6148cac2b..88dc393c2bca 100644
> --- a/include/uapi/asm-generic/unistd.h
> +++ b/include/uapi/asm-generic/unistd.h
> @@ -841,8 +841,17 @@ __SYSCALL(__NR_lsm_list_modules, sys_lsm_list_modules)
> #define __NR_mseal 462
> __SYSCALL(__NR_mseal, sys_mseal)
>
> +#define __NR_setxattrat 463
> +__SYSCALL(__NR_setxattrat, sys_setxattrat)
> +#define __NR_getxattrat 464
> +__SYSCALL(__NR_getxattrat, sys_getxattrat)
> +#define __NR_listxattrat 465
> +__SYSCALL(__NR_listxattrat, sys_listxattrat)
> +#define __NR_removexattrat 466
> +__SYSCALL(__NR_removexattrat, sys_removexattrat)
> +
> #undef __NR_syscalls
> -#define __NR_syscalls 463
> +#define __NR_syscalls 467
>
> /*
> * 32 bit systems traditionally used different
> 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 */
> --
> 2.39.5
>
