Commit graph

55 commits

Author SHA1 Message Date
Kalesh Singh
c5c1d19ebb loader: Only extend segments if kernel supports page size migration
It has been found that some existing apps have implicit dependencies on
the address ranges in /proc/*/maps. Since segment extension changes the
range of the LOAD segment VMAs some of these apps crash, either by
SIGBUS or in yet unidentified ways.

Only perform the segment extension optimization if the kernel has the
necessary mitigations to ensure app compatibility.

Bug: 330117029
Bug: 327600007
Bug: 330767927
Bug: 328266487
Bug: 329803029
Test: Manual - Launch Free Fire Chaos app
Change-Id: I5b03b22c4a468f6646750a00942cc2d57f43d0de
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
2024-05-02 11:06:51 -07:00
Elliott Hughes
396868c747 [[nodiscard]] the various ElfReader functions.
These are either only useful for their side-effects, or things you
really need to check.

Change-Id: I8e231185eb7fc8656fd3cb916169661833b525bf
2024-04-10 21:52:10 +00:00
Kalesh Singh
702d9b0bad Reapply "RELAND: bionic: loader: Extend GNU_RELRO protection"
This reverts commit 26de64896c.

Bug: 328797737
Test: Dexcom G7 app
Change-Id: I98882edd17f0ea5432ab254482ab9508bfaf4f56
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
2024-03-13 13:38:44 -07:00
Kalesh Singh
4084b555b2 Reapply "RELAND: bionic: loader: Extend LOAD segment VMAs"
This reverts commit 7a04fedc78.

Test: Dexcom G7 app
Bug: 328797737
Change-Id: I575d626b1313d1c66bf25f29c43a9a101024a4f8
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
2024-03-13 13:37:30 -07:00
Kalesh Singh
7a04fedc78 Revert "RELAND: bionic: loader: Extend LOAD segment VMAs"
Revert submission 2966884

Reason for revert: b/328266487

Reverted changes: /q/submissionid:2966884

Bug: 328266487
Change-Id: I45a2c5888eefab36c069f992de00ec8c87105288
2024-03-07 13:32:34 -08:00
Kalesh Singh
26de64896c Revert "RELAND: bionic: loader: Extend GNU_RELRO protection"
Revert submission 2966884

Reason for revert: b/328266487

Reverted changes: /q/submissionid:2966884

Bug: 328266487
Change-Id: I3e61443302bf7fd8f58c843c9d7dc3c747897959
2024-03-07 13:32:23 -08:00
Kalesh Singh
41b8863cd7 RELAND: bionic: loader: Extend GNU_RELRO protection
If the LOAD segment VMAs are extended to prevent creating additional
VMAs, the the protection extent of the GNU_RELRO segment must also
be updated to match. Otherwise, the partial mprotect will reintroduce
an additional VMA due to the split protections.

Update the GNU_RELRO protection range when the ELF was loaded by the
bionic loader. Be careful not to attempt any fix up for ELFs not loaded
by us (e.g. ELF loaded by the kernel) since these don't have the
extended VMA fix to begin with.

Consider a system with 4KB page size and the ELF files with 64K
alignment. e.g:

$ readelf -Wl /system/lib64/bootstrap/libc.so | grep 'Type\|LOAD'

Type           Offset   VirtAddr           PhysAddr           FileSiz  MemSiz   Flg Align
LOAD           0x000000 0x0000000000000000 0x0000000000000000 0x0441a8 0x0441a8 R   0x10000
LOAD           0x0441b0 0x00000000000541b0 0x00000000000541b0 0x091860 0x091860 R E 0x10000
LOAD           0x0d5a10 0x00000000000f5a10 0x00000000000f5a10 0x003d40 0x003d40 RW  0x10000
LOAD           0x0d9760 0x0000000000109760 0x0000000000109760 0x0005c0 0x459844 RW  0x10000

Before this patch:

$ cat /proc/1/maps | grep -A1 libc.so

7f468f069000-7f468f0bd000 r--p 00000000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f0bd000-7f468f15e000 r-xp 00044000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f15e000-7f468f163000 r--p 000d5000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f163000-7f468f172000 rw-p 000da000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f172000-7f468f173000 rw-p 000d9000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f173000-7f468f5c4000 rw-p 00000000 00:00 0                          [anon:.bss]

