Confirmed users
2,456
edits
Software Update:MAR: Difference between revisions
m
→SIGNATURE_ENTRY.SignatureAlgorithmID: Fix SHA384 signature size
No edit summary |
m (→SIGNATURE_ENTRY.SignatureAlgorithmID: Fix SHA384 signature size) |
||
| (14 intermediate revisions by 4 users not shown) | |||
| Line 27: | Line 27: | ||
ADDITIONAL_SECTION_ENTRY (Only present if NumAdditionalSections is more than 0) | ADDITIONAL_SECTION_ENTRY (Only present if NumAdditionalSections is more than 0) | ||
4 bytes: BlockSize - (Z) | 4 bytes: BlockSize - (Z) | ||
4 bytes: BlockIdentifier - Used to identify the | 4 bytes: BlockIdentifier - Used to identify the additional section, 1 for a Product Information Block. | ||
(Z-8) bytes: The rest of the block. | (Z-8) bytes: The rest of the block. | ||
| Line 55: | Line 55: | ||
1: RSA-PKCS1-SHA1 (2048 bits / 256 bytes) | 1: RSA-PKCS1-SHA1 (2048 bits / 256 bytes) | ||
2: RSA-PKCS1-SHA384 (4096 bits / 512 bytes) | |||
The updater will only accept the MAR file if at least one of the signatures verify. | The updater will only accept the MAR file if at least one of the signatures verify. | ||
Some versions of the updater may not apply a MAR file unless a valid signature of a particular <tt>SIGNATURE_ENTRY.SignatureAlgorithmID</tt> is included in the MAR file. | Some versions of the updater may not apply a MAR file unless a valid signature of a particular <tt>SIGNATURE_ENTRY.SignatureAlgorithmID</tt> is included in the MAR file. | ||
From Firefox 10-56, only RSA-PKCS1-SHA1 signatures are accepted. [https://bugzilla.mozilla.org/show_bug.cgi?id=1105689 Bug 1105689] adds support for SHA-384 and is slated for Firefox 56. | |||
There is no indicator in the MAR file for which operating system the MAR is for. | There is no indicator in the MAR file for which operating system the MAR is for. | ||
| Line 87: | Line 88: | ||
The product information block identifies the product and channel this MAR file applies to. It also includes the new version number to avoid downgrades. | The product information block identifies the product and channel this MAR file applies to. It also includes the new version number to avoid downgrades. | ||
The product and channel are combined in the MARChannelName field. | |||
PRODUCT INFORMATION BLOCK | PRODUCT INFORMATION BLOCK | ||
4 bytes: | 4 bytes: BlockSize - The size of the product information block. | ||
4 bytes: | 4 bytes: BlockIdentifier - The identifier of the product information block, with a value of 1 | ||
<64 bytes: | <64 bytes: MARChannelName used to identify the product and channel (such as from MAR_CHANNEL_ID) Example: mozilla-central | ||
1 byte: null terminator | 1 byte: null terminator | ||
<32 bytes: ProductVersion string (such as from MOZ_APP_VERSION) Examples: 12.0.1.5371, 12.0a1 | <32 bytes: ProductVersion string (such as from MOZ_APP_VERSION) Examples: 12.0.1.5371, 12.0a1 | ||
1 byte: null terminator | 1 byte: null terminator | ||
* bytes: Optional unused data adding up to BlockSize. | |||
== Source Code == | == Source Code == | ||
| Line 107: | Line 108: | ||
This question was given a fair amount of consideration. Ultimately, we decided to go with a custom file format because using libjar would have required a fair bit of hacking. Writing custom code was a simpler option, and it resulted in less code (mar_read.c is less than 300 lines of code). Moreover, the update system does not need a standard file format. The elements stored in the archive are bzip2 compressed binary diffs, generated using a variation of bsdiff. So, being able to unpack the archive file using standard tools wouldn't be very useful in and of itself. | This question was given a fair amount of consideration. Ultimately, we decided to go with a custom file format because using libjar would have required a fair bit of hacking. Writing custom code was a simpler option, and it resulted in less code (mar_read.c is less than 300 lines of code). Moreover, the update system does not need a standard file format. The elements stored in the archive are bzip2 compressed binary diffs, generated using a variation of bsdiff. So, being able to unpack the archive file using standard tools wouldn't be very useful in and of itself. | ||
== MAR extraction tools == | |||
There’s 2 different python scripts: | |||
* http://hg.mozilla.org/build/tools/file/b77b517eab66/buildfarm/utils/mar.py | |||
* https://github.com/mozilla/build-mar | |||
Note: | |||
* The latter is more recent, but has more dependencies. | |||
* The former works just fine for extracting files | |||
** to use the former: cd tmp_dir; mar.py -x ../foo.mar | |||
** for bzip2'ed files such as b2g mar files: try 'mar.py -x -j fota-flame-update.mar' | |||
** or 'mv update.zip update.zip.bz2; bunzip2 update.zip.bz2' | |||