[RFC PATCH v2] fs/xattr: add *at family syscalls
From: Christian Göttsche
Date: Thu May 11 2023 - 11:08:31 EST
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.
Add XATTR flags to the private namespace of AT_* flags.
Use the do_{name}at() pattern from fs/open.c.
Use a single flag parameter for extended attribute flags (currently
XATTR_CREATE and XATTR_REPLACE) and *at() flags to not exceed six
syscall arguments in setxattrat().
Previous approach ("f*xattr: allow O_PATH descriptors"): https://lore.kernel.org/all/20220607153139.35588-1-cgzones@xxxxxxxxxxxxxx/
v1 discussion: https://lore.kernel.org/all/20220830152858.14866-2-cgzones@xxxxxxxxxxxxxx/
Signed-off-by: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
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
---
v2:
- squash syscall introduction and wire up commits
- add AT_XATTR_CREATE and AT_XATTR_REPLACE constants
---
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/ia64/kernel/syscalls/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 | 107 ++++++++++++++++----
include/asm-generic/audit_change_attr.h | 6 ++
include/linux/syscalls.h | 8 ++
include/uapi/asm-generic/unistd.h | 12 ++-
include/uapi/linux/fcntl.h | 2 +
23 files changed, 185 insertions(+), 24 deletions(-)
diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 8ebacf37a8cf..1dc58a5dc730 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -490,3 +490,7 @@
558 common process_mrelease sys_process_mrelease
559 common futex_waitv sys_futex_waitv
560 common set_mempolicy_home_node sys_ni_syscall
+561 common setxattrat sys_setxattrat
+562 common getxattrat sys_getxattrat
+563 common listxattrat sys_listxattrat
+564 common removexattrat sys_removexattrat
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index ac964612d8b0..f0e9d9d487f0 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -464,3 +464,7 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common setxattrat sys_setxattrat
+452 common getxattrat sys_getxattrat
+453 common listxattrat sys_listxattrat
+454 common removexattrat sys_removexattrat
diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
index 037feba03a51..63a8a9c4abc1 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 451
+#define __NR_compat_syscalls 455
#endif
#define __ARCH_WANT_SYS_CLONE
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index 604a2053d006..cd6ac63376d1 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -907,6 +907,14 @@ __SYSCALL(__NR_process_mrelease, sys_process_mrelease)
__SYSCALL(__NR_futex_waitv, sys_futex_waitv)
#define __NR_set_mempolicy_home_node 450
__SYSCALL(__NR_set_mempolicy_home_node, sys_set_mempolicy_home_node)
+#define __NR_setxattrat 451
+__SYSCALL(__NR_setxattrat, sys_setxattrat)
+#define __NR_getxattrat 452
+__SYSCALL(__NR_getxattrat, sys_getxattrat)
+#define __NR_listxattrat 453
+__SYSCALL(__NR_listxattrat, sys_listxattrat)
+#define __NR_removexattrat 454
+__SYSCALL(__NR_removexattrat, sys_removexattrat)
/*
* Please add new compat syscalls above this comment and update
diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl
index 72c929d9902b..fe9aea54222c 100644
--- a/arch/ia64/kernel/syscalls/syscall.tbl
+++ b/arch/ia64/kernel/syscalls/syscall.tbl
@@ -371,3 +371,7 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common setxattrat sys_setxattrat
+452 common getxattrat sys_getxattrat
+453 common listxattrat sys_listxattrat
+454 common removexattrat sys_removexattrat
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index b1f3940bc298..0847efdee734 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -450,3 +450,7 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common setxattrat sys_setxattrat
+452 common getxattrat sys_getxattrat
+453 common listxattrat sys_listxattrat
+454 common removexattrat sys_removexattrat
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index 820145e47350..7f619bbc718d 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -456,3 +456,7 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common setxattrat sys_setxattrat
+452 common getxattrat sys_getxattrat
+453 common listxattrat sys_listxattrat
+454 common removexattrat sys_removexattrat
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index 253ff994ed2e..5e4206c0aede 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -389,3 +389,7 @@
448 n32 process_mrelease sys_process_mrelease
449 n32 futex_waitv sys_futex_waitv