1 extra RW VMA at offset 0x000da000 (3 RW mappings in total)

After this patch:

$ cat /proc/1/maps | grep -A1 libc.so

7f5a50225000-7f5a50279000 r--p 00000000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f5a50279000-7f5a5031a000 r-xp 00044000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f5a5031a000-7f5a5032e000 r--p 000d5000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f5a5032e000-7f5a5032f000 rw-p 000d9000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f5a5032f000-7f5a50780000 rw-p 00000000 00:00 0                          [anon:.bss]

Removed RW VMA at offset 0x000da000 (2 RW mappings in total)

Bug: 316403210
Bug: 300367402
Bug: 307803052
Bug: 312550202
Test: atest -c linker-unit-tests
Test: atest -c bionic-unit-tests
Change-Id: I9cd04574190ef4c727308363a8cb1120c36e53e0
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
2024-02-27 07:19:07 +00:00
Kalesh Singh
944164c5e2 RELAND: bionic: loader: Extend LOAD segment VMAs
When the page_size < p_align of the ELF load segment, the loader
will end up creating extra PROT_NONE gap VMA mappings between the
LOAD segments. This problem is exacerbated by Android's zygote
model, where the number of loaded .so's can lead to ~30MB increase
in vm_area_struct unreclaimable slab memory.

Extend the LOAD segment VMA's to cover the range between the
segment's end and the start of the next segment, being careful
to avoid touching regions of the extended mapping where the offset
would overrun the size of the file. This avoids the loader
creating an additional gap VMA for each LOAD segment.

Consider a system with 4KB page size and the ELF files with 64K
alignment. e.g:

$ readelf -Wl /system/lib64/bootstrap/libc.so | grep 'Type\|LOAD'

Type           Offset   VirtAddr           PhysAddr           FileSiz  MemSiz   Flg Align
LOAD           0x000000 0x0000000000000000 0x0000000000000000 0x0441a8 0x0441a8 R   0x10000
LOAD           0x0441b0 0x00000000000541b0 0x00000000000541b0 0x091860 0x091860 R E 0x10000
LOAD           0x0d5a10 0x00000000000f5a10 0x00000000000f5a10 0x003d40 0x003d40 RW  0x10000
LOAD           0x0d9760 0x0000000000109760 0x0000000000109760 0x0005c0 0x459844 RW  0x10000

Before this patch:

$ cat /proc/1/maps | grep -A1 libc.so

7fa1d4a90000-7fa1d4ad5000 r--p 00000000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7fa1d4ad5000-7fa1d4ae4000 ---p 00000000 00:00 0
7fa1d4ae4000-7fa1d4b76000 r-xp 00044000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7fa1d4b76000-7fa1d4b85000 ---p 00000000 00:00 0
7fa1d4b85000-7fa1d4b8a000 r--p 000d5000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7fa1d4b8a000-7fa1d4b99000 ---p 00000000 00:00 0
7fa1d4b99000-7fa1d4b9a000 rw-p 000d9000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7fa1d4b9a000-7fa1d4feb000 rw-p 00000000 00:00 0                          [anon:.bss]

3 additional PROT_NONE (---p) VMAs for gap mappings.

After this patch:

$ cat /proc/1/maps | grep -A1 libc.so

7f468f069000-7f468f0bd000 r--p 00000000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f0bd000-7f468f15e000 r-xp 00044000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f15e000-7f468f163000 r--p 000d5000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f163000-7f468f172000 rw-p 000da000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f172000-7f468f173000 rw-p 000d9000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f173000-7f468f5c4000 rw-p 00000000 00:00 0                          [anon:.bss]

No additional gap VMAs. However notice there is an extra RW VMA at
offset 0x000da000. This is caused by the RO protection of the
GNU_RELRO segment, which causes the extended RW VMA to split.
The GNU_RELRO protection extension is handled in the subsequent
patch in this series.

