SELinux blocks the handler from collecting these values on Android M.
They should eventually be collected via the broker.
Change-Id: Iad47759b2ebf23148cb5b2c401241ee87f8ffd27
Reviewed-on: https://chromium-review.googlesource.com/1226120
Commit-Queue: Joshua Peraza <jperaza@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
The general strategy used by Crashpad to determine loaded modules is to
read the link_map to get the addresses of the dynamic arrays for all
loaded modules. Those addresses can then be used to query the MemoryMap
to locate the module's mappings, and in particular the base mapping
from which Crashpad can parse the entire loaded ELF file.
ELF modules are typically loaded in several mappings with varying
permissions for different segments. The previous strategy used to find
the base mapping for a module was to search backwards from the mapping
for the dynamic array until a mapping from file offset 0 was found for
the same file. This fails when the file is mapped multiple times from
file offset 0, which can happen if the first page of the file contains
a GNU_RELRO segment.
This new strategy queries the MemoryMap for ALL mappings associated
with the dynamic array's mapping, mapped from offset 0. The consumer
(process_reader_linux.cc) can then determine which mapping is the
correct base by attempting to parse a module at that address and
corroborating the PT_DYNAMIC or program header table address from the
parsed module with the values Crashpad gets from the link_map or
auxiliary vector.
Bug: crashpad:30
Change-Id: Ibfcbba512e8fccc8c65afef734ea5640b71e9f70
Reviewed-on: https://chromium-review.googlesource.com/1139396
Commit-Queue: Joshua Peraza <jperaza@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
This is particularly a problem when the neighboring mapping is a
special mapping not readable from another process. For example:
7fff96aeb000-7fff96b0c000 rw-p 00000000 00:00 0 [stack]
7fff96b0c000-7fff96b0e000 r--p 00000000 00:00 0 [vvar]
[vvar] is a special mapping which makes some kernel data available
for virtual system calls. Attempting to read this region via the
/proc/<pid>/maps file returns an IO error which causes Crashpad to
abort capturing any of the thread's stack.
Neighboring mappings with empty names are eligible to be merged since
they result from changing permissions on existing named mappings.
Change-Id: I587bd2ec6f9759d284f1f9b1d93f2a44ddf61e92
Reviewed-on: https://chromium-review.googlesource.com/1072803
Reviewed-by: Scott Graham <scottmg@chromium.org>
Commit-Queue: Joshua Peraza <jperaza@chromium.org>
This change:
1. Updates the broker's memory reading protocol to enable short reads.
2. Updates Ptracer to allow short reads.
3. Updates the broker to allow reading from a memory file.
4. Updates the broker's default file root to be "/proc/[pid]/".
5. Adds PtraceConnection::Memory() to produce a suitable memory reader
for a connection type.
Bug: crashpad:30
Change-Id: I8c004016065d981acd1fa74ad1b8e51ce07c7c85
Reviewed-on: https://chromium-review.googlesource.com/991455
Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Joshua Peraza <jperaza@chromium.org>
Some files, such as /proc/[pid]/maps, may not be accessible to the
handler. This enables the handler access to the contents of those files
via the broker.
This change reads maps and auxv using ReadFileContents.
Bug: crashpad:30
Change-Id: Ia19b498bae473c616ea794ab51c3f22afd5795be
Reviewed-on: https://chromium-review.googlesource.com/989406
Reviewed-by: Mark Mentovai <mark@chromium.org>
