Merge pull request #24628 from medhefgo/boot-sections

boot: Try to detect overlapping PE sections

src/boot/efi/meson.build

@@ -199,9 +199,12 @@ efi_cflags = [
         ]
 )
 
-# On some distros, sd-boot/-stub may trigger some bug somewhere that will cause
-# kernel execution to fail. The cause seems to be purely based on code size and
-# always compiling with at least -O1 will work around that.
+# Our code size has increased enough to possibly create overlapping PE sections
+# at sd-stub runtime, which will often enough prevent the image from booting.
+# This only happens because the usual instructions for assembling a unified
+# kernel image contain hardcoded addresses for section VMAs added in. Until a
+# proper solution is in place, we can at least compile with as least -O1 to
+# reduce the likelyhood of this happening.
 # https://github.com/systemd/systemd/issues/24202
 efi_cflags += '-O1'
 

src/boot/efi/pe.c

@@ -142,25 +142,31 @@ static void locate_sections(
                 const PeSectionHeader section_table[],
                 UINTN n_table,
                 const char * const sections[],
-                UINTN *addrs,
                 UINTN *offsets,
-                UINTN *sizes) {
+                UINTN *sizes,
+                bool in_memory) {
 
         assert(section_table);
         assert(sections);
+        assert(offsets);
         assert(sizes);
 
+        size_t prev_section_addr = 0;
+
         for (UINTN i = 0; i < n_table; i++) {
                 const PeSectionHeader *sect = section_table + i;
 
+                if (in_memory) {
+                        if (prev_section_addr > sect->VirtualAddress)
+                                log_error_stall(u"Overlapping PE sections detected. Boot may fail due to image memory corruption!");
+                        prev_section_addr = sect->VirtualAddress + sect->VirtualSize;
+                }
+
                 for (UINTN j = 0; sections[j]; j++) {
                         if (memcmp(sect->Name, sections[j], strlen8(sections[j])) != 0)
                                 continue;
 
-                        if (addrs)
-                                addrs[j] = sect->VirtualAddress;
-                        if (offsets)
-                                offsets[j] = sect->PointerToRawData;
+                        offsets[j] = in_memory ? sect->VirtualAddress : sect->PointerToRawData;
                         sizes[j] = sect->VirtualSize;
                 }
         }
@@ -178,8 +184,8 @@ static uint32_t get_compatibility_entry_address(const DosFileHeader *dos, const
                         pe->FileHeader.NumberOfSections,
                         sections,
                         &addr,
-                        NULL,
-                        &size);
+                        &size,
+                        /*in_memory=*/true);
 
         if (size == 0)
                 return 0;
@@ -274,8 +280,8 @@ EFI_STATUS pe_memory_locate_sections(const void *base, const char * const sectio
                         pe->FileHeader.NumberOfSections,
                         sections,
                         addrs,
-                        NULL,
-                        sizes);
+                        sizes,
+                        /*in_memory=*/true);
 
         return EFI_SUCCESS;
 }
@@ -338,7 +344,7 @@ EFI_STATUS pe_file_locate_sections(
                 return EFI_LOAD_ERROR;
 
         locate_sections(section_table, pe.FileHeader.NumberOfSections,
-                        sections, NULL, offsets, sizes);
+                        sections, offsets, sizes, /*in_memory=*/false);
 
         return EFI_SUCCESS;
 }