Bug: 316403210
Bug: 300367402
Bug: 307803052
Bug: 312550202
Test: atest -c linker-unit-tests
Test: atest -c bionic-unit-tests
Change-Id: I7150ed22af0723cc0b2d326c046e4e4a8b56ad09
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
2024-02-27 06:13:11 +00:00
Zheng Pan
92a7e1c55c Revert "bionic: loader: Extend LOAD segment VMAs"
Revert submission 2803156-loader_crt_pad_segment

Reason for revert: b/324952273

Reverted changes: /q/submissionid:2803156-loader_crt_pad_segment

Change-Id: I8af115c426c0113914abbf8fbd3e74c0d89408d1
2024-02-14 00:04:10 +00:00
Zheng Pan
9535c32e1c Revert "bionic: loader: Extend GNU_RELRO protection"
Revert submission 2803156-loader_crt_pad_segment

Reason for revert: b/324952273

Reverted changes: /q/submissionid:2803156-loader_crt_pad_segment

Change-Id: I22d4ae1972c5de7da908eb090a2fea5565ead88b
2024-02-14 00:04:10 +00:00
Kalesh Singh
33f89709bc bionic: loader: Extend GNU_RELRO protection
If the LOAD segment VMAs are extended to prevent creating additional
VMAs, the the protection extent of the GNU_RELRO segment must also
be updated to match. Otherwise, the partial mprotect will reintroduce
an additional VMA due to the split protections.

Update the GNU_RELRO protection range when the ELF was loaded by the
bionic loader. Be careful not to attempt any fix up for ELFs not loaded
by us (e.g. ELF loaded by the kernel) since these don't have the
extended VMA fix to begin with.

Consider a system with 4KB page size and the ELF files with 64K
alignment. e.g:

$ readelf -Wl /system/lib64/bootstrap/libc.so | grep 'Type\|LOAD'

Type           Offset   VirtAddr           PhysAddr           FileSiz  MemSiz   Flg Align
LOAD           0x000000 0x0000000000000000 0x0000000000000000 0x0441a8 0x0441a8 R   0x10000
LOAD           0x0441b0 0x00000000000541b0 0x00000000000541b0 0x091860 0x091860 R E 0x10000
LOAD           0x0d5a10 0x00000000000f5a10 0x00000000000f5a10 0x003d40 0x003d40 RW  0x10000
LOAD           0x0d9760 0x0000000000109760 0x0000000000109760 0x0005c0 0x459844 RW  0x10000

Before this patch:

$ cat /proc/1/maps | grep -A1 libc.so

7f468f069000-7f468f0bd000 r--p 00000000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f0bd000-7f468f15e000 r-xp 00044000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f15e000-7f468f163000 r--p 000d5000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f163000-7f468f172000 rw-p 000da000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f172000-7f468f173000 rw-p 000d9000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f173000-7f468f5c4000 rw-p 00000000 00:00 0                          [anon:.bss]

1 extra RW VMA at offset 0x000da000 (3 RW mappings in total)

After this patch:

$ cat /proc/1/maps | grep -A1 libc.so

7f5a50225000-7f5a50279000 r--p 00000000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f5a50279000-7f5a5031a000 r-xp 00044000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f5a5031a000-7f5a5032e000 r--p 000d5000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f5a5032e000-7f5a5032f000 rw-p 000d9000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f5a5032f000-7f5a50780000 rw-p 00000000 00:00 0                          [anon:.bss]

Removed RW VMA at offset 0x000da000 (2 RW mappings in total)

Bug: 316403210
Bug: 300367402
Bug: 307803052
Bug: 312550202
Test: atest -c linker-unit-tests [ Later patch ]
Test: atest -c bionic-unit-tests
Change-Id: If1d99e8b872fcf7f6e0feb02ff33503029b63be3
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
2024-02-08 13:07:06 -08:00
Kalesh Singh
4b4fb6f439 bionic: loader: Extend LOAD segment VMAs
When the page_size < p_align of the ELF load segment, the loader
will end up creating extra PROT_NONE gap VMA mappings between the
LOAD segments. This problem is exacerbated by Android's zygote
model, where the number of loaded .so's can lead to ~30MB increase
in vm_area_struct unreclaimable slab memory.

Extend the LOAD segment VMA's to cover the range between the
segment's end and the start of the next segment, being careful
to avoid touching regions of the extended mapping where the offset
would overrun the size of the file. This avoids the loader
creating an additional gap VMA for each LOAD segment.

