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cmake/debian/patches/mips-rld-map-rel.patch

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From c51099bb1018191964e5ee05e17f133233160806 Mon Sep 17 00:00:00 2001
From: James Cowgill <jcowgill@debian.org>
Date: Thu, 13 Oct 2016 11:00:00 +0100
Subject: [PATCH] MIPS: Handle DT_MIPS_RLD_MAP_REL tag when removing RPath from
ELFs
This is a combination of 5 commits.
elf: remove tag switch from ELF_Dyn ByteSwap function
elf: add DynamicEntryList methods and rpath tag constants
cmSystemTools: rewrite RemoveRPath using DyanmicEntryList methods
cmSystemTools, elf: handle DT_MIPS_RLD_REL_MAP in RemoveRPath
elf: Remove GetDynamicEntryCount and ReadBytes methods
diff --git a/Source/cmELF.cxx b/Source/cmELF.cxx
index 2d86674..0655da9 100644
--- a/Source/cmELF.cxx
+++ b/Source/cmELF.cxx
@@ -132,18 +132,13 @@ public:
// Forward to the per-class implementation.
virtual unsigned int GetNumberOfSections() const = 0;
- virtual unsigned int GetDynamicEntryCount() = 0;
virtual unsigned long GetDynamicEntryPosition(int j) = 0;
+ virtual cmELF::DynamicEntryList GetDynamicEntries() = 0;
+ virtual std::vector<char> EncodeDynamicEntries(
+ const cmELF::DynamicEntryList&) = 0;
virtual StringEntry const* GetDynamicSectionString(unsigned int tag) = 0;
virtual void PrintInfo(std::ostream& os) const = 0;
- bool ReadBytes(unsigned long pos, unsigned long size, char* buf)
- {
- this->Stream.seekg(pos);
- this->Stream.read(buf, size);
- return !this->Stream.fail();
- }
-
// Lookup the SONAME in the DYNAMIC section.
StringEntry const* GetSOName()
{
@@ -246,10 +241,13 @@ public:
return static_cast<unsigned int>(this->ELFHeader.e_shnum);
}
- // Get the file position and size of a dynamic section entry.
- unsigned int GetDynamicEntryCount() CM_OVERRIDE;
+ // Get the file position of a dynamic section entry.
unsigned long GetDynamicEntryPosition(int j) CM_OVERRIDE;
+ cmELF::DynamicEntryList GetDynamicEntries() CM_OVERRIDE;
+ std::vector<char> EncodeDynamicEntries(const cmELF::DynamicEntryList&)
+ CM_OVERRIDE;
+
// Lookup a string from the dynamic section with the given tag.
StringEntry const* GetDynamicSectionString(unsigned int tag) CM_OVERRIDE;
@@ -289,6 +287,10 @@ public:
}
private:
+ // ByteSwap(ELF_Dyn) assumes d_val and d_ptr are the same size
+ typedef char dyn_size_assert
+ [sizeof(ELF_Dyn().d_un.d_val) == sizeof(ELF_Dyn().d_un.d_ptr) ? 1 : -1];
+
void ByteSwap(ELF_Ehdr& elf_header)
{
cmELFByteSwap(elf_header.e_type);
@@ -323,121 +325,7 @@ private:
void ByteSwap(ELF_Dyn& dyn)
{
cmELFByteSwap(dyn.d_tag);
- switch (dyn.d_tag) {
- case DT_NULL: /* dyn.d_un ignored */
- break;
- case DT_NEEDED:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
- case DT_PLTRELSZ:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
- case DT_PLTGOT:
- cmELFByteSwap(dyn.d_un.d_ptr);
- break;
- case DT_HASH:
- cmELFByteSwap(dyn.d_un.d_ptr);
- break;
- case DT_STRTAB:
- cmELFByteSwap(dyn.d_un.d_ptr);
- break;
- case DT_SYMTAB:
- cmELFByteSwap(dyn.d_un.d_ptr);
- break;
- case DT_RELA:
- cmELFByteSwap(dyn.d_un.d_ptr);
- break;
- case DT_RELASZ:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
- case DT_RELAENT:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
- case DT_STRSZ:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
- case DT_SYMENT:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
- case DT_INIT:
- cmELFByteSwap(dyn.d_un.d_ptr);
- break;
- case DT_FINI:
- cmELFByteSwap(dyn.d_un.d_ptr);
- break;
- case DT_SONAME:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
- case DT_RPATH:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
- case DT_SYMBOLIC: /* dyn.d_un ignored */
- break;
- case DT_REL:
- cmELFByteSwap(dyn.d_un.d_ptr);
- break;
- case DT_RELSZ:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
