Mailing List Archive

From: Christian Göttsche <cgzones@googlemail.com>

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.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
CC: x86@kernel.org
CC: linux-alpha@vger.kernel.org
CC: linux-kernel@vger.kernel.org
CC: linux-arm-kernel@lists.infradead.org
CC: linux-ia64@vger.kernel.org
CC: linux-m68k@lists.linux-m68k.org
CC: linux-mips@vger.kernel.org
CC: linux-parisc@vger.kernel.org
CC: linuxppc-dev@lists.ozlabs.org
CC: linux-s390@vger.kernel.org
CC: linux-sh@vger.kernel.org
CC: sparclinux@vger.kernel.org
CC: linux-fsdevel@vger.kernel.org
CC: audit@vger.kernel.org
CC: linux-arch@vger.kernel.org
CC: linux-api@vger.kernel.org
CC: linux-security-module@vger.kernel.org
CC: selinux@vger.kernel.org
---
v3:
- pass value, size and xattr_flags via new struct xattr_args to
split AT_* and XATTR_* flags

v2: https://lore.kernel.org/lkml/20230511150802.737477-1-cgzones@googlemail.com/
- squash syscall introduction and wire up commits
- add AT_XATTR_CREATE and AT_XATTR_REPLACE constants

v1 discussion: https://lore.kernel.org/all/20220830152858.14866-2-cgzones@googlemail.com/

Previous approach ("f*xattr: allow O_PATH descriptors"): https://lore.kernel.org/all/20220607153139.35588-1-cgzones@googlemail.com/
---
arch/alpha/kernel/syscalls/syscall.tbl | 4 +
arch/arm/tools/syscall.tbl | 4 +
arch/arm64/include/asm/unistd.h | 2 +-
arch/arm64/include/asm/unistd32.h | 8 ++
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 | 128 ++++++++++++++++----
include/asm-generic/audit_change_attr.h | 6 +
include/linux/syscalls.h | 10 ++
include/uapi/asm-generic/unistd.h | 12 +-
include/uapi/linux/xattr.h | 6 +
22 files changed, 208 insertions(+), 24 deletions(-)

diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 8ff110826ce2..fdc11249f1b8 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -501,3 +501,7 @@
569 common lsm_get_self_attr sys_lsm_get_self_attr
570 common lsm_set_self_attr sys_lsm_set_self_attr
571 common lsm_list_modules sys_lsm_list_modules
+572 common setxattrat sys_setxattrat
+573 common getxattrat sys_getxattrat
+574 common listxattrat sys_listxattrat
+575 common removexattrat sys_removexattrat
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index b6c9e01e14f5..22fbbcd8e2b5 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -475,3 +475,7 @@
459 common lsm_get_self_attr sys_lsm_get_self_attr
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
+462 common setxattrat sys_setxattrat
+463 common getxattrat sys_getxattrat
+464 common listxattrat sys_listxattrat
+465 common removexattrat sys_removexattrat
diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
index 491b2b9bd553..f3a77719eb05 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -39,7 +39,7 @@
#define __ARM_NR_compat_set_tls (__ARM_NR_COMPAT_BASE + 5)
#define __ARM_NR_COMPAT_END (__ARM_NR_COMPAT_BASE + 0x800)

-#define __NR_compat_syscalls 462
+#define __NR_compat_syscalls 466
#endif

#define __ARCH_WANT_SYS_CLONE
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index 7118282d1c79..963c999b8d2e 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -929,6 +929,14 @@ __SYSCALL(__NR_lsm_get_self_attr, sys_lsm_get_self_attr)
__SYSCALL(__NR_lsm_set_self_attr, sys_lsm_set_self_attr)
#define __NR_lsm_list_modules 461
__SYSCALL(__NR_lsm_list_modules, sys_lsm_list_modules)
+#define __NR_setxattrat 462
+__SYSCALL(__NR_setxattrat, sys_setxattrat)
+#define __NR_getxattrat 463
+__SYSCALL(__NR_getxattrat, sys_getxattrat)
+#define __NR_listxattrat 464
+__SYSCALL(__NR_listxattrat, sys_listxattrat)
+#define __NR_removexattrat 465
+__SYSCALL(__NR_removexattrat, sys_removexattrat)