450 n32 set_mempolicy_home_node sys_set_mempolicy_home_node
+451 n32 setxattrat sys_setxattrat
+452 n32 getxattrat sys_getxattrat
+453 n32 listxattrat sys_listxattrat
+454 n32 removexattrat sys_removexattrat
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index 3f1886ad9d80..df0f053e76cd 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -365,3 +365,7 @@
448 n64 process_mrelease sys_process_mrelease
449 n64 futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 n64 setxattrat sys_setxattrat
+452 n64 getxattrat sys_getxattrat
+453 n64 listxattrat sys_listxattrat
+454 n64 removexattrat sys_removexattrat
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 8f243e35a7b2..09ec31ad475f 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -438,3 +438,7 @@
448 o32 process_mrelease sys_process_mrelease
449 o32 futex_waitv sys_futex_waitv
450 o32 set_mempolicy_home_node sys_set_mempolicy_home_node
+451 o32 setxattrat sys_setxattrat
+452 o32 getxattrat sys_getxattrat
+453 o32 listxattrat sys_listxattrat
+454 o32 removexattrat sys_removexattrat
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index 0e42fceb2d5e..0123f895a674 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -448,3 +448,7 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common setxattrat sys_setxattrat
+452 common getxattrat sys_getxattrat
+453 common listxattrat sys_listxattrat
+454 common removexattrat sys_removexattrat
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index a0be127475b1..06fd4153f0d1 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -537,3 +537,7 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 nospu set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common setxattrat sys_setxattrat
+452 common getxattrat sys_getxattrat
+453 common listxattrat sys_listxattrat
+454 common removexattrat sys_removexattrat
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index b68f47541169..9babd831fe1e 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -453,3 +453,7 @@
448 common process_mrelease sys_process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common setxattrat sys_setxattrat sys_setxattrat
+452 common getxattrat sys_getxattrat sys_getxattrat
+453 common listxattrat sys_listxattrat sys_listxattrat
+454 common removexattrat sys_removexattrat sys_removexattrat
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index 2de85c977f54..d4daa8afe45c 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -453,3 +453,7 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common setxattrat sys_setxattrat
+452 common getxattrat sys_getxattrat
+453 common listxattrat sys_listxattrat
+454 common removexattrat sys_removexattrat
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index 4398cc6fb68d..510d5175f80a 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -496,3 +496,7 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common setxattrat sys_setxattrat
+452 common getxattrat sys_getxattrat
+453 common listxattrat sys_listxattrat
+454 common removexattrat sys_removexattrat
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 320480a8db4f..8488cc157fe0 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -455,3 +455,7 @@
448 i386 process_mrelease sys_process_mrelease
449 i386 futex_waitv sys_futex_waitv
450 i386 set_mempolicy_home_node sys_set_mempolicy_home_node
+451 i386 setxattrat sys_setxattrat
+452 i386 getxattrat sys_getxattrat
+453 i386 listxattrat sys_listxattrat
+454 i386 removexattrat sys_removexattrat
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index c84d12608cd2..f45d723d5a30 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -372,6 +372,10 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common setxattrat sys_setxattrat
+452 common getxattrat sys_getxattrat
+453 common listxattrat sys_listxattrat
+454 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 52c94ab5c205..dbafe441a83f 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -421,3 +421,7 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common setxattrat sys_setxattrat
+452 common getxattrat sys_getxattrat
+453 common listxattrat sys_listxattrat
+454 common removexattrat sys_removexattrat
diff --git a/fs/xattr.c b/fs/xattr.c
index fcf67d80d7f9..a57ce39483d7 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -656,21 +656,34 @@ 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,
