The previous implementation wasn't wrong (it returned the "maximum
maximum"), but we can return the actual runtime value from the kernel.
Noticed while looking at initgroups().
Test: treehugger
Change-Id: I891fe4ff29bd82ee05d9e05ed8299d32c21abd7f
GNU readelf accepts both `--header` and `--headers`, but we don't ship
that in the NDK any more, so anyone on macOS or Windows will hit this
incompatibility (even though Linux users are probably still using GNU
readelf).
Test: treehugger
Change-Id: I61eb389d4d9c0bc4f5d75ceefeb5709345299585
llvm-libc will reuse parts of the existing system headers for types that have
implications on the ABI.
Fixes:
error: external/llvm-libc/Android.bp:3:1: module "llvmlibc" variant
"android_recovery_riscv64_static": depends on //bionic/libc:libc_headers
which is not visible to this module You may need to add
"//external/llvm-libc" to its visibility
Test: TH
Bug: 321313756
Change-Id: I33b93d8e1617a480249641dc2cdf4bbee9f9e19d
Some obfuscated ELFs may containe "empty" PT_NOTEs (p_memsz == 0).
Attempting to mmap these will cause a EINVAL failure since the requested
mapping size is zero.
Skip these phrogram headers when parsing notes.
Also improve the failure log with arguments to the mmap syscall.
Test: Platinum Tests
Bug: 324468126
Change-Id: I7de4e55c6d221d555faabfcc33bb6997921dd022
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
These files were segregated because they were lacking a little cleanup.
Unfortunately that means this change has to do some of the cleanup, but
that's probably for the best.
Test: treehugger
Change-Id: I2dd33504787fc3313995de99e0745a0df22915b3
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>
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>
The PAD_SEGMENT note is used to optimize memory usage of the loader.
If the note parsing fails, skip the optimization and continue
loading the ELF normally.
Bug: 324309329
Bug: 316403210
Change-Id: I2aabc9f399816c53eb33ff303208a16022571edf
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
This reverts commit 79c9694c91.
Reason for revert: DroidMonitor: Potential culprit for Bug b/324348078 - verifying through ABTD before revert submission. This is part of the standard investigation process, and does not mean your CL will be reverted.
Change-Id: I32f7bc824900e18a7d53b025ffe3aaef0ee71802
The libcs we use don't need these any more (if they ever did), and we
were setting these globally in the build system anyway.
Also remove the -D_LIBCPP_ENABLE_CXX17_REMOVED_BINDERS from versioner
which doesn't seem needed any more either.
Test: treehugger
Change-Id: I9fb225b085906a02918c5847401d6c59f7779581
kPageSize is needed to determine whether the loader needs to
extend VMAs to avoid gaps in the memory map when loading the ELF.
While at it, use kPageSize to generically deduce the PMD size and
replace the hardcoded 2MB PMD size.
Bug: 316403210
Test: atest -c linker-unit-tests [Later patch]
Test: m && launch_cvd
Change-Id: Ie770320e629c38149dc75dae1deb1e429dd1acf2
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
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>
Factor out generic __get_elf_note() logic and rename __get_elf_note() to
__find_elf_note(). Expose __get_elf_note() in libc/private/bionic_note.h
This will be used in the subsequent patch to test the presence of
NT_ANDROID_TYPE_PAD_SEGMENT note when loading segments.
Test: atest -c linker-unit-tests [Later patch]
Test: m && launch_cvd
Bug: 316403210
Change-Id: Ia7cb2f40b10cfaef402182a675087c8422b37e4d
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