/*
* Please add new compat syscalls above this comment and update
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index 7fd43fd4c9f2..7e8e2d9c3b81 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -461,3 +461,7 @@
459 common lsm_get_self_attr sys_lsm_get_self_attr
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
+462 common setxattrat sys_setxattrat
+463 common getxattrat sys_getxattrat
+464 common listxattrat sys_listxattrat
+465 common removexattrat sys_removexattrat
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index b00ab2cabab9..7df7fc7c0528 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -467,3 +467,7 @@
459 common lsm_get_self_attr sys_lsm_get_self_attr
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
+462 common setxattrat sys_setxattrat
+463 common getxattrat sys_getxattrat
+464 common listxattrat sys_listxattrat
+465 common removexattrat sys_removexattrat
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index 83cfc9eb6b88..07141274f9ff 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -400,3 +400,7 @@
459 n32 lsm_get_self_attr sys_lsm_get_self_attr
460 n32 lsm_set_self_attr sys_lsm_set_self_attr
461 n32 lsm_list_modules sys_lsm_list_modules
+462 n32 setxattrat sys_setxattrat
+463 n32 getxattrat sys_getxattrat
+464 n32 listxattrat sys_listxattrat
+465 n32 removexattrat sys_removexattrat
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index 532b855df589..9773412f2812 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -376,3 +376,7 @@
459 n64 lsm_get_self_attr sys_lsm_get_self_attr
460 n64 lsm_set_self_attr sys_lsm_set_self_attr
461 n64 lsm_list_modules sys_lsm_list_modules
+462 n64 setxattrat sys_setxattrat
+463 n64 getxattrat sys_getxattrat
+464 n64 listxattrat sys_listxattrat
+465 n64 removexattrat sys_removexattrat
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index f45c9530ea93..8b5fec66ec18 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -449,3 +449,7 @@
459 o32 lsm_get_self_attr sys_lsm_get_self_attr
460 o32 lsm_set_self_attr sys_lsm_set_self_attr
461 o32 lsm_list_modules sys_lsm_list_modules
+462 o32 setxattrat sys_setxattrat
+463 o32 getxattrat sys_getxattrat
+464 o32 listxattrat sys_listxattrat
+465 o32 removexattrat sys_removexattrat
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index b236a84c4e12..b6ebcaadd460 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -460,3 +460,7 @@
459 common lsm_get_self_attr sys_lsm_get_self_attr
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
+462 common setxattrat sys_setxattrat
+463 common getxattrat sys_getxattrat
+464 common listxattrat sys_listxattrat
+465 common removexattrat sys_removexattrat
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index 17173b82ca21..7e522a720e1a 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -548,3 +548,7 @@
459 common lsm_get_self_attr sys_lsm_get_self_attr
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
+462 common setxattrat sys_setxattrat
+463 common getxattrat sys_getxattrat
+464 common listxattrat sys_listxattrat
+465 common removexattrat sys_removexattrat
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index 095bb86339a7..71afa1eb35fb 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -464,3 +464,7 @@
459 common lsm_get_self_attr sys_lsm_get_self_attr sys_lsm_get_self_attr
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 setxattrat sys_setxattrat sys_setxattrat
+463 common getxattrat sys_getxattrat sys_getxattrat
+464 common listxattrat sys_listxattrat sys_listxattrat
+465 common removexattrat sys_removexattrat sys_removexattrat
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index 86fe269f0220..1fb0ac9f6c58 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -464,3 +464,7 @@
459 common lsm_get_self_attr sys_lsm_get_self_attr
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
+462 common setxattrat sys_setxattrat
+463 common getxattrat sys_getxattrat
+464 common listxattrat sys_listxattrat
+465 common removexattrat sys_removexattrat
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index b23d59313589..bdd90010c8d1 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -507,3 +507,7 @@
459 common lsm_get_self_attr sys_lsm_get_self_attr
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
+462 common setxattrat sys_setxattrat
+463 common getxattrat sys_getxattrat
+464 common listxattrat sys_listxattrat
+465 common removexattrat sys_removexattrat
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 5f8591ce7f25..779dd1a9835d 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -466,3 +466,7 @@
459 i386 lsm_get_self_attr sys_lsm_get_self_attr
460 i386 lsm_set_self_attr sys_lsm_set_self_attr
461 i386 lsm_list_modules sys_lsm_list_modules
+462 i386 setxattrat sys_setxattrat
+463 i386 getxattrat sys_getxattrat
+464 i386 listxattrat sys_listxattrat
+465 i386 removexattrat sys_removexattrat
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 7e8d46f4147f..819c90564f82 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -383,6 +383,10 @@
459 common lsm_get_self_attr sys_lsm_get_self_attr
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
+462 common setxattrat sys_setxattrat
+463 common getxattrat sys_getxattrat
+464 common listxattrat sys_listxattrat
+465 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 dd116598fb25..36bdfe759878 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -432,3 +432,7 @@
459 common lsm_get_self_attr sys_lsm_get_self_attr
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
+462 common setxattrat sys_setxattrat
+463 common getxattrat sys_getxattrat
+464 common listxattrat sys_listxattrat
+465 common removexattrat sys_removexattrat
diff --git a/fs/xattr.c b/fs/xattr.c
index 941aab719da0..d45e83224a7c 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -655,21 +655,28 @@ setxattr(struct mnt_idmap *idmap, struct dentry *d,
return error;
}

