Add -OCFR-hacks option to help -OCFR

GJDuck · GJDuck · commit b724d05aff06 · 2022-12-07T18:06:31.000+08:00
This is for binaries such as Firefox that use
non-standard relocations (ELF hacks).
diff --git a/doc/e9patch.1 b/doc/e9patch.1
@@ -49,6 +49,11 @@ the rewritten binary much faster, but may introduce rewriting
 bugs if the built-in CRF analysis is inaccurate.
 .br
 Default: \fBfalse\fR (disabled)
+.IP "\fB\-OCFR-hacks\fR[=\fI\,false\/\fR]" 4
+Makes -OCFR even more conservative.  This may help some
+binaries that use non-standard relocations.
+.br
+Default: \fBfalse\fR (disabled)
 .IP "\fB\-Oepilogue\fR=\fI\,N\/\fR" 4
 Append a epilogue of up to N instructions to the end of each
 trampoline.  This may enhance \fB\-Opeephole\fR.
diff --git a/src/e9patch/e9CFR.cpp b/src/e9patch/e9CFR.cpp
@@ -404,7 +404,7 @@ void targetAnalysis(Binary *B)
             }
         }
     }
-    if (!pic)
+    if (!pic || option_OCFR_hacks)
     {
         // Non-PIC code pointers & jump tables
         for (unsigned i = 0; i < phnum; i++)
diff --git a/src/e9patch/e9patch.cpp b/src/e9patch/e9patch.cpp
@@ -48,6 +48,7 @@ bool option_tactic_T2          = true;
 bool option_tactic_T3          = true;
 bool option_tactic_backward_T3 = true;
 bool option_OCFR               = false;
+bool option_OCFR_hacks         = false;
 unsigned option_Oepilogue      = 0;
 unsigned option_Oepilogue_size = 64;
 bool option_Oorder             = false;
@@ -238,6 +239,11 @@ static void usage(FILE *stream, const char *progname)
         "\t\tbugs if the built-in CRF analysis is inaccurate.\n"
         "\t\tDefault: false (disabled)\n"
         "\n"
+        "\t-OCFR-hacks[=false]\n"
+        "\t\tMakes -OCFR even more conservative.  This may help some\n"
+        "\t\tbinaries that use non-standard relocations.\n"
+        "\t\tDefault: false (disabled)\n"
+        "\n"
         "\t-Oepilogue=N\n"
         "\t\tAppend a epilogue of up to N instructions to the end of each\n"
         "\t\ttrampoline.  This may enhance -Opeephole.\n"
@@ -401,6 +407,7 @@ enum Option
     OPTION_MEM_REBASE,
     OPTION_MEM_UB,
     OPTION_OCFR,
+    OPTION_OCFR_HACKS,
     OPTION_OEPILOGUE,
     OPTION_OEPILOGUE_SIZE,
     OPTION_OORDER,
@@ -435,6 +442,7 @@ void parseOptions(char * const argv[], bool api)
     static const struct option long_options[] =
     {
         {"OCFR",               opt_arg, nullptr, OPTION_OCFR},
+        {"OCFR-hacks",         opt_arg, nullptr, OPTION_OCFR_HACKS},
         {"Oepilogue",          req_arg, nullptr, OPTION_OEPILOGUE},
         {"Oepilogue-size",     req_arg, nullptr, OPTION_OEPILOGUE_SIZE},
         {"Oorder",             opt_arg, nullptr, OPTION_OORDER},
@@ -506,7 +514,10 @@ void parseOptions(char * const argv[], bool api)
                 option_input = optarg;
                 break;
             case OPTION_OCFR:
-                option_OCFR = (unsigned)parseBoolOptArg("-OCFR", optarg);
+                option_OCFR = parseBoolOptArg("-OCFR", optarg);
+                break;
+            case OPTION_OCFR_HACKS:
+                option_OCFR_hacks = parseBoolOptArg("-OCFR-hacks", optarg);
                 break;
             case OPTION_OEPILOGUE:
                 option_Oepilogue =
diff --git a/src/e9patch/e9patch.h b/src/e9patch/e9patch.h
@@ -593,6 +593,7 @@ extern bool option_is_tty;
 extern bool option_debug;
 extern bool option_batch;
 extern bool option_OCFR;
+extern bool option_OCFR_hacks;
 extern unsigned option_Oepilogue;
 extern unsigned option_Oepilogue_size;
 extern bool option_Oorder;

Original file line number	Diff line number	Diff line change
`@@ -404,7 +404,7 @@ void targetAnalysis(Binary *B)`
`404`	`404`	`}`
`405`	`405`	`}`
`406`	`406`	`}`
`407`		`- if (!pic)`
	`407`	`+ if (!pic \|\| option_OCFR_hacks)`
`408`	`408`	`{`
`409`	`409`	`// Non-PIC code pointers & jump tables`
`410`	`410`	`for (unsigned i = 0; i < phnum; i++)`