From 2ba6198851dc1e293295d7cadf8c0ae456b68beb Mon Sep 17 00:00:00 2001 From: Dean Deng Date: Tue, 21 Jan 2020 12:41:50 -0800 Subject: Add syscalls for lgetxattr, fgetxattr, lsetxattr, and fsetxattr. Note that these simply will use the same logic as getxattr and setxattr, which is not yet implemented for most filesystems. PiperOrigin-RevId: 290800960 --- pkg/sentry/syscalls/linux/linux64_amd64.go | 8 +- pkg/sentry/syscalls/linux/linux64_arm64.go | 8 +- pkg/sentry/syscalls/linux/sys_xattr.go | 136 +++++++++++++++++++++-------- 3 files changed, 109 insertions(+), 43 deletions(-) (limited to 'pkg') diff --git a/pkg/sentry/syscalls/linux/linux64_amd64.go b/pkg/sentry/syscalls/linux/linux64_amd64.go index 6b2920900..c76771a54 100644 --- a/pkg/sentry/syscalls/linux/linux64_amd64.go +++ b/pkg/sentry/syscalls/linux/linux64_amd64.go @@ -229,11 +229,11 @@ var AMD64 = &kernel.SyscallTable{ 186: syscalls.Supported("gettid", Gettid), 187: syscalls.Supported("readahead", Readahead), 188: syscalls.PartiallySupported("setxattr", SetXattr, "Only supported for tmpfs.", nil), - 189: syscalls.Error("lsetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil), - 190: syscalls.Error("fsetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil), + 189: syscalls.PartiallySupported("lsetxattr", LSetXattr, "Only supported for tmpfs.", nil), + 190: syscalls.PartiallySupported("fsetxattr", FSetXattr, "Only supported for tmpfs.", nil), 191: syscalls.PartiallySupported("getxattr", GetXattr, "Only supported for tmpfs.", nil), - 192: syscalls.ErrorWithEvent("lgetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil), - 193: syscalls.ErrorWithEvent("fgetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil), + 192: syscalls.PartiallySupported("lgetxattr", LGetXattr, "Only supported for tmpfs.", nil), + 193: syscalls.PartiallySupported("fgetxattr", FGetXattr, "Only supported for tmpfs.", nil), 194: syscalls.ErrorWithEvent("listxattr", syserror.ENOTSUP, "Requires filesystem support.", nil), 195: syscalls.ErrorWithEvent("llistxattr", syserror.ENOTSUP, "Requires filesystem support.", nil), 196: syscalls.ErrorWithEvent("flistxattr", syserror.ENOTSUP, "Requires filesystem support.", nil), diff --git a/pkg/sentry/syscalls/linux/linux64_arm64.go b/pkg/sentry/syscalls/linux/linux64_arm64.go index c9629f6f3..d3587fda6 100644 --- a/pkg/sentry/syscalls/linux/linux64_arm64.go +++ b/pkg/sentry/syscalls/linux/linux64_arm64.go @@ -42,11 +42,11 @@ var ARM64 = &kernel.SyscallTable{ 3: syscalls.PartiallySupported("io_cancel", IoCancel, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}), 4: syscalls.PartiallySupported("io_getevents", IoGetevents, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}), 5: syscalls.PartiallySupported("setxattr", SetXattr, "Only supported for tmpfs.", nil), - 6: syscalls.Error("lsetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil), - 7: syscalls.Error("fsetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil), + 6: syscalls.PartiallySupported("lsetxattr", LSetXattr, "Only supported for tmpfs.", nil), + 7: syscalls.PartiallySupported("fsetxattr", FSetXattr, "Only supported for tmpfs.", nil), 8: syscalls.PartiallySupported("getxattr", GetXattr, "Only supported for tmpfs.", nil), - 9: syscalls.ErrorWithEvent("lgetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil), - 10: syscalls.ErrorWithEvent("fgetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil), + 9: syscalls.PartiallySupported("lgetxattr", LGetXattr, "Only supported for tmpfs.", nil), + 10: