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[ELF] Allow misaligned SHT_GNU_verneed

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Bazel created interface shared objects (.ifso) may be misaligned.  We use
llvm::support::detail::packed_endian_specific_integral under the hood
which allows reading of misaligned values, so there is not a need to
diagnose (in LLD we don't intend to support sophisticated parsing for
SHT_GNU_*).
This commit is contained in:
Fangrui Song 2020-05-26 11:06:07 -07:00
parent d1f0a76b21
commit b8a3c618d6
2 changed files with 8 additions and 8 deletions
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6
lld/ELF/InputFiles.cpp
View file

@ -1224,14 +1224,12 @@ std::vector<uint32_t> SharedFile::parseVerneed(const ELFFile<ELFT> &obj,
ArrayRef<uint8_t> data = CHECK(obj.getSectionContents(sec), this);
const uint8_t *verneedBuf = data.begin();
for (unsigned i = 0; i != sec->sh_info; ++i) {
if (verneedBuf + sizeof(typename ELFT::Verneed) > data.end() ||
uintptr_t(verneedBuf) % sizeof(uint32_t) != 0)
if (verneedBuf + sizeof(typename ELFT::Verneed) > data.end())
fatal(toString(this) + " has an invalid Verneed");
auto *vn = reinterpret_cast<const typename ELFT::Verneed *>(verneedBuf);
const uint8_t *vernauxBuf = verneedBuf + vn->vn_aux;
for (unsigned j = 0; j != vn->vn_cnt; ++j) {
if (vernauxBuf + sizeof(typename ELFT::Vernaux) > data.end() ||
uintptr_t(vernauxBuf) % sizeof(uint32_t) != 0)
if (vernauxBuf + sizeof(typename ELFT::Vernaux) > data.end())
fatal(toString(this) + " has an invalid Vernaux");
auto *aux = reinterpret_cast<const typename ELFT::Vernaux *>(vernauxBuf);
if (aux->vna_name >= this->stringTable.size())

10
lld/test/ELF/invalid/verneed-shared.yaml → lld/test/ELF/invalid/verneed-shared.test
View file

@ -6,7 +6,7 @@
## sh_offset(SHT_GNU_verneed) is out of bounds.
# RUN: yaml2obj --docnum=1 %s -o %t1.so
# RUN: not ld.lld %t.o %t1.so -o /dev/null 2>&1 | FileCheck --check-prefix=SHOFFSET %s
# SHOFFSET: error: {{.*}}.so: section [index 1] has a sh_offset (0xffffffff) + sh_size (0x0) that is greater than the file size (0x228)
# SHOFFSET: error: {{.*}}.so: section [index 1] has a sh_offset (0xffffffff) + sh_size (0x0) that is greater than the file size (0x168)
--- !ELF
FileHeader:
Class: ELFCLASS64
@ -17,12 +17,14 @@ Sections:
- Name: .gnu.version_r
Type: SHT_GNU_verneed
Flags: [ SHF_ALLOC ]
Info: 1
ShOffset: 0xFFFFFFFF
## A Verneed entry is misaligned (not a multiple of 4).
## A Verneed entry is misaligned (not a multiple of 4). This may happen
## some interface shared objects. We use memcpy to read the fields, so
## misalignment isn't a problem and there is no need to diagnose.
# RUN: yaml2obj --docnum=2 %s -o %t2.so
# RUN: not ld.lld %t.o %t2.so -o /dev/null 2>&1 | FileCheck --check-prefix=VN-MISALIGNED %s
# VN-MISALIGNED: {{.*}}.so has an invalid Verneed
# RUN: ld.lld %t.o %t2.so -o /dev/null
--- !ELF
FileHeader:
Class: ELFCLASS64