We did not set DF_1_GLOBAL flag for LD_PRELOADed
libraries which led to the situation when ld_preloads
where ignored during on dlopen()
Change-Id: I696b3b2506a8ed4c0984ad2c803210a7a4f8e686
This change adds realpath to soinfo and
extends limit on filenames from 128 to PATH_MAX.
It also removes soinfo::name field, linker uses
dt_soname instead.
Bug: http://b/19818481
Bug: https://code.google.com/p/android/issues/detail?id=80336
Change-Id: I9cff4cb5bda3ee2bc74e1bbded9594ea7fbe2a08
This flag allows to force loading of the library
in the case when for some reason multiple ELF files
share the same filename (because the already-loaded
library has been removed and overwritten, for example).
Change-Id: I798d44409ee13d63eaa75d685e99c4d028d2b0c1
When the Android dynamic linker handles a text relocation,
it first relaxes the permissions on the segment being modified,
performs the modifications, and then restores the page permissions.
The relaxation worked by adding PROT_WRITE to whatever protection
bits were set in the section. In effect, the pages were getting set
to PROT_READ|PROT_WRITE|PROT_EXEC, modified, then restored to
PROT_READ|PROT_EXEC
The SELinux kernel code differentiates between 4 different kinds
of executable memory:
* Executable stack (execstack)
* Executable heap (execheap)
* File-based executable code which has been modified (execmod)
* All other executable memory (execmem)
The execmod capability is only triggered by the kernel when a
dirty but non-executable mmap()ed page becomes executable. When that
occurs, an SELinux policy check is done to see if the execmod capability
is provided by policy.
However, if the page is already executable, and PROT_WRITE is added
to the page, it's considered an execmem permission check, not an execmod
permission check.
There are certain circumstances where we may want to distinguish between
execmod and execmem. This change adjusts the dynamic linker to avoid
using RWX pages, so that an RX -> RW -> RX transition will properly
be detected as an execmod permission check instead of an execmem permission
check.
Bug: 20013628
Change-Id: I14d7be29170b156942f9809023f3b2fc1f37846c
Add code to support loading shared libraries directly from within
APK files.
Extends the linker's handling of LD_LIBRARY_PATH, DT_RUNPATH, etc
to allow elements to be either directories as normal, or ZIP
format files. For ZIP, the ZIP subdirectory string is separated
from the path to file by '!'.
For example, if DT_NEEDED is libchrome.so and Chrome.apk is the
Android ARM APK then the path element
/system/app/Chrome.apk!lib/armeabi-v7a
would cause the linker to load lib/armeabi-v7a/libchrome.so
directly from inside Chrome.apk. For loading to succeed,
libchrome.so must be 'stored' and not compressed in Chrome.apk,
and must be page aligned within the file.
Motivation:
Chromium tracking issue:
https://code.google.com/p/chromium/issues/detail?id=390618
Bug: 8076853
Change-Id: Ic49046600b1417eae3ee8f37ee98c8ac1ecc19e7
Add basic general purpose memory allocator to
linker in order to enable usage of other libraries
like libziparchive.
Change-Id: I4a680ebb36ed5ba67c61249f81dba9f567808434
Kindle app relies on soinfo's sysv hash
fields while linking native libraries.
This change allows to keep sysv hash fields
intact for the libraries linked with --hash-style=both.
Bug: 19059885
Change-Id: I12528652955638f1a6586bda99e111bb1c8aa7a3
When the kernel executes a program which is setuid, setgid, has
file capabilities, or causes an SELinux domain transition, the
AT_SECURE flag is set. This flag instructs the dynamic linker to
prune any dangerous environment variables passed across security
boundaries.
For SELinux in particular, whether this flag is set depends on the
the "noatsecure" process permission. If that permission does not
exist, then AT_SECURE=1 whenever a domain transition occurs.
In https://android-review.googlesource.com/129971 , Android stopped
using noatsecure when executing init services. In
https://android-review.googlesource.com/130610 , init was flipped
back into SELinux enforcing mode, making ag/129971 active. The
combination of those two changes ensured that AT_SECURE=1 was
set when executing init spawned services.
In particular, AT_SECURE=1 is set when init executes zygote. Due to
the forking nature of zygote, AT_SECURE remains untouched when
executing zygote's children.
This causes problems for the code added in
https://android-review.googlesource.com/48409 . Specifically, if
AT_SECURE=1, an attempt to call android_update_LD_LIBRARY_PATH()
is silently ignored. This causes problems when art tries to adjust
the LD_LIBRARY_PATH for Android apps. Ultimately, apps are unable
to find shared libraries they depend on.
As discussed in bug 7896159, there's no security reason for
preventing an application from updating it's own LD_LIBRARY_PATH.
We only need to prune LD_LIBRARY_PATH when transitioning across
security boundaries, but not when we're entirely within a security
boundary.
Remove the AT_SECURE check within do_android_update_LD_LIBRARY_PATH().
It's unneeded and prevents an application from modifying it's own
LD_LIBRARY_PATH. This allows an application to specify a location
where it's dlopen()ed shared libraries should be loaded from.
There is no change to AT_SECURE handling in
__sanitize_environment_variables(). We continue to honor it there
to prevent using security sensitive environment variables across
an exec boundary.
Bug: 19559835
Change-Id: If4af2ee8e84265aaa0c93de8b281208b20d7942a
load_bias is the delta between a symbols address in memory and the value
contained in the symbol table.
Change-Id: I35c87b69025b64f7e4a1418ca766618f4533fb3e
If two or more threads crash at the same time, only let one talk to
debuggerd. It's possible for a race to occur that two threads send
data to debuggerd, the second one will cause errors in debuggerd since
the process will die once debuggerd lets the crashing pid start again.
Bug: 19183955
Change-Id: I17dfce46102117ab4a870f7381bd526488d37fb5
Implement refcounter based data protection guard
to avoid unnecessary calls to mprotect when dlopen/dlclose
is called from a constructor.
Bug: 19124318
Big: 7941716
Change-Id: Id221b84ce75443094f99756dc9950b0a1dc87222
Handy when looking at strace output for seeing "where does my code start?",
though you'll need to set LD_DEBUG=1 (or greater) and constructors will
already have run (but you can set LD_DEBUG to a higher value to track that).
Change-Id: I82d53a7123b39febf5b2a956de83c8a30f229651
Must build this linker as a shared object.
A statically linked module does not load during init.
BUG: 18008984
Change-Id: I5f0411129024edcb9381c473ea4e741a075e9184
Make the request structure match the new structure found in debuggerd
code.
On 64 bit systems, make sure that the 32 bit compiled linker is contacted.
Bug: https://code.google.com/p/android/issues/detail?id=97024
Change-Id: I675b8ff222fcf836b05de4e9b5976ff91ca929bf