syscalls.PartiallySupported("fgetxattr", FGetXattr, "Only supported for tmpfs.", nil), 11: syscalls.ErrorWithEvent("listxattr", syserror.ENOTSUP, "Requires filesystem support.", nil), 12: syscalls.ErrorWithEvent("llistxattr", syserror.ENOTSUP, "Requires filesystem support.", nil), 13: syscalls.ErrorWithEvent("flistxattr", syserror.ENOTSUP, "Requires filesystem support.", nil), diff --git a/pkg/sentry/syscalls/linux/sys_xattr.go b/pkg/sentry/syscalls/linux/sys_xattr.go index 23d20da6f..e35c077d6 100644 --- a/pkg/sentry/syscalls/linux/sys_xattr.go +++ b/pkg/sentry/syscalls/linux/sys_xattr.go @@ -27,6 +27,40 @@ import ( // GetXattr implements linux syscall getxattr(2). func GetXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + return getXattrFromPath(t, args, true) +} + +// LGetXattr implements linux syscall lgetxattr(2). +func LGetXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + return getXattrFromPath(t, args, false) +} + +// FGetXattr implements linux syscall fgetxattr(2). +func FGetXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + fd := args[0].Int() + nameAddr := args[1].Pointer() + valueAddr := args[2].Pointer() + size := uint64(args[3].SizeT()) + + // TODO(b/113957122): Return EBADF if the fd was opened with O_PATH. + f := t.GetFile(fd) + if f == nil { + return 0, nil, syserror.EBADF + } + defer f.DecRef() + + n, value, err := getXattr(t, f.Dirent, nameAddr, size) + if err != nil { + return 0, nil, err + } + + if _, err := t.CopyOutBytes(valueAddr, []byte(value)); err != nil { + return 0, nil, err + } + return uintptr(n), nil, nil +} + +func getXattrFromPath(t *kernel.Task, args arch.SyscallArguments, resolveSymlink bool) (uintptr, *kernel.SyscallControl, error) { pathAddr := args[0].Pointer() nameAddr := args[1].Pointer() valueAddr := args[2].Pointer() @@ -38,29 +72,17 @@ func GetXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc } valueLen := 0 - err = fileOpOn(t, linux.AT_FDCWD, path, true /* resolve */, func(root *fs.Dirent, d *fs.Dirent, _ uint) error { - // If getxattr(2) is called with size 0, the size of the value will be - // returned successfully even if it is nonzero. In that case, we need to - // retrieve the entire attribute value so we can return the correct size. - requestedSize := size - if size == 0 || size > linux.XATTR_SIZE_MAX { - requestedSize = linux.XATTR_SIZE_MAX + err = fileOpOn(t, linux.AT_FDCWD, path, resolveSymlink, func(root *fs.Dirent, d *fs.Dirent, _ uint) error { + if dirPath && !fs.IsDir(d.Inode.StableAttr) { + return syserror.ENOTDIR } - value, err := getXattr(t, d, dirPath, nameAddr, uint64(requestedSize)) + n, value, err := getXattr(t, d, nameAddr, size) + valueLen = n if err != nil { return err } - valueLen = len(value) - if uint64(valueLen) > requestedSize { - return syserror.ERANGE - } - - // Skip copying out the attribute value if size is 0. - if size == 0 { - return nil - } _, err = t.CopyOutBytes(valueAddr, []byte(value)) return err }) @@ -71,29 +93,73 @@ func GetXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc } // getXattr implements getxattr(2) from the given *fs.Dirent. -func getXattr(t *kernel.Task, d *fs.Dirent, dirPath bool, nameAddr usermem.Addr, size uint64) (string, error) { - if dirPath && !fs.IsDir(d.Inode.StableAttr) { - return "", syserror.ENOTDIR - } - +func getXattr(t *kernel.Task, d *fs.Dirent, nameAddr usermem.Addr, size uint64) (int, string, error) { if err := checkXattrPermissions(t, d.Inode, fs.PermMask{Read: true}); err != nil { - return "", err + return 