[lld] e73d0b5 - [COFF] Error on unexpected .pdata size

[Hans Wennborg via llvm-commits]

Author: Hans Wennborg
Date: 2020-07-13T13:38:39+02:00
New Revision: e73d0b5719966ddbeff7a3da70a3cb782c3733ed

URL: https://github.com/llvm/llvm-project/commit/e73d0b5719966ddbeff7a3da70a3cb782c3733ed
DIFF: https://github.com/llvm/llvm-project/commit/e73d0b5719966ddbeff7a3da70a3cb782c3733ed.diff

LOG: [COFF] Error on unexpected .pdata size

Previously, lld would crash if the .pdata size was not an even multiple
of the expected .pdata entry size. This makes it error gracefully instead.

(We hit this in Chromium due to an assembler problem: https://crbug.com/1101577)

Differential revision: https://reviews.llvm.org/D83479

Added: 
    lld/test/COFF/pdata-arm64-bad.yaml

Modified: 
    lld/COFF/Writer.cpp

Removed: 
    


################################################################################
diff  --git a/lld/COFF/Writer.cpp b/lld/COFF/Writer.cpp
index ffa0a0006f0e..3bcc1777f7ac 100644
--- a/lld/COFF/Writer.cpp
+++ b/lld/COFF/Writer.cpp
@@ -1864,6 +1864,10 @@ void Writer::sortExceptionTable() {
   uint8_t *end = bufAddr(lastPdata) + lastPdata->getSize();
   if (config->machine == AMD64) {
     struct Entry { ulittle32_t begin, end, unwind; };
+    if ((end - begin) % sizeof(Entry) != 0) {
+      fatal("unexpected .pdata size: " + Twine(end - begin) +
+            " is not a multiple of " + Twine(sizeof(Entry)));
+    }
     parallelSort(
         MutableArrayRef<Entry>((Entry *)begin, (Entry *)end),
         [](const Entry &a, const Entry &b) { return a.begin < b.begin; });
@@ -1871,6 +1875,10 @@ void Writer::sortExceptionTable() {
   }
   if (config->machine == ARMNT || config->machine == ARM64) {
     struct Entry { ulittle32_t begin, unwind; };
+    if ((end - begin) % sizeof(Entry) != 0) {
+      fatal("unexpected .pdata size: " + Twine(end - begin) +
+            " is not a multiple of " + Twine(sizeof(Entry)));
+    }
     parallelSort(
         MutableArrayRef<Entry>((Entry *)begin, (Entry *)end),
         [](const Entry &a, const Entry &b) { return a.begin < b.begin; });

diff  --git a/lld/test/COFF/pdata-arm64-bad.yaml b/lld/test/COFF/pdata-arm64-bad.yaml
new file mode 100644
index 000000000000..d6b496745795
--- /dev/null
+++ b/lld/test/COFF/pdata-arm64-bad.yaml
@@ -0,0 +1,89 @@
+# RUN: yaml2obj < %s > %t.obj
+# RUN: not lld-link /out:%t.exe /entry:func1 /subsystem:console %t.obj 2>&1 | FileCheck %s
+
+# This file is like pdata-arm64.yaml, except that .pdata has been extended with
+# 4 bytes. This can happen due to for example bad assembler input. Check that
+# lld errors gracefully instead of crashing.
+
+# CHECK: unexpected .pdata size: 20 is not a multiple of 8
+
+--- !COFF
+header:
+  Machine:         IMAGE_FILE_MACHINE_ARM64
+  Characteristics: [  ]
+sections:
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    Alignment:       4
+    SectionData:     ff4300d1f37b00a9f303012a00000094e003132a00000094f37b40a9ff430091c0035fd6f353bea9fe0b00f9f303012af403022a00000094e003132a00000094e003142a00000094fe0b40f9f353c2a8c0035fd6c0035fd6
+    Relocations:
+      - VirtualAddress:  12
+        SymbolName:      func3
+        Type:            IMAGE_REL_ARM64_BRANCH26
+      - VirtualAddress:  20
+        SymbolName:      func3
+        Type:            IMAGE_REL_ARM64_BRANCH26
+      - VirtualAddress:  52
+        SymbolName:      func3
+        Type:            IMAGE_REL_ARM64_BRANCH26
+      - VirtualAddress:  60
+        SymbolName:      func3
+        Type:            IMAGE_REL_ARM64_BRANCH26
+      - VirtualAddress:  68
+        SymbolName:      func3
+        Type:            IMAGE_REL_ARM64_BRANCH26
+  - Name:            .pdata
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]
+    Alignment:       4
+    SectionData:     0000000031002201000000002500a10000000000
+    Relocations:
+      - VirtualAddress:  0
+        SymbolName:      func2
+        Type:            IMAGE_REL_ARM64_ADDR32NB
+      - VirtualAddress:  8
+        SymbolName:      func1
+        Type:            IMAGE_REL_ARM64_ADDR32NB
+symbols:
+  - Name:            .text
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          57
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          1
+  - Name:            .pdata
+    Value:           0
+    SectionNumber:   2
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          20
+      NumberOfRelocations: 2
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          2
+  - Name:            func1
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            func2
+    Value:           36
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            func3
+    Value:           84
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+...