If a crash occurred as a result to a write to unwritable memory, it is reason
to suggest exploitability. The processor checks for a bad write by
disassembling the command that caused the crash by piping the raw bytes near
the instruction pointer through objdump. This allows the processor to see if
the instruction that caused the crash is a write to memory and where the
target of the address is located.
R=ivanpe@chromium.org
Review URL: https://codereview.chromium.org/1273823004
git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1497 4c0a9323-5329-0410-9bdc-e9ce6186880e
when checking exploitability rating.
Linux minidumps do not support MD_MEMORY_INFO_LIST_STREAM, meaning the
processor cannot retrieve its memory mappings. However, it has its own
stream, MD_LINUX_MAPS, which contains memory mappings specific to Linux
(it contains the contents of /proc/self/maps). This CL allows the minidump
to gather information from the memory mappings for Linux minidumps.
In addition, exploitability rating for Linux dumps now use memory mappings
instead of checking the ELF headers of binaries. The basis for the change
is that checking the ELF headers requires the minidumps to store the memory
from the ELF headers, while the memory mapping data is already present,
meaning the size of a minidump will be unchanged.
As a result, of removing ELF header analysis, two unit tests have been removed.
Arguably, the cases that those unit tests check do not merit a high
exploitability rating and do not warrant a solid conclusion that was given
earlier.
R=ivanpe@chromium.org
Review URL: https://codereview.chromium.org/1251593007
git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1476 4c0a9323-5329-0410-9bdc-e9ce6186880e
If the minidump module containing the instruction pointer has memory
containing the ELF header and program header table, when checking the
exploitability rating, the processor will use the ELF header data to determine
if the instruction pointer lies in an executable region of the module, rather
than just checking if it lies in a module.
R=ivanpe@chromium.org
Review URL: https://codereview.chromium.org/1233973002
git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1472 4c0a9323-5329-0410-9bdc-e9ce6186880e
When I first added the exception whitelist, I meant to put the check before
checking the location of the instruction pointer. (I didn't notice that it
was after the other check until now.) The whitelist check is to quickly rule
out minidumps, and if checking the instruction pointer provided any useful
information, it would be pretty indicative that the exception causing the
dump is interesting.
R=ivanpe@chromium.org
Review URL: https://codereview.chromium.org/1211253009
git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1469 4c0a9323-5329-0410-9bdc-e9ce6186880e
in valid code for Linux exploitability rating.
This CL adds to the Linux exploitability checker by verifying that the
instruction pointer is in valid code. Verification is done by obtaining a
memory mapping of the crash and checking if the instruction pointer lies in
an executable region. If there is no memory mapping, the instruction pointer
is checked to determine if it lies within a known module.
R=ivanpe@chromium.org
Review URL: https://codereview.chromium.org/1210493003
git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1464 4c0a9323-5329-0410-9bdc-e9ce6186880e
