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From: Al Viro <[email protected]>
To: [email protected]
Cc: "Christian Brauner" <[email protected]>,
	[email protected],
	"Christian Göttsche" <[email protected]>
Subject: [PATCH v2 12/13] fs/xattr: add *at family syscalls
Date: Sat,  2 Nov 2024 07:31:48 +0000	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

From: Christian Göttsche <[email protected]>

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]>
---
 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                                  | 245 +++++++++++++-------
 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, 260 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 b76911b23293..deb336b821c9 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -676,69 +676,90 @@ 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_maybe_null(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);
 }
 
 /*
@@ -804,11 +825,10 @@ 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,
@@ -816,44 +836,72 @@ 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_maybe_null(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);
 }
 
 /*
@@ -918,32 +966,50 @@ 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_maybe_null(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);
 }
 
 /*
@@ -996,44 +1062,53 @@ 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_maybe_null(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


  parent reply	other threads:[~2024-11-02  7:31 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-02  1:10 [RFC][PATCHES] xattr stuff and interactions with io_uring Al Viro
2024-10-02  1:22 ` [PATCH 1/9] xattr: switch to CLASS(fd) Al Viro
2024-10-02  1:22   ` [PATCH 2/9] fs: rename struct xattr_ctx to kernel_xattr_ctx Al Viro
2024-10-02  5:56     ` Christian Brauner
2024-10-02  1:22   ` [PATCH 3/9] io_[gs]etxattr_prep(): just use getname() Al Viro
2024-10-02  5:57     ` Christian Brauner
2024-10-02  1:22   ` [PATCH 4/9] new helper: import_xattr_name() Al Viro
2024-10-02  5:57     ` Christian Brauner
2024-10-02  1:22   ` [PATCH 5/9] replace do_setxattr() with saner helpers Al Viro
2024-10-02  1:34     ` Jens Axboe
2024-10-02  2:08       ` Al Viro
2024-10-02 18:00         ` Jens Axboe
2024-10-02 21:19           ` Al Viro
2024-10-02 22:55             ` Jens Axboe
2024-10-06  5:28               ` Al Viro
2024-10-07 18:09                 ` Jens Axboe
2024-10-07 18:20                   ` Jens Axboe
2024-10-07 21:20                     ` Al Viro
2024-10-07 22:29                       ` Jens Axboe
2024-10-07 23:58                         ` Al Viro
2024-10-08  1:58                           ` Jens Axboe
2024-10-08  4:08                             ` Al Viro
2024-10-02  1:22   ` [PATCH 6/9] replace do_getxattr() " Al Viro
2024-10-02  5:59     ` Christian Brauner
2024-10-02  1:22   ` [PATCH 7/9] new helpers: file_listxattr(), filename_listxattr() Al Viro
2024-10-02  6:00     ` Christian Brauner
2024-10-02  1:22   ` [PATCH 8/9] new helpers: file_removexattr(), filename_removexattr() Al Viro
2024-10-02  6:01     ` Christian Brauner
2024-10-02  1:22   ` [PATCH 9/9] fs/xattr: add *at family syscalls Al Viro
2024-10-02  6:03     ` Christian Brauner
2024-10-02  5:56   ` [PATCH 1/9] xattr: switch to CLASS(fd) Christian Brauner
2024-11-02  7:28 ` [RFC][PATCHES v2] xattr stuff and interactions with io_uring Al Viro
2024-11-02  7:31   ` [PATCH v2 01/13] teach filename_lookup() to treat NULL filename as "" Al Viro
2024-11-02  7:31     ` [PATCH v2 02/13] getname_maybe_null() - the third variant of pathname copy-in Al Viro
2024-11-02  7:31     ` [PATCH v2 03/13] io_uring: IORING_OP_F[GS]ETXATTR is fine with REQ_F_FIXED_FILE Al Viro
2024-11-02  7:31     ` [PATCH v2 04/13] io_[gs]etxattr_prep(): just use getname() Al Viro
2024-11-02  7:31     ` [PATCH v2 05/13] xattr: switch to CLASS(fd) Al Viro
2024-11-02  7:31     ` [PATCH v2 06/13] fs: rename struct xattr_ctx to kernel_xattr_ctx Al Viro
2024-11-02  7:31     ` [PATCH v2 07/13] new helper: import_xattr_name() Al Viro
2024-11-02  7:31     ` [PATCH v2 08/13] replace do_setxattr() with saner helpers Al Viro
2024-11-02  7:31     ` [PATCH v2 09/13] replace do_getxattr() " Al Viro
2024-11-02  7:31     ` [PATCH v2 10/13] new helpers: file_listxattr(), filename_listxattr() Al Viro
2024-11-02  7:31     ` [PATCH v2 11/13] new helpers: file_removexattr(), filename_removexattr() Al Viro
2024-11-02  7:31     ` Al Viro [this message]
2024-11-02  7:31     ` [PATCH v2 13/13] xattr: remove redundant check on variable err Al Viro

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