Consider a system with 4KB page size and the ELF files with 64K
alignment. e.g:

$ readelf -Wl /system/lib64/bootstrap/libc.so | grep 'Type\|LOAD'

Type           Offset   VirtAddr           PhysAddr           FileSiz  MemSiz   Flg Align
LOAD           0x000000 0x0000000000000000 0x0000000000000000 0x0441a8 0x0441a8 R   0x10000
LOAD           0x0441b0 0x00000000000541b0 0x00000000000541b0 0x091860 0x091860 R E 0x10000
LOAD           0x0d5a10 0x00000000000f5a10 0x00000000000f5a10 0x003d40 0x003d40 RW  0x10000
LOAD           0x0d9760 0x0000000000109760 0x0000000000109760 0x0005c0 0x459844 RW  0x10000

Before this patch:

$ cat /proc/1/maps | grep -A1 libc.so

7fa1d4a90000-7fa1d4ad5000 r--p 00000000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7fa1d4ad5000-7fa1d4ae4000 ---p 00000000 00:00 0
7fa1d4ae4000-7fa1d4b76000 r-xp 00044000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7fa1d4b76000-7fa1d4b85000 ---p 00000000 00:00 0
7fa1d4b85000-7fa1d4b8a000 r--p 000d5000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7fa1d4b8a000-7fa1d4b99000 ---p 00000000 00:00 0
7fa1d4b99000-7fa1d4b9a000 rw-p 000d9000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7fa1d4b9a000-7fa1d4feb000 rw-p 00000000 00:00 0                          [anon:.bss]

3 additional PROT_NONE (---p) VMAs for gap mappings.

After this patch:

$ cat /proc/1/maps | grep -A1 libc.so

7f468f069000-7f468f0bd000 r--p 00000000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f0bd000-7f468f15e000 r-xp 00044000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f15e000-7f468f163000 r--p 000d5000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f163000-7f468f172000 rw-p 000da000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f172000-7f468f173000 rw-p 000d9000 fe:09 20635520                   /system/lib64/bootstrap/libc.so
7f468f173000-7f468f5c4000 rw-p 00000000 00:00 0                          [anon:.bss]

No additional gap VMAs. However notice there is an extra RW VMA at
offset 0x000da000. This is caused by the RO protection of the
GNU_RELRO segment, which causes the extended RW VMA to split.
The GNU_RELRO protection extension is handled in the subsequent
patch in this series.

Bug: 316403210
Bug: 300367402
Bug: 307803052
Bug: 312550202
Test: atest -c linker-unit-tests [Later patch]
Test: atest -c bionic-unit-tests
Change-Id: I3363172c02d5a4e2b2a39c44809e433a4716bc45
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
2024-02-08 13:07:04 -08:00
Kalesh Singh
377f0b9138 bionic: Introduce ElfReader::ReadPadSegmentNote()
ReadPadSegmentNote() finds the elf note of type
NT_ANDROID_TYPE_PAD_SEGMENT and checks that the desc value
is 1, to decided whether the LOAD segment mappings should
be extended (padded) to avoid gaps.

Cache the result of this operation in ElfReader and soinfo
for use in the subsequent patch which handles the extension
of the segment mappings.

Test: atest -c linker-unit-tests [Later patch]
Test: m && launch_cvd
Bug: 316403210
Change-Id: I32c05cce741d221c3f92835ea09d932c40bdf8b1
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
2024-02-06 17:59:01 -08:00
Evgenii Stepanov
6bbb75aa77 Revert "Linker support for MTE globals."
Revert submission 2709995

Reason for revert: linker crash in soinfo::apply_relr_reloc

Reverted changes: /q/submissionid:2709995

Bug: 314038442
Change-Id: I2c6ad7f46fb1174f009253602ad08ceb36aa7d71
2023-12-06 19:01:46 +00:00
Mitch Phillips
e8139f585a Linker support for MTE globals.
This patch adds the necessary bionic code for the linker to protect
global data using MTE.

The implementation is described in the MemtagABI addendum to the
AArch64 ELF ABI:
https://github.com/ARM-software/abi-aa/blob/main/memtagabielf64/memtagabielf64.rst

In summary, this patch includes:

1. When MTE globals is requested, the linker maps writable SHF_ALLOC
   sections as anonymous pages with PROT_MTE (copying the file contents
   into the anonymous mapping), rather than using a file-backed private
   mapping. This is required as file-based mappings are not necessarily
   backed by the kernel with tag-capable memory. For sections already
   mapped by the kernel when the linker is invoked via. PT_INTERP, we
   unmap the contents, remap a PROT_MTE+anonymous mapping in its place,
   and re-load the file contents from disk.

