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The Mach-O reader validated segment and section file offsets by checking that they were relative to the same base, insisting that a section’s file offset be the same distance from a segment’s file offset as the section’s preferred load address was from the segment’s preferred load address. Notably, these file offsets already could not be validated against the Mach-O image’s start because in the dyld shared cache, for all segments other than __TEXT, these offsets were relative to the dyld shared cache’s start. In 10.12dp1 16A201w, file offsets for sections in the __TEXT segment are also relative to the dyld shared cache’s start, but the file offset for the __TEXT segment itself is relative to the Mach-O image’s start. Being relative to different positions breaks Crashpad’s sanity check of the module data. https://openradar.appspot.com/26864860 is filed for the use of distinct bases in what should be related file offset fields. While it would be possible with a bit of work to identify modules within the dyld shared cache and adjust expectations accordingly, in reality, these file offset values were only used to verify that the Mach-O module. In addition, the file offsets stored within the Mach-O file for sections are 32-bit quantities, even in 64-bit images. It is possible to create a large image whose section offset values have overflowed, and in these cases, the offset value verification would also fail. For these reasons, all file offset value validation is removed from the Mach-O image reader. BUG=crashpad:118, crashpad:120 Change-Id: I9c4bcc5fd0aeceef3bc8a43e5a8651735852d87b Reviewed-on: https://chromium-review.googlesource.com/353631 Reviewed-by: Robert Sesek <rsesek@chromium.org>