-static int path_setxattr(const char __user *pathname,
+static int do_setxattrat(int dfd, const char __user *pathname, unsigned int at_flags,
const char __user *name, const void __user *value,
- size_t size, int flags, unsigned int lookup_flags)
+ size_t size, int xattr_flags)
{
struct path path;
int error;
+ int lookup_flags;

+ if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
+ return -EINVAL;
+
+ lookup_flags = (at_flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
+ if (at_flags & AT_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
retry:
- error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
+ error = user_path_at(dfd, pathname, lookup_flags, &path);
if (error)
return error;
error = mnt_want_write(path.mnt);
if (!error) {
error = setxattr(mnt_idmap(path.mnt), path.dentry, name,
- value, size, flags);
+ value, size, xattr_flags);
mnt_drop_write(path.mnt);
}
path_put(&path);
@@ -680,18 +687,38 @@ static int path_setxattr(const char __user *pathname,
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;
+
+ if (usize > PAGE_SIZE)
+ return -E2BIG;
+ if (usize < sizeof(args))
+ return -EINVAL;
+
+ error = copy_struct_from_user(&args, sizeof(args), uargs, usize);
+ if (error)
+ return error;
+
+ return do_setxattrat(dfd, pathname, at_flags, name, (const void __user *)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 do_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 do_setxattrat(AT_FDCWD, pathname, AT_SYMLINK_NOFOLLOW, name, value, size, flags);
}

SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
@@ -774,14 +801,22 @@ getxattr(struct mnt_idmap *idmap, struct dentry *d,
return error;
}

-static ssize_t path_getxattr(const char __user *pathname,
+static ssize_t do_getxattrat(int dfd, const char __user *pathname, unsigned int at_flags,
const char __user *name, void __user *value,
- size_t size, unsigned int lookup_flags)
+ size_t size)
{
struct path path;
ssize_t error;
+ int lookup_flags;
+
+ if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
+ return -EINVAL;
+
+ lookup_flags = (at_flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
+ if (at_flags & AT_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
retry:
- error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
+ error = user_path_at(dfd, pathname, lookup_flags, &path);
if (error)
return error;
error = getxattr(mnt_idmap(path.mnt), path.dentry, name, value, size);
@@ -793,16 +828,37 @@ static ssize_t path_getxattr(const char __user *pathname,
return error;
}

+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;
+
+ if (usize > PAGE_SIZE)
+ return -E2BIG;
+ if (usize < sizeof(args))
+ return -EINVAL;
+
+ error = copy_struct_from_user(&args, sizeof(args), uargs, usize);
+ if (error)
+ return error;
+
+ if (args.flags != 0)
+ return -EINVAL;
+
+ return do_getxattrat(dfd, pathname, at_flags, name, (void __user *)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 do_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 do_getxattrat(AT_FDCWD, pathname, AT_SYMLINK_NOFOLLOW, name, value, size);
}

SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
@@ -852,13 +908,21 @@ listxattr(struct dentry *d, char __user *list, size_t size)
return error;
}

