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author | Nick Clifton <nickc@redhat.com> | 2014-08-20 16:10:29 +0100 |
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committer | Nick Clifton <nickc@redhat.com> | 2014-08-20 16:10:29 +0100 |
commit | 2d5c3743a3a223dc6467ff022124b4f2f1844c91 (patch) | |
tree | c8d626b5afab0f3a57911c01e6c5194ed7247310 | |
parent | d36430db79dc8eccb9cb188e1234f7ff044f79b4 (diff) | |
download | gdb-2d5c3743a3a223dc6467ff022124b4f2f1844c91.zip gdb-2d5c3743a3a223dc6467ff022124b4f2f1844c91.tar.gz gdb-2d5c3743a3a223dc6467ff022124b4f2f1844c91.tar.bz2 |
Enabling the HIGH_ENTROPY_VA flag allows the operating system to use
addresses outside of the 32-bit range before memory exhaustion. This
results in a higher entropy implementation of ASLR when used with the
DYNAMIC_BASE flag.
* include/coff/pe.h: Add HIGH_ENTROPY_VA flag
* ld/emultempl/pep.em: Add --high-entropy-va switch
* ld/ld.texinfo: Document the --high-entropy-va switch
-rw-r--r-- | include/coff/ChangeLog | 4 | ||||
-rw-r--r-- | include/coff/pe.h | 52 | ||||
-rw-r--r-- | ld/ChangeLog | 5 | ||||
-rw-r--r-- | ld/emultempl/pep.em | 7 | ||||
-rw-r--r-- | ld/ld.texinfo | 5 |
5 files changed, 48 insertions, 25 deletions
diff --git a/include/coff/ChangeLog b/include/coff/ChangeLog index d45ef3d..3f960a3 100644 --- a/include/coff/ChangeLog +++ b/include/coff/ChangeLog @@ -1,3 +1,7 @@ +2014-08-20 Daniel Micay <danielmicay@gmail.com> + + * pe.h: Add HIGH_ENTROPY_VA flag + 2014-04-22 Christian Svensson <blue@cmd.nu> * or32.h: Delete. diff --git a/include/coff/pe.h b/include/coff/pe.h index 0ed9dde..b0fc707 100644 --- a/include/coff/pe.h +++ b/include/coff/pe.h @@ -40,6 +40,7 @@ /* DllCharacteristics flag bits. The inconsistent naming may seem odd, but that is how they are defined in the PE specification. */ +#define IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA 0x0020 #define IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE 0x0040 #define IMAGE_DLL_CHARACTERISTICS_FORCE_INTEGRITY 0x0080 #define IMAGE_DLL_CHARACTERISTICS_NX_COMPAT 0x0100 @@ -59,16 +60,16 @@ /* Section characteristics added for ppc-nt. */ -#define IMAGE_SCN_TYPE_NO_PAD 0x00000008 /* Reserved. */ +#define IMAGE_SCN_TYPE_NO_PAD 0x00000008 /* Reserved. */ -#define IMAGE_SCN_CNT_CODE 0x00000020 /* Section contains code. */ -#define IMAGE_SCN_CNT_INITIALIZED_DATA 0x00000040 /* Section contains initialized data. */ -#define IMAGE_SCN_CNT_UNINITIALIZED_DATA 0x00000080 /* Section contains uninitialized data. */ +#define IMAGE_SCN_CNT_CODE 0x00000020 /* Section contains code. */ +#define IMAGE_SCN_CNT_INITIALIZED_DATA 0x00000040 /* Section contains initialized data. */ +#define IMAGE_SCN_CNT_UNINITIALIZED_DATA 0x00000080 /* Section contains uninitialized data. */ -#define IMAGE_SCN_LNK_OTHER 0x00000100 /* Reserved. */ -#define IMAGE_SCN_LNK_INFO 0x00000200 /* Section contains comments or some other type of information. */ -#define IMAGE_SCN_LNK_REMOVE 0x00000800 /* Section contents will not become part of image. */ -#define IMAGE_SCN_LNK_COMDAT 0x00001000 /* Section contents comdat. */ +#define IMAGE_SCN_LNK_OTHER 0x00000100 /* Reserved. */ +#define IMAGE_SCN_LNK_INFO 0x00000200 /* Section contains comments or some other type of information. */ +#define IMAGE_SCN_LNK_REMOVE 0x00000800 /* Section contents will not become part of image. */ +#define IMAGE_SCN_LNK_COMDAT 0x00001000 /* Section contents comdat. */ #define IMAGE_SCN_MEM_FARDATA 0x00008000 @@ -77,7 +78,7 @@ #define IMAGE_SCN_MEM_LOCKED 0x00040000 #define IMAGE_SCN_MEM_PRELOAD 0x00080000 -/* Bit position in the s_flags field where the alignment values start. */ +/* Bit position in the s_flags field where the alignment values start. */ #define IMAGE_SCN_ALIGN_POWER_BIT_POS 20 #define IMAGE_SCN_ALIGN_POWER_BIT_MASK 0x00f00000 #define IMAGE_SCN_ALIGN_POWER_NUM(val) \ @@ -89,7 +90,7 @@ #define IMAGE_SCN_ALIGN_2BYTES IMAGE_SCN_ALIGN_POWER_CONST (1) #define IMAGE_SCN_ALIGN_4BYTES IMAGE_SCN_ALIGN_POWER_CONST (2) #define IMAGE_SCN_ALIGN_8BYTES IMAGE_SCN_ALIGN_POWER_CONST (3) -/* Default alignment if no others are specified. */ +/* Default alignment if no others are specified. */ #define IMAGE_SCN_ALIGN_16BYTES IMAGE_SCN_ALIGN_POWER_CONST (4) #define IMAGE_SCN_ALIGN_32BYTES IMAGE_SCN_ALIGN_POWER_CONST (5) #define IMAGE_SCN_ALIGN_64BYTES IMAGE_SCN_ALIGN_POWER_CONST (6) @@ -101,7 +102,7 @@ #define IMAGE_SCN_ALIGN_4096BYTES IMAGE_SCN_ALIGN_POWER_CONST (12) #define IMAGE_SCN_ALIGN_8192BYTES IMAGE_SCN_ALIGN_POWER_CONST (13) -/* Encode alignment power into IMAGE_SCN_ALIGN bits of s_flags */ +/* Encode alignment power into IMAGE_SCN_ALIGN bits of s_flags. */ #define COFF_ENCODE_ALIGNMENT(SECTION, ALIGNMENT_POWER) \ ((SECTION).s_flags |= IMAGE_SCN_ALIGN_POWER_CONST ((ALIGNMENT_POWER))) @@ -200,7 +201,7 @@ struct external_PEI_DOS_hdr struct external_PEI_IMAGE_hdr { - char nt_signature[4]; /* required NT signature, 0x4550. */ + char nt_signature[4]; /* Required NT signature, 0x4550. */ /* From standard header. */ char f_magic[2]; /* Magic number. */ @@ -239,7 +240,7 @@ struct external_PEI_filehdr /* Note: additional bytes may be inserted before the signature. Use the e_lfanew field to find the actual location of the NT signature. */ - char nt_signature[4]; /* required NT signature, 0x4550. */ + char nt_signature[4]; /* Required NT signature, 0x4550. */ /* From standard header. */ char f_magic[2]; /* Magic number. */ @@ -262,7 +263,7 @@ struct external_PEI_filehdr #endif /* COFF_IMAGE_WITH_PE */ -/* 32-bit PE a.out header: */ +/* 32-bit PE a.out header: */ typedef struct { @@ -422,14 +423,14 @@ union external_AUX_SYMBOL_EX struct { - char Length[4]; /* section length */ - char NumberOfRelocations[2]; /* # relocation entries */ - char NumberOfLinenumbers[2]; /* # line numbers */ - char Checksum[4]; /* section COMDAT checksum */ - char Number[2]; /* COMDAT associated section index */ - char Selection[1]; /* COMDAT selection number */ + char Length[4]; /* Section length. */ + char NumberOfRelocations[2];/* # relocation entries. */ + char NumberOfLinenumbers[2];/* # line numbers. */ + char Checksum[4]; /* Section COMDAT checksum. */ + char Number[2]; /* COMDAT associated section index. */ + char Selection[1]; /* COMDAT selection number. */ char bReserved[1]; - char HighNumber[2]; /* High bits of COMDAT associated sec. */ + char HighNumber[2]; /* High bits of COMDAT associated sec. */ char rgbReserved[2]; } Section; } ATTRIBUTE_PACKED; @@ -584,8 +585,9 @@ struct external_pex64_scope_entry (PEX64_OFFSET_TO_SCOPE_COUNT(COUNTOFUNWINDCODES) + \ PEX64_SCOPE_ENTRY_SIZE * (IDX)) -/* Extra