- case DT_RELENT:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
- case DT_PLTREL:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
- case DT_DEBUG:
- cmELFByteSwap(dyn.d_un.d_ptr);
- break;
- case DT_TEXTREL: /* dyn.d_un ignored */
- break;
- case DT_JMPREL:
- cmELFByteSwap(dyn.d_un.d_ptr);
- break;
-#ifdef T_BIND_NOW
- case T_BIND_NOW: /* dyn.d_un ignored */
- break;
-#endif
-#ifdef DT_INIT_ARRAY
- case DT_INIT_ARRAY:
- cmELFByteSwap(dyn.d_un.d_ptr);
- break;
-#endif
-#ifdef DT_FINI_ARRAY
- case DT_FINI_ARRAY:
- cmELFByteSwap(dyn.d_un.d_ptr);
- break;
-#endif
-#ifdef DT_INIT_ARRAYSZ
- case DT_INIT_ARRAYSZ:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
-#endif
-#ifdef DT_FINI_ARRAYSZ
- case DT_FINI_ARRAYSZ:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
-#endif
-#ifdef DT_RUNPATH
- case DT_RUNPATH:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
-#endif
-#ifdef DT_FLAGS
- case DT_FLAGS:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
-#endif
-#ifdef DT_PREINIT_ARRAY
- case DT_PREINIT_ARRAY:
- cmELFByteSwap(dyn.d_un.d_ptr);
- break;
-#endif
-#ifdef DT_PREINIT_ARRAYSZ
- case DT_PREINIT_ARRAYSZ:
- cmELFByteSwap(dyn.d_un.d_val);
- break;
-#endif
- }
+ cmELFByteSwap(dyn.d_un.d_val);
}
bool FileTypeValid(ELF_Half et)
@@ -636,30 +524,64 @@ bool cmELFInternalImpl<Types>::LoadDynamicSection()
}
template <class Types>
-unsigned int cmELFInternalImpl<Types>::GetDynamicEntryCount()
+unsigned long cmELFInternalImpl<Types>::GetDynamicEntryPosition(int j)
{
if (!this->LoadDynamicSection()) {
return 0;
}
- for (unsigned int i = 0; i < this->DynamicSectionEntries.size(); ++i) {
- if (this->DynamicSectionEntries[i].d_tag == DT_NULL) {
- return i;
- }
+ if (j < 0 || j >= static_cast<int>(this->DynamicSectionEntries.size())) {
+ return 0;
}
- return static_cast<unsigned int>(this->DynamicSectionEntries.size());
+ ELF_Shdr const& sec = this->SectionHeaders[this->DynamicSectionIndex];
+ return static_cast<unsigned long>(sec.sh_offset + sec.sh_entsize * j);
}
template <class Types>
-unsigned long cmELFInternalImpl<Types>::GetDynamicEntryPosition(int j)
+cmELF::DynamicEntryList cmELFInternalImpl<Types>::GetDynamicEntries()
{
+ cmELF::DynamicEntryList result;
+
+ // Ensure entries have been read from file
if (!this->LoadDynamicSection()) {
- return 0;
+ return result;
}
- if (j < 0 || j >= static_cast<int>(this->DynamicSectionEntries.size())) {
- return 0;
+
+ // Copy into public array
+ result.reserve(this->DynamicSectionEntries.size());
+ for (typename std::vector<ELF_Dyn>::iterator di =
+ this->DynamicSectionEntries.begin();
+ di != this->DynamicSectionEntries.end(); ++di) {
+ ELF_Dyn& dyn = *di;
+ result.push_back(
+ std::pair<unsigned long, unsigned long>(dyn.d_tag, dyn.d_un.d_val));
}
- ELF_Shdr const& sec = this->SectionHeaders[this->DynamicSectionIndex];
- return static_cast<unsigned long>(sec.sh_offset + sec.sh_entsize * j);
+
+ return result;
+}
+
+template <class Types>
+std::vector<char> cmELFInternalImpl<Types>::EncodeDynamicEntries(
+ const cmELF::DynamicEntryList& entries)
+{
+ std::vector<char> result;
+ result.reserve(sizeof(ELF_Dyn) * entries.size());
+
+ for (cmELF::DynamicEntryList::const_iterator it = entries.begin();
+ it != entries.end(); it++) {
+ // Store the entry in an ELF_Dyn, byteswap it, then serialize to chars
+ ELF_Dyn dyn;
+ dyn.d_tag = static_cast<tagtype>(it->first);
+ dyn.d_un.d_val = static_cast<tagtype>(it->second);
+
+ if (this->NeedSwap) {
+ ByteSwap(dyn);
+ }
+
+ char* pdyn = reinterpret_cast<char*>(&dyn);
+ result.insert(result.end(), pdyn, pdyn + sizeof(ELF_Dyn));
+ }
+
+ return result;
}
template <class Types>
@@ -752,6 +674,15 @@ cmELF::StringEntry const* cmELFInternalImpl<Types>::GetDynamicSectionString(
//============================================================================
// External class implementation.
