Don't attempt to read data if the note isn't in an allocated segment.
See investigation starting at
https://bugs.chromium.org/p/crashpad/issues/detail?id=220#c27 for
details.
Bug: crashpad:220, crashpad:30, crashpad:196
Change-Id: I60eaacb83ad00ef33bde9079d25cc23a59bdf2c8
Reviewed-on: https://chromium-review.googlesource.com/941507
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Commit-Queue: Scott Graham <scottmg@chromium.org>
Without the section headers for the symbol table, there's no direct way
to calculate the number of entries in the table.
DT_HASH and DT_GNU_HASH are auxiliary tables that are designed to make
symbol lookup faster. DT_HASH is the original and is theoretically
mandatory. DT_GNU_HASH is the new-and-improved, but is more complex.
In practice, however, an Android build (at least vs. API 16) has only
DT_HASH, and not DT_GNU_HASH, and a Fuchsia build has only DT_GNU_HASH
but not DT_HASH. So, both are tried.
This change does not actually use the data in these tables to improve
the speed of symbol lookup, but instead only uses them to correctly
terminate the linear search.
DT_HASH contains the total number of symbols in the symbol table fairly
directly because there is an entry for each symbol table entry in the
hash table, so the number is the same.
DT_GNU_HASH regrettably does not. Instead, it's necessary to walk the
buckets and chain structure to find the largest entry.
DT_GNU_HASH doesn't appear in any "real" documentation that I'm aware
of, other than the binutils code (at least as far as I know). Some
more-and-less-useful references:
- https://flapenguin.me/2017/04/24/elf-lookup-dt-hash/
- https://flapenguin.me/2017/05/10/elf-lookup-dt-gnu-hash/
- http://deroko.phearless.org/dt_gnu_hash.txt
- https://sourceware.org/ml/binutils/2006-10/msg00377.html
Change-Id: I7cfc4372f29efc37446f0931d22a1f790e44076f
Bug: crashpad:213, crashpad:196
Reviewed-on: https://chromium-review.googlesource.com/876879
Commit-Queue: Scott Graham <scottmg@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
(Still need to avoid fork()-dependence for the non-self tests.)
Bug: crashpad:196
Change-Id: Ib34fe33c7ec295881c1f555995072d9ff742647f
Reviewed-on: https://chromium-review.googlesource.com/876650
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Scott Graham <scottmg@chromium.org>
A step towards making these files usable by non-Linux systems.
Bug: crashpad:196
Change-Id: I2497fd7e3bcb5390ae1e6ae22902ab6f56b59dff
Reviewed-on: https://chromium-review.googlesource.com/685405
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Commit-Queue: Dave Bort <dbort@google.com>
A step towards making these files usable by non-Linux systems.
Bug: crashpad:196
Change-Id: I1dc4304b1376a3a5e45228cf40b23f0367d3efa8
Reviewed-on: https://chromium-review.googlesource.com/685404
Commit-Queue: Dave Bort <dbort@google.com>
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