2. When MTE globals is requested, the linker tags areas of global memory
   (as defined in SHT_AARCH64_MEMTAG_GLOBALS_DYNAMIC) with random tags,
   but ensuring that adjacent globals are never tagged using the same
   memory tag (to provide detemrinistic overflow detection).

3. Changes to RELATIVE, ABS64, and GLOB_DAT relocations to load and
   store tags in the right places. This ensures that the address tags are
   materialized into the GOT entries as well. These changes are a
   functional no-op to existing binaries and/or non-MTE capable hardware.

Bug: N/A
Test: atest bionic-unit-tests CtsBionicTestCases --test-filter=*Memtag*

Change-Id: Id7b1a925339b14949d5a8f607dd86928624bda0e
2023-11-20 15:53:06 +01:00
Collin Fijalkovich
47d27aa79c Bionic: Mark PMD aligned text segments huge page eligible
To take advantage of file-backed huge pages for the text segments of key
shared libraries (go/android-hugepages), the dynamic linker must load
candidate ELF files at an appropriately aligned address and mark
executable segments with MADV_HUGEPAGE.

This patches uses segments' p_align values to determine when a file is
PMD aligned (2MB alignment), and performs load operations accordingly.

Bug: 158135888
Test: Verified PMD aligned libraries are backed with huge pages on
supporting kernel versions.

Change-Id: Ia2367fd5652f663d50103e18f7695c59dc31c7b9
2021-05-06 13:15:11 -07:00
Tamas Petz
8d55d1872a Enable BTI in bionic linker
This patch adds support to load BTI-enabled objects.

According to the ABI, BTI is recorded in the .note.gnu.property section.
The new parser evaluates the property section, if exists.
It searches for .note section with NT_GNU_PROPERTY_TYPE_0.
Once found it tries to find GNU_PROPERTY_AARCH64_FEATURE_1_AND.
The results are cached.

The main change in linker is when protection of loaded ranges gets
applied. When BTI is requested and the platform also supports it
the prot flags have to be amended with PROT_BTI for executable ranges.
Failing to add PROT_BTI flag would disable BTI protection.
Moreover, adding the new PROT flag for shared objects without BTI
compatibility would break applications.

Kernel does not add PROT_BTI to a loaded ELF which has interpreter.
Linker handles this case too.

Test: 1. Flame boots
      2. Tested on FVP with BTI enabled

Change-Id: Iafdf223b74c6e75d9f17ca90500e6fe42c4c1218
2020-09-23 17:53:28 -07:00
Evgenii Stepanov
e0848bbf89 Pagetable-friendly shared library address randomization.
Add inaccessible gaps between shared libraries to make it harder for the
attackers to defeat ASLR by random probing.

To avoid excessive page table bloat, only do this when a library is
about to cross a huge page boundary, effectively allowing several
smaller libraries to be lumped together.

Bug: 158113540
Test: look at /proc/$$/maps
Change-Id: I39c0100b81f72447e8b3c6faafa561111492bf8c
2020-07-16 13:57:20 -07:00
Evgenii Stepanov
474f2f5c8b Revert "Add randomized padding around shared library mappings."
This reverts commit a8cf3fef2a.

Reason for revert: memory regression due to the fragmentation of the page tables
Bug: 159810641
Bug: 158113540

Change-Id: I6212c623ff440c7f6889f0a1e82cf7a96200a411
2020-07-06 19:27:55 +00:00
Evgenii Stepanov
a8cf3fef2a Add randomized padding around shared library mappings.
Improve ASLR by increasing the randomly sized gaps between shared
library mappings, and keep them mapped PROT_NONE.

Bug: 158113540
Test: look at /proc/$$/maps
Change-Id: Ie72c84047fb624fe2ac8b7744b2a2d0d255ea974
2020-06-17 17:28:28 -07:00
Torne (Richard Coles)
fa9f7f28d4 Fix DLEXT_WRITE_RELRO when loading multiple libs.
ANDROID_DLEXT_WRITE_RELRO was causing the GNU RELRO sections of
libraries to become corrupted if more than one library was being loaded
at once (i.e. if the root library has DT_NEEDED entries for libraries
that weren't already loaded). The file offset was not being correctly
propagated between calls, so after writing out the (correct) RELRO data
to the file, it was mapping the data at file offset 0 for all libraries,
which corrupted the data for all but one of the libraries.

