[llvm] 7ab1481 - [llvm-readelf/llvm-readobj] - Check version of SHT_GNU_verdef section entries when dumping.

[Georgii Rymar via llvm-commits]

Author: Georgii Rymar
Date: 2019-11-29T11:09:56+03:00
New Revision: 7ab14813619189d13382da047409a81c94ebc58d

URL: https://github.com/llvm/llvm-project/commit/7ab14813619189d13382da047409a81c94ebc58d
DIFF: https://github.com/llvm/llvm-project/commit/7ab14813619189d13382da047409a81c94ebc58d.diff

LOG: [llvm-readelf/llvm-readobj] - Check version of SHT_GNU_verdef section entries when dumping.

Elfxx_Verdef contains the following field:

vd_version
Version revision. This field shall be set to 1.
(https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/symversion.html)

Our code should check the struct version for correctness. This patch does that.
(This will help to simplify or eliminate ELFDumper<ELFT>::LoadVersionDefs() which
has it's own logic to parse version definitions for no reason. It checks the
struct version currently).

Differential revision: https://reviews.llvm.org/D70810

Added: 
    

Modified: 
    llvm/test/tools/llvm-readobj/elf-verdef-invalid.test
    llvm/tools/llvm-readobj/ELFDumper.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/test/tools/llvm-readobj/elf-verdef-invalid.test b/llvm/test/tools/llvm-readobj/elf-verdef-invalid.test
index 3a4de3698385..44be4f2fdac4 100644
--- a/llvm/test/tools/llvm-readobj/elf-verdef-invalid.test
+++ b/llvm/test/tools/llvm-readobj/elf-verdef-invalid.test
@@ -91,7 +91,7 @@ Sections:
     Link:    .dynstr
     Info:    0x1
     Entries:
-      - Version:    0
+      - Version:    1
         Flags:      0
         VersionNdx: 0
         Hash:       0
@@ -122,7 +122,7 @@ Sections:
     Link:    .dynstr
     Info:    0x1
     Entries:
-      - Version:    0
+      - Version:    1
         Flags:      0
         VersionNdx: 0
         Hash:       0
@@ -141,7 +141,7 @@ DynamicSymbols:
 
 # PAST-STRTAB-END-LLVM:      VersionDefinitions [
 # PAST-STRTAB-END-LLVM-NEXT:   Definition {
-# PAST-STRTAB-END-LLVM-NEXT:     Version: 0
+# PAST-STRTAB-END-LLVM-NEXT:     Version: 1
 # PAST-STRTAB-END-LLVM-NEXT:     Flags [ (0x0)
 # PAST-STRTAB-END-LLVM-NEXT:     ]
 # PAST-STRTAB-END-LLVM-NEXT:     Index: 0
@@ -153,7 +153,7 @@ DynamicSymbols:
 
 # PAST-STRTAB-END-GNU:      Version definition section '.gnu.version_d' contains 1 entries:
 # PAST-STRTAB-END-GNU-NEXT:  Addr: 0000000000000000  Offset: 0x000040  Link: 2 (.strtab)
-# PAST-STRTAB-END-GNU-NEXT:   0x0000: Rev: 0  Flags: none  Index: 0  Cnt: 1  Name: <invalid vda_name: 5>
+# PAST-STRTAB-END-GNU-NEXT:   0x0000: Rev: 1  Flags: none  Index: 0  Cnt: 1  Name: <invalid vda_name: 5>
 
 --- !ELF
 FileHeader:
@@ -167,7 +167,7 @@ Sections:
     Link:    .strtab
     Info:    0x1
     Entries:
-      - Version:    0
+      - Version:    1
         Flags:      0
         VersionNdx: 0
         Hash:       0
@@ -200,7 +200,7 @@ Sections:
     Link: .dynstr
     Info: 0x1
     Entries:
-      - Version:    0
+      - Version:    1
         Flags:      0
         VersionNdx: 0
         Hash:       0
@@ -230,7 +230,35 @@ Sections:
     Link:  .dynstr
     Info:  0x1
 ## The byte offset to the auxiliary entry is 0x13, i.e. it is not correctly aligned in memory.
-    Content: "0000000000000100000000001300000000000000"
+    Content: "0100000000000100000000001300000000000000"
 DynamicSymbols:
   - Name:    foo
     Binding: STB_GLOBAL
+
+## Check how we handle the case when a version definition entry has an unsupported version.
+
+# RUN: yaml2obj %s --docnum=9 -o %t9
+# RUN: llvm-readobj -V %t9 2>&1 | FileCheck %s --check-prefix=UNSUPPORTED-VERSION -DFILE=%t9
+# RUN: llvm-readelf -V %t9 2>&1 | FileCheck %s --check-prefix=UNSUPPORTED-VERSION -DFILE=%t9
+
+# UNSUPPORTED-VERSION: warning: '[[FILE]]': unable to dump SHT_GNU_verdef section with index 1: version 65278 is not yet supported
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+Sections:
+  - Name: .gnu.version_d
+    Type: SHT_GNU_verdef
+    Link: .dynstr
+    Info: 0x1
+    Entries:
+      - Version:    0xfefe
+        Flags:      0
+        VersionNdx: 0
+        Hash:       0
+        Names: []
+DynamicSymbols:
+  - Name: foo

diff  --git a/llvm/tools/llvm-readobj/ELFDumper.cpp b/llvm/tools/llvm-readobj/ELFDumper.cpp
index 79d08d379a1a..51ea599f4be7 100644
--- a/llvm/tools/llvm-readobj/ELFDumper.cpp
+++ b/llvm/tools/llvm-readobj/ELFDumper.cpp
@@ -409,6 +409,12 @@ ELFDumper<ELFT>::getVersionDefinitions(const Elf_Shdr *Sec) const {
           ": found a misaligned version definition entry at offset 0x" +
           Twine::utohexstr(VerdefBuf - Start));
 
+    unsigned Version = *reinterpret_cast<const Elf_Half *>(VerdefBuf);
+    if (Version != 1)
+      return createError("unable to dump SHT_GNU_verdef section with index " +
+                         Twine(SecNdx) + ": version " + Twine(Version) +
+                         " is not yet supported");
+
     const Elf_Verdef *D = reinterpret_cast<const Elf_Verdef *>(VerdefBuf);
     VerDef &VD = *Ret.emplace(Ret.end());
     VD.Offset = VerdefBuf - Start;