-static ssize_t path_listxattr(const char __user *pathname, char __user *list,
- size_t size, unsigned int lookup_flags)
+static ssize_t do_listxattrat(int dfd, const char __user *pathname, char __user *list,
+ size_t size, int flags)
{
struct path path;
ssize_t error;
+ int lookup_flags;
+
+ if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
+ return -EINVAL;
+
+ lookup_flags = (flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
+ if (flags & AT_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
retry:
- error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
+ error = user_path_at(dfd, pathname, lookup_flags, &path);
if (error)
return error;
error = listxattr(path.dentry, list, size);
@@ -870,16 +934,22 @@ static ssize_t path_listxattr(const char __user *pathname, char __user *list,
return error;
}

+SYSCALL_DEFINE5(listxattrat, int, dfd, const char __user *, pathname, char __user *, list,
+ size_t, size, int, flags)
+{
+ return do_listxattrat(dfd, pathname, list, size, flags);
+}
+
SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
size_t, size)
{
- return path_listxattr(pathname, list, size, LOOKUP_FOLLOW);
+ return do_listxattrat(AT_FDCWD, pathname, list, size, 0);
}

SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
size_t, size)
{
- return path_listxattr(pathname, list, size, 0);
+ return do_listxattrat(AT_FDCWD, pathname, list, size, AT_SYMLINK_NOFOLLOW);
}

SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
@@ -898,7 +968,7 @@ SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
/*
* Extended attribute REMOVE operations
*/
-static long
+static int
removexattr(struct mnt_idmap *idmap, struct dentry *d,
const char __user *name)
{
@@ -917,13 +987,21 @@ removexattr(struct mnt_idmap *idmap, struct dentry *d,
return vfs_removexattr(idmap, d, kname);
}

-static int path_removexattr(const char __user *pathname,
- const char __user *name, unsigned int lookup_flags)
+static int do_removexattrat(int dfd, const char __user *pathname,
+ const char __user *name, int flags)
{
struct path path;
int error;
+ int lookup_flags;
+
+ if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
+ return -EINVAL;
+
+ lookup_flags = (flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
+ if (flags & AT_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
retry:
- error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
+ error = user_path_at(dfd, pathname, lookup_flags, &path);
if (error)
return error;
error = mnt_want_write(path.mnt);
@@ -939,16 +1017,22 @@ static int path_removexattr(const char __user *pathname,
return error;
}

+SYSCALL_DEFINE4(removexattrat, int, dfd, const char __user *, pathname,
+ const char __user *, name, int, flags)
+{
+ return do_removexattrat(dfd, pathname, name, flags);
+}
+
SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
const char __user *, name)
{
- return path_removexattr(pathname, name, LOOKUP_FOLLOW);
+ return do_removexattrat(AT_FDCWD, pathname, name, 0);
}

SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
const char __user *, name)
{
- return path_removexattr(pathname, name, 0);
+ return do_removexattrat(AT_FDCWD, pathname, name, AT_SYMLINK_NOFOLLOW);
}

SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, 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 e619ac10cd23..e06fffc48535 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -338,23 +338,33 @@ 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, char __user *list,
+ size_t size, int flags);
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,
+ const char __user *name, int flags);
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/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 75f00965ab15..21b275a8dcd6 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -842,8 +842,18 @@ __SYSCALL(__NR_lsm_set_self_attr, sys_lsm_set_self_attr)
#define __NR_lsm_list_modules 461
__SYSCALL(__NR_lsm_list_modules, sys_lsm_list_modules)

+/* fs/xattr.c */
+#define __NR_setxattrat 462
+__SYSCALL(__NR_setxattrat, sys_setxattrat)
+#define __NR_getxattrat 463
+__SYSCALL(__NR_getxattrat, sys_getxattrat)
+#define __NR_listxattrat 464
+__SYSCALL(__NR_listxattrat, sys_listxattrat)
+#define __NR_removexattrat 465
+__SYSCALL(__NR_removexattrat, sys_removexattrat)
+
#undef __NR_syscalls
-#define __NR_syscalls 462
+#define __NR_syscalls 466

/*
* 32 bit systems traditionally used different
diff --git a/include/uapi/linux/xattr.h b/include/uapi/linux/xattr.h
index 9463db2dfa9d..e9ac2acc40c3 100644
--- a/include/uapi/linux/xattr.h
+++ b/include/uapi/linux/xattr.h
@@ -20,6 +20,12 @@

#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 */
--
2.43.0