Fix this by passing file_offset as a pointer the same way that
phdr_table_map_gnu_relro does.

Bug: 128623590
Test: tbd
Change-Id: I196cd336bd5a67454e89fd85487356b1c7856871
2019-04-02 18:06:12 -04:00
Torne (Richard Coles)
efbe9a5eef linker: allow using reserved space for multiple libraries.
Introduce a new flag ANDROID_DLEXT_RESERVED_ADDRESS_RECURSIVE which
instructs the linker to use the reserved address space to load all of
the newly-loaded libraries required by a dlopen() call instead of only
the main library. They will be loaded consecutively into that region if
they fit. The RELRO sections of all the loaded libraries will also be
considered for reading/writing shared RELRO data.

This will allow the WebView implementation to potentially consist of
more than one .so file while still benefiting from the RELRO sharing
optimisation, which would otherwise only apply to the "root" .so file.

Test: bionic-unit-tests (existing and newly added)
Bug: 110790153
Change-Id: I61da775c29fd5017d9a1e2b6b3757c3d20a355b3
2019-02-20 17:29:36 -05:00
Ryan Prichard
8f639a4096 Allow invoking the linker on an executable.
The executable can be inside a zip file using the same syntax used for
shared objects: path.zip!/libentry.so.

The linker currently requires an absolute path. This restriction could be
loosened, but it didn't seem important? If it allowed non-absolute paths,
we'd need to decide how to handle:
 - foo/bar      (relative to CWD?)
 - foo          (search PATH / LD_LIBRARY_PATH, or also relative to CWD?)
 - foo.zip!/bar (normalize_path() requires an absolute path)

The linker adjusts the argc/argv passed to main() and to constructor
functions to hide the initial linker argument, but doesn't adjust the auxv
vector or files like /proc/self/{exe,cmdline,auxv,stat}. Those files will
report that the kernel loaded the linker as an executable.

I think the linker_logger.cpp change guarding against (g_argv == NULL)
isn't actually necessary, but it seemed like a good idea given that I'm
delaying initialization of g_argv until after C++ constructors have run.

Bug: http://b/112050209
Test: bionic unit tests
Change-Id: I846faf98b16fd34218946f6167e8b451897debe5
2018-10-10 14:31:06 -07:00
Elliott Hughes
cbc80ba9d8 Switch the rest of our internal headers to #pragma once.
We've been using #pragma once for new internal files, but let's be more bold.

Bug: N/A
Test: builds
Change-Id: I7e2ee2730043bd884f9571cdbd8b524043030c07
2018-02-13 14:27:17 -08:00
Dimitry Ivanov
7e2d49ae3e Check alignment along with range of mapped file fragments
Improve sanity-checks of elf-file by adding alignment check
of mapped sections and section headers.

Bug: http://b/30687964
Change-Id: I7f06ddaa56a13989ce7be847b3a73c352e32c008
2016-08-09 11:07:33 -07:00
Dimitry Ivanov
f45b0e9ede Do not unmap reserved region on dlclose
dlclose used to unmap the part of the reserved region
for ANDROID_DLEXT_RESERVED_ADDRESS that was neccessary
to map PT_LOAD segments. With this change dlclose
replaces mapped PT_LOAD segments with a PROT_NONE,
MAP_ANONYMOUS | MAP_NORESERVE.

Previously caller was unmapping the reserved region after
the failed dlclose which led to race condition when someone
else reused the region freed by dlclose but before the unmap
by the chromium code.

Bug: http://code.google.com/p/chromium/issues/detail?id=568880
Change-Id: I0f5eaa2bf6641f83dde469b631c518482acc59a2
2016-01-20 20:57:47 -08:00
Dmitriy Ivanov
3c5248182e Handling invalid section headers
The linker crashes if native library has invalid section
headers. This change adds boundary checks on target offsets
and generates dlerror instead of crash.

