[elfabi] Add support for reading DT_NEEDED from binaries
This patch gives elfabi the ability to read DT_NEEDED entries from ELF binaries
to populate NeededLibs in TextAPI's ELFStub.
Differential Revision: https://reviews.llvm.org/D55852
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351592 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/tools/llvm-elfabi/binary-read-neededlibs-bad-offset.test b/test/tools/llvm-elfabi/binary-read-neededlibs-bad-offset.test
new file mode 100644
index 0000000..439ca5c
--- /dev/null
+++ b/test/tools/llvm-elfabi/binary-read-neededlibs-bad-offset.test
@@ -0,0 +1,45 @@
+# RUN: yaml2obj %s > %t
+# RUN: not llvm-elfabi --elf %t --emit-tbe=%t.tbe 2>&1 | FileCheck %s
+
+!ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_DYN
+ Machine: EM_X86_64
+Sections:
+ - Name: .dynstr
+ Type: SHT_STRTAB
+ Flags: [ SHF_ALLOC ]
+ Address: 0x1000
+ # "\0libfoo.so\0libbar.so\0somelib.so\0foo\0"
+ Content: "006c6962666f6f2e736f006c69626261722e736f00736f6d656c69622e736f00666f6f00"
+ - Name: .dynamic
+ Type: SHT_DYNAMIC
+ Flags: [ SHF_ALLOC ]
+ Address: 0x1024
+ Content: "010000000000000001000000000000000e0000000000000015000000000000000100000000000000ffff0000000000000a0000000000000024000000000000000500000000000000001000000000000000000000000000000000000000000000"
+ # DT_NEEDED 1 (0x01)
+ # DT_SONAME 21 (0x15)
+ # Bad DT_NEEDED entry (offset outside string table):
+ # DT_NEEDED 65535 (0xffff)
+ # DT_STRSZ 36 (0x24)
+ # DT_STRTAB 0x1000
+ # DT_NULL 0x0
+ Size: 96
+ProgramHeaders:
+ - Type: PT_LOAD
+ Flags: [ PF_R ]
+ VAddr: 0x1000
+ PAddr: 0x1000
+ Align: 8
+ Sections:
+ - Section: .dynstr
+ - Section: .dynamic
+ - Type: PT_DYNAMIC
+ Flags: [ PF_X, PF_R ]
+ VAddr: 0x1024
+ PAddr: 0x1024
+ Sections:
+
+# CHECK: DT_NEEDED string offset (0x000000000000ffff) outside of dynamic string table
diff --git a/test/tools/llvm-elfabi/binary-read-neededlibs.test b/test/tools/llvm-elfabi/binary-read-neededlibs.test
new file mode 100644
index 0000000..4245d19
--- /dev/null
+++ b/test/tools/llvm-elfabi/binary-read-neededlibs.test
@@ -0,0 +1,47 @@
+# RUN: yaml2obj %s -o %t
+# RUN: llvm-elfabi --elf %t --emit-tbe=- | FileCheck %s
+
+!ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_DYN
+ Machine: EM_X86_64
+Sections:
+ - Name: .dynstr
+ Type: SHT_STRTAB
+ Flags: [ SHF_ALLOC ]
+ Address: 0x1000
+ # "\0libfoo.so\0libbar.so\0somelib.so\0foo\0"
+ Content: "006c6962666f6f2e736f006c69626261722e736f00736f6d656c69622e736f00666f6f00"
+ - Name: .dynamic
+ Type: SHT_DYNAMIC
+ Flags: [ SHF_ALLOC ]
+ Address: 0x1024
+ Content: "010000000000000001000000000000000e00000000000000150000000000000001000000000000000b000000000000000a0000000000000024000000000000000500000000000000001000000000000000000000000000000000000000000000"
+ # DT_NEEDED 1 (0x01)
+ # DT_SONAME 21 (0x15)
+ # DT_NEEDED 11 (0x0b)
+ # DT_STRSZ 36 (0x24)
+ # DT_STRTAB 0x1000
+ # DT_NULL 0x0
+ Size: 96
+ProgramHeaders:
+ - Type: PT_LOAD
+ Flags: [ PF_R ]
+ VAddr: 0x1000
+ PAddr: 0x1000
+ Align: 8
+ Sections:
+ - Section: .dynstr
+ - Section: .dynamic
+ - Type: PT_DYNAMIC
+ Flags: [ PF_X, PF_R ]
+ VAddr: 0x1024
+ PAddr: 0x1024
+ Sections:
+
+# CHECK: NeededLibs:
+# CHECK-NEXT: - libfoo.so{{$}}
+# CHECK-NEXT: - libbar.so{{$}}
+# CHECK-NEXT: Symbols: {}
diff --git a/tools/llvm-elfabi/ELFObjHandler.cpp b/tools/llvm-elfabi/ELFObjHandler.cpp
index 4c8e61d..d60bd5c 100644
--- a/tools/llvm-elfabi/ELFObjHandler.cpp
+++ b/tools/llvm-elfabi/ELFObjHandler.cpp
@@ -31,6 +31,7 @@
uint64_t StrTabAddr = 0;
uint64_t StrSize = 0;
Optional<uint64_t> SONameOffset;
+ std::vector<uint64_t> NeededLibNames;
};
/// This function behaves similarly to StringRef::substr(), but attempts to
@@ -94,6 +95,9 @@
Dyn.StrSize = Entry.d_un.d_val;
FoundDynStrSz = true;
break;
+ case DT_NEEDED:
+ Dyn.NeededLibNames.push_back(Entry.d_un.d_val);
+ break;
}
}
@@ -111,6 +115,14 @@
"DT_SONAME string offset (0x%016x) outside of dynamic string table",
*Dyn.SONameOffset);
}
+ for (uint64_t Offset : Dyn.NeededLibNames) {
+ if (Offset >= Dyn.StrSize) {
+ return createStringError(
+ object_error::parse_failed,
+ "DT_NEEDED string offset (0x%016x) outside of dynamic string table",
+ Offset);
+ }
+ }
return Error::success();
}
@@ -164,7 +176,16 @@
DestStub->SoName = *NameOrErr;
}
- // TODO: Populate NeededLibs from .dynamic entries and linked string table.
+ // Populate NeededLibs from .dynamic entries and dynamic string table.
+ for (uint64_t NeededStrOffset : DynEnt.NeededLibNames) {
+ Expected<StringRef> LibNameOrErr =
+ terminatedSubstr(DynStr, NeededStrOffset);
+ if (!LibNameOrErr) {
+ return appendToError(LibNameOrErr.takeError(), "when reading DT_NEEDED");
+ }
+ DestStub->NeededLibs.push_back(*LibNameOrErr);
+ }
+
// TODO: Populate Symbols from .dynsym table and linked string table.
return std::move(DestStub);