diff options
| -rw-r--r-- | gdb/ChangeLog | 8 | ||||
| -rw-r--r-- | gdb/Makefile.in | 2 | ||||
| -rw-r--r-- | gdb/dwarf2-frame.c | 146 |
3 files changed, 138 insertions, 18 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 837974a..f312013 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,11 @@ +2003-07-11 Richard Henderson <rth@redhat.com> + + * Makefile.in (dwarf2-frame.o): Add complaints_h. + * dwarf2-frame.c: Include complaints.h. + (decode_frame_entry_1): Rename from decode_frame_entry; tidy + variable initialization; return NULL on error. + (decode_frame_entry): New. + 2003-07-11 Andrew Cagney <cagney@redhat.com> * frame.h (frame_address_in_block): Delete declaration. diff --git a/gdb/Makefile.in b/gdb/Makefile.in index f3f0759..86cbc10 100644 --- a/gdb/Makefile.in +++ b/gdb/Makefile.in @@ -1680,7 +1680,7 @@ dwarf2loc.o: dwarf2loc.c $(defs_h) $(ui_out_h) $(value_h) $(frame_h) \ dwarf2-frame.o: $(defs_h) $(dwarf2expr_h) $(elf_dwarf2_h) $(frame_h) \ $(frame_base_h) $(frame_unwind_h) $(gdbcore_h) $(gdbtypes_h) \ $(symtab_h) $(objfiles_h) $(regcache_h) $(gdb_assert_h) \ - $(gdb_string_h) $(dwarf2_frame_h) + $(gdb_string_h) $(dwarf2_frame_h) $(complaints_h) dwarf2read.o: dwarf2read.c $(defs_h) $(bfd_h) $(symtab_h) $(gdbtypes_h) \ $(symfile_h) $(objfiles_h) $(elf_dwarf2_h) $(buildsym_h) \ $(demangle_h) $(expression_h) $(filenames_h) $(macrotab_h) \ diff --git a/gdb/dwarf2-frame.c b/gdb/dwarf2-frame.c index 999cef7..e0b1a05 100644 --- a/gdb/dwarf2-frame.c +++ b/gdb/dwarf2-frame.c @@ -36,6 +36,7 @@ #include "gdb_assert.h" #include "gdb_string.h" +#include "complaints.h" #include "dwarf2-frame.h" /* Call Frame Information (CFI). */ @@ -1058,35 +1059,44 @@ add_fde (struct comp_unit *unit, struct dwarf2_fde *fde) #define DW64_CIE_ID ~0 #endif -/* Read a CIE or FDE in BUF and decode it. */ +static char *decode_frame_entry (struct comp_unit *unit, char *start, + int eh_frame_p); +/* Decode the next CIE or FDE. Return NULL if invalid input, otherwise + the next byte to be processed. */ static char * -decode_frame_entry (struct comp_unit *unit, char *buf, int eh_frame_p) +decode_frame_entry_1 (struct comp_unit *unit, char *start, int eh_frame_p) { + char *buf; LONGEST length; unsigned int bytes_read; - int dwarf64_p = 0; - ULONGEST cie_id = DW_CIE_ID; + int dwarf64_p; + ULONGEST cie_id; ULONGEST cie_pointer; - char *start = buf; char *end; + buf = start; length = read_initial_length (unit->abfd, buf, &bytes_read); buf += bytes_read; end = buf + length; + /* Are we still within the section? */ + if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size) + return NULL; + if (length == 0) return end; - if (bytes_read == 12) - dwarf64_p = 1; + /* Distinguish between 32 and 64-bit encoded frame info. */ + dwarf64_p = (bytes_read == 12); - /* In a .eh_frame section, zero is used to distinguish CIEs from - FDEs. */ + /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */ if (eh_frame_p) cie_id = 0; else if (dwarf64_p) cie_id = DW64_CIE_ID; + else + cie_id = DW_CIE_ID; if (dwarf64_p) { @@ -1124,7 +1134,8 @@ decode_frame_entry (struct comp_unit *unit, char *buf, int eh_frame_p) cie->encoding = encoding_for_size (unit->addr_size); /* Check version number. */ - gdb_assert (read_1_byte (unit->abfd, buf) == DW_CIE_VERSION); + if (read_1_byte (unit->abfd, buf) != DW_CIE_VERSION) + return NULL; buf += 1; /* Interpret the interesting bits of the augmentation. */ @@ -1159,6 +1170,8 @@ decode_frame_entry (struct comp_unit *unit, char *buf, int eh_frame_p) length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read); buf += bytes_read; + if (buf > end) + return NULL; cie->initial_instructions = buf + length; augmentation++; } @@ -1211,16 +1224,20 @@ decode_frame_entry (struct comp_unit *unit, char *buf, int eh_frame_p) /* This is a FDE. */ struct dwarf2_fde *fde; + /* In an .eh_frame section, the CIE pointer is the delta between the + address within the FDE where the CIE pointer is stored and the + address of the CIE. Convert it to an offset into the .eh_frame + section. */ if (eh_frame_p) { - /* In an .eh_frame section, the CIE pointer is the delta - between the address within the FDE where the CIE pointer - is stored and the address of the CIE. Convert it to an - offset into the .eh_frame section. */ cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer; cie_pointer -= (dwarf64_p ? 