Bug: http://b/25800330
Change-Id: Ibe282029997302b9b557637c3aad064d7d0febc5
2015-11-22 23:25:06 -08:00
Dmitriy Ivanov
4f7a7ad3fe Implement Library Load Order Randomization
Bug: http://b/24047022
Change-Id: I36e05b403bfbaae8542a95147f9114a8b9c8ac0e
2015-10-22 18:26:07 -07:00
Dmitriy Ivanov
cf1cbbe432 refactoring: introduce MappedFileFragment
Change-Id: I97b0c1131711ed0ac13ab33e3357e99e0b6b1a4e
2015-10-22 18:01:56 -07:00
Evgenii Stepanov
d640b225ec A special linker for ASan executables.
Setup a /system/bin/linker_asan as a symlink to "linker".
Read the linker name from PT_INTERP, and if it is linker_asan,
switch default library lookup paths to the ASan set, which
starts with the path to the instrumented libraries
(/data/lib), followed by /system/lib as a fallback.

This ensures that ASan binaries prefer ASan libraries, when
available. This approach is way better then RPATH/RUNPATH and even
better than LD_LIBRARY_PATH:
- RUNPATH is per-DSO, while default paths are global.
- LD_LIBRARY_PATH is overwritten by android_update_LD_LIBRARY_PATH.
- neither RUNPATH nor LD_LIBRARY_PATH appear in
  android_get_LD_LIBRARY_PATH which is used to build java.lang.path.
  Having ASan libraries in java.lang.path is a good thing.

Bug: 22355945
Change-Id: I1d2791fbf5740618f18f71a3ae3d873714669d3f
2015-07-14 16:12:27 -07:00
Dmitriy Ivanov
3f987f5b3e Fix crash when trying to load invalid ELF file.
Bug: http://b/22047255
Bug: http://b/22091640
Change-Id: I6c51cff43287a6ac4b25fa9ce6a6fc3d232fd047
(cherry picked from commit 06700b2b5e)
2015-06-25 20:05:50 -07:00
Dimitry Ivanov
56be6ed9e4 Revert "Remove text-relocation support for lp32"
This reverts commit cb00add1b3.

Bug: 20020312
Bug: 20013628
Change-Id: I8baa3d4b6c7fef50c9e2531257d5b96762099eb3
2015-04-01 21:18:48 +00:00
Dmitriy Ivanov
cb00add1b3 Remove text-relocation support for lp32
Bug: 20013628
Change-Id: Idaf8012f00ee1304d429c3b42f9ebc6b648c55b8
2015-03-31 17:42:45 -07:00
Dmitriy Ivanov
20d89cb5b0 Fix long lines and replace macros with functions.
Change-Id: I4e1cab488d5b2c8e4289da617350a86e72a4ba12
2015-03-31 11:49:25 -07:00
Dmitriy Ivanov
1649e7ee5b Enable -Wold-style-cast warnings for linker
And fix old style casts.

Change-Id: I37e7a3e3fd852528ea76f02d967c7bd8cd5b06c9
2015-01-22 16:33:30 -08:00
Dmitriy Ivanov
07e5bc152d Add file_offset parameter to android_extinfo
Bug: 17762003
Change-Id: I8fb267a3155acef3dba534038cf5d1ef00d7154b
2014-10-06 10:02:34 -07:00
Ningsheng Jian
e93be99da0 Fix gdb could not get shared library list issue
Get dynamic flags from phdr table's correct entry rather the first
entry, so that the following DT_DEBUG entry can be set.

Also fix the undefined reference to LoadTask::deleter issue under gcc
-O0 option.

Bug: 17524778
Change-Id: I9c679af197b034761fb739d6c980e628ff2ab84c
2014-09-26 22:58:57 +00:00
Dmitriy Ivanov
14669a939d Load libraries in breadth-first order
This patch fixes the problem with symbol search order
  for dlsym(RTLD_DEFAULT/RTLD_NEXT, .) by loading libraries
  and ld_preloads in correct order.

Bug: https://code.google.com/p/android/issues/detail?id=74255
Change-Id: If1ba5c807322409faa914e27ecb675e2c4541f0d
Attempt: 2
2014-09-08 13:02:50 -07:00
Dmitriy Ivanov
498eb18b82 Revert "Load libraries in breadth-first order"
This reverts commit a3ad450a2e.

Change-Id: Ia2b838ad2159c643b80c514849582f4b4f4f40e5
2014-09-05 16:27:54 -07:00
Dmitriy Ivanov
a3ad450a2e Load libraries in breadth-first order
This patch fixes the problem with symbol search order
  for dlsym(RTLD_DEFAULT/RTLD_NEXT, .) by loading libraries
  and ld_preloads in correct order.