+const long cmELF::TagRPath = DT_RPATH;
+const long cmELF::TagRunPath = DT_RUNPATH;
+
+#ifdef DT_MIPS_RLD_MAP_REL
+const long cmELF::TagMipsRldMapRel = DT_MIPS_RLD_MAP_REL;
+#else
+const long cmELF::TagMipsRldMapRel = 0;
+#endif
+
cmELF::cmELF(const char* fname)
: Internal(CM_NULLPTR)
{
@@ -839,28 +770,31 @@ unsigned int cmELF::GetNumberOfSections() const
return 0;
}
-unsigned int cmELF::GetDynamicEntryCount() const
+unsigned long cmELF::GetDynamicEntryPosition(int index) const
{
if (this->Valid()) {
- return this->Internal->GetDynamicEntryCount();
+ return this->Internal->GetDynamicEntryPosition(index);
}
return 0;
}
-unsigned long cmELF::GetDynamicEntryPosition(int index) const
+cmELF::DynamicEntryList cmELF::GetDynamicEntries() const
{
if (this->Valid()) {
- return this->Internal->GetDynamicEntryPosition(index);
+ return this->Internal->GetDynamicEntries();
}
- return 0;
+
+ return cmELF::DynamicEntryList();
}
-bool cmELF::ReadBytes(unsigned long pos, unsigned long size, char* buf) const
+std::vector<char> cmELF::EncodeDynamicEntries(
+ const cmELF::DynamicEntryList& dentries) const
{
if (this->Valid()) {
- return this->Internal->ReadBytes(pos, size, buf);
+ return this->Internal->EncodeDynamicEntries(dentries);
}
- return false;
+
+ return std::vector<char>();
}
bool cmELF::GetSOName(std::string& soname)
diff --git a/Source/cmELF.h b/Source/cmELF.h
index 7e7c1d6..763a240 100644
--- a/Source/cmELF.h
+++ b/Source/cmELF.h
@@ -7,6 +7,8 @@
#include <iosfwd>
#include <string>
+#include <utility>
+#include <vector>
#if !defined(CMAKE_USE_ELF_PARSER)
#error "This file may be included only if CMAKE_USE_ELF_PARSER is enabled."
@@ -61,22 +63,27 @@ public:
int IndexInSection;
};
+ /** Represent entire dynamic section header */
+ typedef std::vector<std::pair<long, unsigned long> > DynamicEntryList;
+
/** Get the type of the file opened. */
FileType GetFileType() const;
/** Get the number of ELF sections present. */
unsigned int GetNumberOfSections() const;
- /** Get the number of DYNAMIC section entries before the first
- DT_NULL. Returns zero on error. */
- unsigned int GetDynamicEntryCount() const;
-
/** Get the position of a DYNAMIC section header entry. Returns
zero on error. */
unsigned long GetDynamicEntryPosition(int index) const;
- /** Read bytes from the file. */
- bool ReadBytes(unsigned long pos, unsigned long size, char* buf) const;
+ /** Get a copy of all the DYNAMIC section header entries.
+ Returns an empty vector on error */
+ DynamicEntryList GetDynamicEntries() const;
+
+ /** Encodes a DYNAMIC section header entry list into a char vector according
+ to the type of ELF file this is */
+ std::vector<char> EncodeDynamicEntries(
+ const DynamicEntryList& entries) const;
/** Get the SONAME field if any. */
bool GetSOName(std::string& soname);
@@ -91,6 +98,10 @@ public:
/** Print human-readable information about the ELF file. */
void PrintInfo(std::ostream& os) const;
+ /** Interesting dynamic tags.