0, "", err } name, err := copyInXattrName(t, nameAddr) if err != nil { - return "", err + return 0, "", err } if !strings.HasPrefix(name, linux.XATTR_USER_PREFIX) { - return "", syserror.EOPNOTSUPP + return 0, "", syserror.EOPNOTSUPP } - return d.Inode.GetXattr(t, name, size) + // If getxattr(2) is called with size 0, the size of the value will be + // returned successfully even if it is nonzero. In that case, we need to + // retrieve the entire attribute value so we can return the correct size. + requestedSize := size + if size == 0 || size > linux.XATTR_SIZE_MAX { + requestedSize = linux.XATTR_SIZE_MAX + } + + value, err := d.Inode.GetXattr(t, name, requestedSize) + if err != nil { + return 0, "", err + } + n := len(value) + if uint64(n) > requestedSize { + return 0, "", syserror.ERANGE + } + + // Don't copy out the attribute value if size is 0. + if size == 0 { + return n, "", nil + } + return n, value, nil } // SetXattr implements linux syscall setxattr(2). func SetXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + return setXattrFromPath(t, args, true) +} + +// LSetXattr implements linux syscall lsetxattr(2). +func LSetXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + return setXattrFromPath(t, args, false) +} + +// FSetXattr implements linux syscall fsetxattr(2). +func FSetXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + fd := args[0].Int() + nameAddr := args[1].Pointer() + valueAddr := args[2].Pointer() + size := uint64(args[3].SizeT()) + flags := args[4].Uint() + + // TODO(b/113957122): Return EBADF if the fd was opened with O_PATH. + f := t.GetFile(fd) + if f == nil { + return 0, nil, syserror.EBADF + } + defer f.DecRef() + + return 0, nil, setXattr(t, f.Dirent, nameAddr, valueAddr, uint64(size), flags) +} + +func setXattrFromPath(t *kernel.Task, args arch.SyscallArguments, resolveSymlink bool) (uintptr, *kernel.SyscallControl, error) { pathAddr := args[0].Pointer() nameAddr := args[1].Pointer() valueAddr := args[2].Pointer() @@ -105,19 +171,19 @@ func SetXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc return 0, nil, err } - if flags&^(linux.XATTR_CREATE|linux.XATTR_REPLACE) != 0 { - return 0, nil, syserror.EINVAL - } + return 0, nil, fileOpOn(t, linux.AT_FDCWD, path, resolveSymlink, func(root *fs.Dirent, d *fs.Dirent, _ uint) error { + if dirPath && !fs.IsDir(d.Inode.StableAttr) { + return syserror.ENOTDIR + } - return 0, nil, fileOpOn(t, linux.AT_FDCWD, path, true /* resolve */, func(root *fs.Dirent, d *fs.Dirent, _ uint) error { - return setXattr(t, d, dirPath, nameAddr, valueAddr, uint64(size), flags) + return setXattr(t, d, nameAddr, valueAddr, uint64(size), flags) }) } // setXattr implements setxattr(2) from the given *fs.Dirent. -func setXattr(t *kernel.Task, d *fs.Dirent, dirPath bool, nameAddr, valueAddr usermem.Addr, size uint64, flags uint32) error { - if dirPath && !fs.IsDir(d.Inode.StableAttr) { - return syserror.ENOTDIR +func setXattr(t *kernel.Task, d *fs.Dirent, nameAddr, valueAddr usermem.Addr, size uint64, flags uint32) error { + if flags&^(linux.XATTR_CREATE|linux.XATTR_REPLACE) != 0 { + return syserror.EINVAL } if err := checkXattrPermissions(t, d.Inode, fs.PermMask{Write: true}); err != nil { @@ -133,7 +199,7 @@ func setXattr(t *kernel.Task, d *fs.Dirent, dirPath bool, nameAddr, valueAddr us return syserror.E2BIG } buf := make([]byte, size) - if _, err = t.CopyInBytes(valueAddr, buf); err != nil { + if _, err := t.CopyInBytes(valueAddr, buf); err != nil { return err } value := string(buf) -- cgit v1.2.3