const char __user *name, const void __user *value,
- size_t size, int flags, unsigned int lookup_flags)
+ size_t size, int flags)
{
struct path path;
int error;
+ int lookup_flags;
+ /* AT_ and XATTR_ flags must not overlap. */
+ BUILD_BUG_ON(XATTR_CREATE != AT_XATTR_CREATE);
+ BUILD_BUG_ON(XATTR_REPLACE != AT_XATTR_REPLACE);
+ #define AT_XATTR__FLAGS (AT_XATTR_CREATE | AT_XATTR_REPLACE)
+ BUILD_BUG_ON(((AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH) & AT_XATTR__FLAGS) != 0);
+
+ if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH | AT_XATTR__FLAGS)) != 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);
if (!error) {
error = setxattr(mnt_idmap(path.mnt), path.dentry, name,
- value, size, flags);
+ value, size, flags & AT_XATTR__FLAGS);
mnt_drop_write(path.mnt);
}
path_put(&path);
@@ -681,18 +694,25 @@ static int path_setxattr(const char __user *pathname,
return error;
}
+SYSCALL_DEFINE6(setxattrat, int, dfd, const char __user *, pathname,
+ const char __user *, name, const void __user *, value,
+ size_t, size, int, flags)
+{
+ return do_setxattrat(dfd, pathname, name, value, size, 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, 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, name, value, size, flags | AT_SYMLINK_NOFOLLOW);
}
SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
@@ -775,14 +795,22 @@ 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,
const char __user *name, void __user *value,
- size_t size, unsigned int lookup_flags)
+ 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 = getxattr(mnt_idmap(path.mnt), path.dentry, name, value, size);
@@ -794,16 +822,23 @@ static ssize_t path_getxattr(const char __user *pathname,
return error;
}
+SYSCALL_DEFINE6(getxattrat, int, dfd, const char __user *, pathname,
+ const char __user *, name, void __user *, value, size_t, size,
+ int, flags)
+{
+ return do_getxattrat(dfd, pathname, name, value, size, flags);
+}
+
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, name, value, size, 0);
}
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, name, value, size, AT_SYMLINK_NOFOLLOW);
}
SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
@@ -853,13 +888,21 @@ 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);
@@ -871,16 +914,22 @@ 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)
@@ -899,7 +948,7 @@ 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)
{
@@ -918,13 +967,21 @@ 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);
@@ -940,16 +997,22 @@ 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 33a0ee3bcb2e..0612661c9eca 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -350,23 +350,31 @@ asmlinkage long sys_io_uring_register(unsigned int fd, unsigned int op,
/* fs/xattr.c */
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, const char __user *name,
+ const void __user *value, size_t size, int flags);
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, const char __user *name,
+ void __user *value, size_t size, int flags);
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 45fa180cc56a..4fcc71612b7a 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -886,8 +886,18 @@ __SYSCALL(__NR_futex_waitv, sys_futex_waitv)
#define __NR_set_mempolicy_home_node 450
__SYSCALL(__NR_set_mempolicy_home_node, sys_set_mempolicy_home_node)
+/* fs/xattr.c */
+#define __NR_setxattrat 451
+__SYSCALL(__NR_setxattrat, sys_setxattrat)
+#define __NR_getxattrat 452
+__SYSCALL(__NR_getxattrat, sys_getxattrat)
+#define __NR_listxattrat 453
+__SYSCALL(__NR_listxattrat, sys_listxattrat)
+#define __NR_removexattrat 454
+__SYSCALL(__NR_removexattrat, sys_removexattrat)
+
#undef __NR_syscalls
-#define __NR_syscalls 451
+#define __NR_syscalls 455
/*
* 32 bit systems traditionally used different
diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h
index e8c07da58c9f..b456547c8460 100644
--- a/include/uapi/linux/fcntl.h
+++ b/include/uapi/linux/fcntl.h
@@ -96,6 +96,8 @@
#define AT_FDCWD -100 /* Special value used to indicate
openat should use the current
working directory. */
+#define AT_XATTR_CREATE 0x1 /* setxattrat(2): set value, fail if attr already exists */
+#define AT_XATTR_REPLACE 0x2 /* setxattrat(2): set value, fail if attr does not exist */
#define AT_SYMLINK_NOFOLLOW 0x100 /* Do not follow symbolic links. */
#define AT_EACCESS 0x200 /* Test access permitted for
effective IDs, not real IDs. */
--
2.40.1