+ If the tag is 0, it does not exist in the host ELF implementation */
+ static const long TagRPath, TagRunPath, TagMipsRldMapRel;
+
private:
friend class cmELFInternal;
bool Valid() const;
diff --git a/Source/cmSystemTools.cxx b/Source/cmSystemTools.cxx
index 3d8fdf5..d800ef8 100644
--- a/Source/cmSystemTools.cxx
+++ b/Source/cmSystemTools.cxx
@@ -2518,9 +2518,9 @@ bool cmSystemTools::RemoveRPath(std::string const& file, std::string* emsg,
std::swap(se[0], se[1]);
}
- // Get the size of the dynamic section header.
- unsigned int count = elf.GetDynamicEntryCount();
- if (count == 0) {
+ // Obtain a copy of the dynamic entries
+ cmELF::DynamicEntryList dentries = elf.GetDynamicEntries();
+ if (dentries.empty()) {
// This should happen only for invalid ELF files where a DT_NULL
// appears before the end of the table.
if (emsg) {
@@ -2536,40 +2536,46 @@ bool cmSystemTools::RemoveRPath(std::string const& file, std::string* emsg,
zeroSize[i] = se[i]->Size;
}
- // Get the range of file positions corresponding to each entry and
- // the rest of the table after them.
- unsigned long entryBegin[3] = { 0, 0, 0 };
- unsigned long entryEnd[2] = { 0, 0 };
- for (int i = 0; i < se_count; ++i) {
- entryBegin[i] = elf.GetDynamicEntryPosition(se[i]->IndexInSection);
- entryEnd[i] = elf.GetDynamicEntryPosition(se[i]->IndexInSection + 1);
- }
- entryBegin[se_count] = elf.GetDynamicEntryPosition(count);
-
- // The data are to be written over the old table entries starting at
- // the first one being removed.
- bytesBegin = entryBegin[0];
- unsigned long bytesEnd = entryBegin[se_count];
+ // Get size of one DYNAMIC entry
+ unsigned long const sizeof_dentry =
+ elf.GetDynamicEntryPosition(1) - elf.GetDynamicEntryPosition(0);
- // Allocate a buffer to hold the part of the file to be written.
- // Initialize it with zeros.
- bytes.resize(bytesEnd - bytesBegin, 0);
-
- // Read the part of the DYNAMIC section header that will move.
- // The remainder of the buffer will be left with zeros which
- // represent a DT_NULL entry.
- char* data = &bytes[0];
- for (int i = 0; i < se_count; ++i) {
- // Read data between the entries being removed.
- unsigned long sz = entryBegin[i + 1] - entryEnd[i];
- if (sz > 0 && !elf.ReadBytes(entryEnd[i], sz, data)) {
- if (emsg) {
- *emsg = "Failed to read DYNAMIC section header.";
+ // Adjust the entry list as necessary to remove the run path
+ unsigned long entriesErased = 0;
+ for (cmELF::DynamicEntryList::iterator it = dentries.begin();
+ it != dentries.end();) {
+ if (it->first == cmELF::TagRPath || it->first == cmELF::TagRunPath) {
+ it = dentries.erase(it);
+ entriesErased++;
+ continue;
+ } else {
+ if (cmELF::TagMipsRldMapRel != 0 &&
+ it->first == cmELF::TagMipsRldMapRel) {
+ // Background: debuggers need to know the "linker map" which contains
+ // the addresses each dynamic object is loaded at. Most arches use
+ // the DT_DEBUG tag which the dynamic linker writes to (directly) and
+ // contain the location of the linker map, however on MIPS the
+ // .dynamic section is always read-only so this is not possible. MIPS
+ // objects instead contain a DT_MIPS_RLD_MAP tag which contains the
+ // address where the dyanmic linker will write to (an indirect
+ // version of DT_DEBUG). Since this doesn't work when using PIE, a
+ // relative equivalent was created - DT_MIPS_RLD_MAP_REL. Since this
+ // version contains a relative offset, moving it changes the
+ // calculated address. This may cause the dyanmic linker to write
+ // into memory it should not be changing.
+ //
+ // To fix this, we adjust the value of DT_MIPS_RLD_MAP_REL here. If
+ // we move it up by n bytes, we add n bytes to the value of this tag.
+ it->second += entriesErased * sizeof_dentry;
}
- return false;
+
+ it++;
}
- data += sz;
}
+
+ // Encode new entries list
+ bytes = elf.EncodeDynamicEntries(dentries);
+ bytesBegin = elf.GetDynamicEntryPosition(0);
}
// Open the file for update.
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