33 Summary information

In this chapter

33.1Layout [spec] [observed]33.2Properties an installer package sets 33.3The code page trap - keep summary strings ASCII [observed]33.4Worked example: the tutorial's hello.msi

Every package has a stream \x05SummaryInformation (the first character is U+0005; the name is not packed). It is an OLE property set as specified in [MS-OLEPS]; Microsoft Learn ("Summary Information Stream Property Set") says which properties an installer package uses.

33.1 Layout [spec] [observed]#

u16  byte order      FFFE
u16  version         0 (msi.dll writes 0)
u32  OS field        msi.dll writes 0x00020206
16   CLSID           zero
u32  section count   1
16   FMTID           F29F85E0-4FF9-1068-AB91-08002B27B3D9, stored E0 85 9F F2 F9 4F 68 10 AB 91 08 00 2B 27 B3 D9
u32  section offset  48

section:
u32  section size
u32  property count
count x (u32 property id, u32 offset from the section start)
values, each padded to a multiple of 4 bytes:
  VT_I2 (2)        u32 type, i16 value, 2 bytes padding
  VT_I4 (3)        u32 type, i32 value
  VT_LPSTR (30)    u32 type, u32 byte count including the NUL, bytes, NUL, padding
  VT_FILETIME (64) u32 type, u64 100-ns intervals since 1601-01-01 UTC

33.2 Properties an installer package sets#

Id	Name	Type	Value
2	Title	LPSTR	e.g. `Installation Database`
3	Subject	LPSTR	product name
4	Author	LPSTR	manufacturer
5	Keywords	LPSTR	e.g. `Installer`
7	Template	LPSTR	`<platform>;<language id>`: `x64;1033`, `Arm64;1042`, `Intel;1033`
9	Revision Number	LPSTR	the package code: a GUID, new for every different package file
12, 13	Create / Last Save time	FILETIME	optional
14	Page Count	I4	minimum installer version: 200 for x64 and x86, 500 for Arm64
15	Word Count	I4	bit 1 = files are compressed (in cabinets); 2 for a normal package
18	Creating Application	LPSTR	any

33.3 The code page trap - keep summary strings ASCII [observed]#

Property 1 (CodePage, VT_I2) says how the LPSTR bytes are encoded. On Windows 11 25H2:

65001: msi.dll writes the strings correctly as UTF-8, but reads the code page back as the signed value -535, fails to convert every string (the installation log says "Failed to retrieve # 9 summary info property. GetLastError returned 87, the code page is -535") and refuses the package with error 1620.
1200 (UTF-16): refused the same way (log: "... the code page is 1200"), even with complete UTF-16 strings and byte counts that follow [MS-OLEPS].
No code page property and ASCII strings: installs.

So: leave property 1 out and write every summary string in ASCII. Localized product names belong in the Property table (ProductName), which uses the database code page - and 65001 works there (see The MSI database inside the compound file).

33.4 Worked example: the tutorial's hello.msi#

The tutorial's first package: the stream is 336 bytes. Its header:

Offset	Bytes	Field	Value
`0x00`	`fe ff`	byte order	0xFFFE
`0x04`	`06 02 02 00`	OS	0x00020206
`0x18`	`01 00 00 00`	section count	1
`0x1C`	`e0 85 9f f2 ...`	FMTID	`F29F85E0-...`
`0x2C`	`30 00 00 00`	section offset	48
`0x30`	`20 01 00 00`	section size	288
`0x34`	`09 00 00 00`	property count	9

Then 9 pairs of (property id, offset), and the values:

Property	Offset	Type	Raw bytes	Value
2	`0x80`	VT_LPSTR	`1e 00 00 00 16 00 00 00 49 6e 73 74 61 6c 6c 61 ...`	`Installation Database`
3	`0xA0`	VT_LPSTR	`1e 00 00 00 06 00 00 00 48 65 6c 6c 6f 00`	`Hello`
4	`0xB0`	VT_LPSTR	`1e 00 00 00 11 00 00 00 45 78 61 6d 70 6c 65 20 ...`	`Example Software`
5	`0xCC`	VT_LPSTR	`1e 00 00 00 0a 00 00 00 49 6e 73 74 61 6c 6c 65 ...`	`Installer`
7	`0xE0`	VT_LPSTR	`1e 00 00 00 09 00 00 00 78 36 34 3b 31 30 33 33 ...`	`x64;1033`
9	`0xF4`	VT_LPSTR	`1e 00 00 00 27 00 00 00 7b 38 44 37 41 37 36 38 ...`	`{8D7A7687-4BF3-8D46-8B4C-CA8BB13937CF}`
14	`0x124`	VT_I4	`03 00 00 00 c8 00 00 00`	200
15	`0x12C`	VT_I4	`03 00 00 00 02 00 00 00`	2
18	`0x134`	VT_LPSTR	`1e 00 00 00 11 00 00 00 72 75 62 72 61 70 61 63 ...`	`rubrapack 0.39.0`

A string value is its type (30), its byte count including the NUL, the bytes, the NUL, and padding to a multiple of 4. Property 9, the package code, is derived from the content under --reproducible; without it every build gets a new one.

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