Dwarf: fix parsing self-hosted debug info for stack traces

1 files changed, 13 insertions, 14 deletions

diff --git a/lib/std/debug/Dwarf.zig b/lib/std/debug/Dwarf.zig
index 7cce30df38..21d60214dd 100644
--- a/lib/std/debug/Dwarf.zig
+++ b/lib/std/debug/Dwarf.zig
@@ -279,10 +279,11 @@ pub const Die = struct {
         };
     }
 
-    fn getAttrRef(self: *const Die, id: u64) !u64 {
+    fn getAttrRef(self: *const Die, id: u64, unit_offset: u64, unit_len: u64) !u64 {
         const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
         return switch (form_value.*) {
-            .ref => |value| value,
+            .ref => |offset| if (offset < unit_len) unit_offset + offset else bad(),
+            .ref_addr => |addr| addr,
             else => bad(),
         };
     }
@@ -428,14 +429,14 @@ pub const ExceptionFrameHeader = struct {
         };
 
         const fde_entry_header = try EntryHeader.read(&eh_frame_fbr, if (eh_frame_len == null) ma else null, .eh_frame);
-        if (!self.isValidPtr(u8, @intFromPtr(&fde_entry_header.entry_bytes[fde_entry_header.entry_bytes.len - 1]), ma, eh_frame_len)) return bad();
+        if (fde_entry_header.entry_bytes.len > 0 and !self.isValidPtr(u8, @intFromPtr(&fde_entry_header.entry_bytes[fde_entry_header.entry_bytes.len - 1]), ma, eh_frame_len)) return bad();
         if (fde_entry_header.type != .fde) return bad();
 
         // CIEs always come before FDEs (the offset is a subtraction), so we can assume this memory is readable
         const cie_offset = fde_entry_header.type.fde;
         try eh_frame_fbr.seekTo(cie_offset);
         const cie_entry_header = try EntryHeader.read(&eh_frame_fbr, if (eh_frame_len == null) ma else null, .eh_frame);
-        if (!self.isValidPtr(u8, @intFromPtr(&cie_entry_header.entry_bytes[cie_entry_header.entry_bytes.len - 1]), ma, eh_frame_len)) return bad();
+        if (cie_entry_header.entry_bytes.len > 0 and !self.isValidPtr(u8, @intFromPtr(&cie_entry_header.entry_bytes[cie_entry_header.entry_bytes.len - 1]), ma, eh_frame_len)) return bad();
         if (cie_entry_header.type != .cie) return bad();
 
         cie.* = try CommonInformationEntry.parse(
@@ -942,13 +943,12 @@ fn scanAllFunctions(di: *Dwarf, allocator: Allocator) ScanError!void {
                                 defer fbr.pos = after_die_offset;
 
                                 // Follow the DIE it points to and repeat
-                                const ref_offset = try this_die_obj.getAttrRef(AT.abstract_origin);
-                                if (ref_offset > next_offset) return bad();
-                                try fbr.seekTo(this_unit_offset + ref_offset);
+                                const ref_offset = try this_die_obj.getAttrRef(AT.abstract_origin, this_unit_offset, next_offset);
+                                try fbr.seekTo(ref_offset);
                                 this_die_obj = (try parseDie(
                                     &fbr,
                                     attrs_bufs[2],
-                                    abbrev_table,
+                                    abbrev_table, // wrong abbrev table for different cu
                                     unit_header.format,
                                 )) orelse return bad();
                             } else if (this_die_obj.getAttr(AT.specification)) |_| {
@@ -956,13 +956,12 @@ fn scanAllFunctions(di: *Dwarf, allocator: Allocator) ScanError!void {
                                 defer fbr.pos = after_die_offset;
 
                                 // Follow the DIE it points to and repeat
-                                const ref_offset = try this_die_obj.getAttrRef(AT.specification);
-                                if (ref_offset > next_offset) return bad();
-                                try fbr.seekTo(this_unit_offset + ref_offset);
+                                const ref_offset = try this_die_obj.getAttrRef(AT.specification, this_unit_offset, next_offset);
+                                try fbr.seekTo(ref_offset);
                                 this_die_obj = (try parseDie(
                                     &fbr,
                                     attrs_bufs[2],
-                                    abbrev_table,
+                                    abbrev_table, // wrong abbrev table for different cu
                                     unit_header.format,
                                 )) orelse return bad();
                             } else {
@@ -1494,7 +1493,7 @@ fn runLineNumberProgram(d: *Dwarf, gpa: Allocator, compile_unit: *CompileUnit) !
         }
     } else {
         const FileEntFmt = struct {
-            content_type_code: u8,
+            content_type_code: u16,
             form_code: u16,
         };
         {
@@ -1539,7 +1538,7 @@ fn runLineNumberProgram(d: *Dwarf, gpa: Allocator, compile_unit: *CompileUnit) !
         if (file_name_entry_format_count > file_ent_fmt_buf.len) return bad();
         for (file_ent_fmt_buf[0..file_name_entry_format_count]) |*ent_fmt| {
             ent_fmt.* = .{
-                .content_type_code = try fbr.readUleb128(u8),
+                .content_type_code = try fbr.readUleb128(u16),
                 .form_code = try fbr.readUleb128(u16),
             };
         }