Bug: https://code.google.com/p/android/issues/detail?id=74255
Change-Id: I4cf84c70dbaabe99310230dfda12385ae5401859
2014-09-03 15:06:14 -07:00
Dmitriy Ivanov
851135bf99 Replace NULL with nullptr
Change-Id: Iad50be617d318ca98883b843229c960ad5b9afa9
2014-08-29 14:13:48 -07:00
Torne (Richard Coles)
183ad9df53 Allow sharing the RELRO section via a file.
Add flags and a file descriptor to android_dlopen_ext() to allow writing
the RELRO section of the loaded library to a file after relocation
processing, and to allow mapping identical pages from the file over the
top of relocated memory in another process. Explicitly comparing the
pages is required in case a page contains a reference to a symbol
defined in another library loaded at a random base address.

Bug: 13005501
Change-Id: Ibb5b2d384edfaa5acf3e97a5f8b6115c10497a1e
2014-04-17 14:30:46 +01:00
Torne (Richard Coles)
12bbb91645 Support loading libraries to a reserved address.
Add flags and parameters to android_dlopen_ext() to allow loading a
library at an already-reserved fixed address. If the library to be
loaded will not fit within the space reserved, then the linker will
either fail, or allocate its own address space as usual, according to
which flag has been specified. This behaviour only applies to the
specific library requested; any other libraries loaded as dependencies
will be loaded in the normal fashion.

There is a new gtest included to cover the functionality added.

Bug: 13005501
Change-Id: I5d1810375b20fc51ba6a9b3191a25f9792c687f1
2014-04-17 14:22:17 +01:00
Elliott Hughes
0266ae5f88 Switch <elf.h> over to linux uapi under the covers.
Remove the linker's reliance on BSD cruft and use the glibc-style
ElfW macro. (Other code too, but the linker contains the majority
of the code that needs to work for Elf32 and Elf64.)

All platforms need dl_iterate_phdr_static, so it doesn't make sense
to have that part of the per-architecture configuration.

Bug: 12476126
Change-Id: I1d7f918f1303a392794a6cd8b3512ff56bd6e487
2014-02-10 18:22:24 -08:00
Elliott Hughes
4eeb1f12a8 Clean up linker architecture macros.
We don't need our own architecture macros; the standard ones will do.

This patch also fixes some __x86_64__ tests to be USE_RELA tests instead,
because they're not actually x86_64-specific.

I've cleaned up architecture-specific code slightly so where possible
all the code corresponding to a particular architecture is together.

This patch also fixes a bug in LP64 DT_PLTGOT handling, which should be
an error rather than falling through into DT_DEBUG! There was another #ifdef
bug where we'd only report unexpected DT_ entries on MIPS.

Change-Id: Id1d04e372611f641c1aa278a18e379f28af9eaf5
2013-10-28 11:02:49 -07:00
Elliott Hughes
c00f2cb587 x86_64 linker.
Based on I8dc3e2cb596f75dc58ae82e4dc58f8c177dd3323 by
Pavel Chupin <pavel.v.chupin@intel.com>.

Change-Id: Icd582d277cbe273477b450f2848343d72c86ec9f
2013-10-08 09:57:01 -07:00
Elliott Hughes
c620059479 Remove 32-bit assumptions from the ELF code.
Change-Id: I2c1f3d34c33685799aade8866eec44479ff9f963
2013-09-30 18:43:46 -07:00
Brian Carlstrom
e7dffe150b Honor p_vaddr if set
(cherry picked from commit 88ff15c2c279d2bbe3569101b36cd2aa0931a0a9)

Change-Id: I4aabbe911d30aea8ace69e29bb6e980a4e89de90
2013-06-07 12:47:58 -07:00
Elliott Hughes
650be4e584 More linker cleanup.
Change-Id: I9fb3c7c0d4b4ffef0eeaf092d4e30ffe63a08671
2013-03-05 22:24:34 -08:00
Brian Carlstrom
d4ee82dfa3 Minor linker cleanup, primarily to use Elf32_Dyn
Change-Id: Ifa9408e9859c6f79444715bed4808b7c13fdced5
2013-03-05 15:27:21 -08:00