Ticket #6271: elf-support-for-images-with-a-single-rwx-PT_LOAD-program-header-v4.patch

src/system/kernel/elf.cpp

@@ -1965 +1965 @@
     size_t reservedSize;
     status_t status;
     ssize_t length;
+    bool textSectionWritable = false;
+    int executableHeaderCount = 0;
 
     TRACE(("elf_load_kspace: entry path '%s'\n", path));
 
@@ -2066 +2068 @@
             B_PAGE_SIZE);
         if (end > reservedSize)
             reservedSize = end;
+
+        if (programHeaders[i].IsExecutable())
+            executableHeaderCount ++;
     }
 
     // Check whether the segments have an unreasonable amount of unused space
@@ -2105 +2110 @@
         }
 
         // we're here, so it must be a PT_LOAD segment
-        if (programHeaders[i].IsReadWrite()) {
+
+        // Usually add-ons have two PT_LOAD headers: one for .data one or .text.
+        // x86 and PPC may differ in permission bits for .data's PT_LOAD header
+        // x86 is usually RW, PPC is RWE
+
+        // Some add-ons may have .text and .data concatenated in a single
+        // PT_LOAD RWE header and we must map that to .text.
+        if (programHeaders[i].IsReadWrite() &&
+            (!programHeaders[i].IsExecutable() || executableHeaderCount > 1)) {
             // this is the writable segment
             if (image->data_region.size != 0) {
                 // we've already created this segment
@@ -2122 +2135 @@
             }
             region = &image->text_region;
 
+            // some programs may have .text and .data concatenated in a
+            // single PT_LOAD section which is readable/writable/executable
+            textSectionWritable = programHeaders[i].IsReadWrite();
             snprintf(regionName, B_OS_NAME_LENGTH, "%s_text", fileName);
         } else {
             dprintf("%s: weird program header flags 0x%lx\n", fileName,
@@ -2191 +2207 @@
         goto error5;
 
     // We needed to read in the contents of the "text" area, but
-    // now we can protect it read-only/execute
+    // now we can protect it read-only/execute, unless this is a
+    // special image with concatenated .text and .data, when it
+    // will also need write access.
     set_area_protection(image->text_region.id,
-        B_KERNEL_READ_AREA | B_KERNEL_EXECUTE_AREA);
+        B_KERNEL_READ_AREA | B_KERNEL_EXECUTE_AREA |
+        (textSectionWritable ? B_KERNEL_WRITE_AREA : 0));
 
     // There might be a hole between the two segments, and we don't need to
     // reserve this any longer

headers/private/system/elf32.h

@@ -367 +367 @@
 inline bool
 Elf32_Phdr::IsExecutable() const
 {
-    return (p_flags & PF_PROTECTION_MASK) == (PF_READ | PF_EXECUTE);
+    return (p_flags & PF_EXECUTE) != 0;
 }