structure used in debug directory */ -struct external_IMAGE_DEBUG_DIRECTORY { +/* Extra structure used in debug directory. */ +struct external_IMAGE_DEBUG_DIRECTORY +{ char Characteristics[4]; char TimeDateStamp[4]; char MajorVersion[2]; @@ -596,8 +598,8 @@ struct external_IMAGE_DEBUG_DIRECTORY { char PointerToRawData[4]; }; -/* Extra structures used in codeview debug record */ -/* This is not part of the PE specification */ +/* Extra structures used in codeview debug record. */ +/* This is not part of the PE specification. */ #define CVINFO_PDB70_CVSIGNATURE 0x53445352 // "RSDS" #define CVINFO_PDB20_CVSIGNATURE 0x3031424e // "NB10" diff --git a/ld/ChangeLog b/ld/ChangeLog index 5f7fed8..24f61abf 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -1,3 +1,8 @@ +2014-08-20 Daniel Micay <danielmicay@gmail.com> + + * emultempl/pep.em: Add --high-entropy-va switch. + * ld.texinfo: Document the --high-entropy-va switch. + 2014-08-20 Nick Clifton <nickc@redhat.com> * scripttempl/DWARF.sc: Add copyright notice. diff --git a/ld/emultempl/pep.em b/ld/emultempl/pep.em index 916a786..6d56bc3 100644 --- a/ld/emultempl/pep.em +++ b/ld/emultempl/pep.em @@ -237,6 +237,7 @@ enum options OPTION_LEADING_UNDERSCORE, OPTION_ENABLE_LONG_SECTION_NAMES, OPTION_DISABLE_LONG_SECTION_NAMES, + OPTION_HIGH_ENTROPY_VA, OPTION_DYNAMIC_BASE, OPTION_FORCE_INTEGRITY, OPTION_NX_COMPAT, @@ -314,6 +315,7 @@ gld${EMULATION_NAME}_add_options #endif {"enable-long-section-names", no_argument, NULL, OPTION_ENABLE_LONG_SECTION_NAMES}, {"disable-long-section-names", no_argument, NULL, OPTION_DISABLE_LONG_SECTION_NAMES}, + {"high-entropy-va", no_argument, NULL, OPTION_HIGH_ENTROPY_VA}, {"dynamicbase",no_argument, NULL, OPTION_DYNAMIC_BASE}, {"forceinteg", no_argument, NULL, OPTION_FORCE_INTEGRITY}, {"nxcompat", no_argument, NULL, OPTION_NX_COMPAT}, @@ -450,6 +452,8 @@ gld_${EMULATION_NAME}_list_options (FILE *file) executable image files\n")); fprintf (file, _(" --disable-long-section-names Never use long COFF section names, even\n\ in object files\n")); + fprintf (file, _(" --high-entropy-va Image is compatible with 64-bit address space\n\ + layout randomization (ASLR)\n")); fprintf (file, _(" --dynamicbase Image base address may be relocated using\n\ address space layout randomization (ASLR)\n")); fprintf (file, _(" --forceinteg Code integrity checks are enforced\n")); @@ -804,6 +808,9 @@ gld${EMULATION_NAME}_handle_option (int optc) pep_use_coff_long_section_names = 0; break; /* Get DLLCharacteristics bits */ + case OPTION_HIGH_ENTROPY_VA: + pe_dll_characteristics |= IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA; + break; case OPTION_DYNAMIC_BASE: pe_dll_characteristics |= IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE; break; diff --git a/ld/ld.texinfo b/ld/ld.texinfo index 718a7d0..e71be5e 100644 --- a/ld/ld.texinfo +++ b/ld/ld.texinfo @@ -2655,6 +2655,11 @@ The following options set flags in the @code{DllCharacteristics} field of the PE file header: [These options are specific to PE targeted ports of the linker] +@kindex --high-entropy-va +@item --high-entropy-va +Image is compatible with 64-bit address space layout randomization +(ASLR). + @kindex --dynamicbase @item --dynamicbase The image base address may be relocated using address space layout |