8 : 4); } + /* In either case, validate the result is still within the section. */ + if (cie_pointer >= unit->dwarf_frame_size) + return NULL; + fde = (struct dwarf2_fde *) obstack_alloc (&unit->objfile->psymbol_obstack, sizeof (struct dwarf2_fde)); @@ -1252,6 +1269,8 @@ decode_frame_entry (struct comp_unit *unit, char *buf, int eh_frame_p) length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read); buf += bytes_read + length; + if (buf > end) + return NULL; } fde->instructions = buf; @@ -1262,6 +1281,99 @@ decode_frame_entry (struct comp_unit *unit, char *buf, int eh_frame_p) return end; } + +/* Read a CIE or FDE in BUF and decode it. */ +static char * +decode_frame_entry (struct comp_unit *unit, char *start, int eh_frame_p) +{ + enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE; + char *ret; + const char *msg; + ptrdiff_t start_offset; + + while (1) + { + ret = decode_frame_entry_1 (unit, start, eh_frame_p); + if (ret != NULL) + break; + + /* We have corrupt input data of some form. */ + + /* ??? Try, weakly, to work around compiler/assembler/linker bugs + and mismatches wrt padding and alignment of debug sections. */ + /* Note that there is no requirement in the standard for any + alignment at all in the frame unwind sections. Testing for + alignment before trying to interpret data would be incorrect. + + However, GCC traditionally arranged for frame sections to be + sized such that the FDE length and CIE fields happen to be + aligned (in theory, for performance). This, unfortunately, + was done with .align directives, which had the side effect of + forcing the section to be aligned by the linker. + + This becomes a problem when you have some other producer that + creates frame sections that are not as strictly aligned. That + produces a hole in the frame info that gets filled by the + linker with zeros. + + The GCC behaviour is arguably a bug, but it's effectively now + part of the ABI, so we're now stuck with it, at least at the + object file level. A smart linker may decide, in the process + of compressing duplicate CIE information, that it can rewrite + the entire output section without this extra padding. */ + + start_offset = start - unit->dwarf_frame_buffer; + if (workaround < ALIGN4 && (start_offset & 3) != 0) + { + start += 4 - (start_offset & 3); + workaround = ALIGN4; + continue; + } + if (workaround < ALIGN8 && (start_offset & 7) != 0) + { + start += 8 - (start_offset & 7); + workaround = ALIGN8; + continue; + } + + /* Nothing left to try. Arrange to return as if we've consumed + the entire input section. Hopefully we'll get valid info from + the other of .debug_frame/.eh_frame. */ + workaround = FAIL; + ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size; + break; + } + + switch (workaround) + { + case NONE: + break; + + case ALIGN4: + complaint (&symfile_complaints, + "Corrupt data in %s:%s; align 4 workaround apparently succeeded", + unit->dwarf_frame_section->owner->filename, + unit->dwarf_frame_section->name); + break; + + case ALIGN8: + complaint (&symfile_complaints, + "Corrupt data in %s:%s; align 8 workaround apparently succeeded", + unit->dwarf_frame_section->owner->filename, + unit->dwarf_frame_section->name); + break; + + default: + complaint (&symfile_complaints, + "Corrupt data in %s:%s", + unit->dwarf_frame_section->owner->filename, + unit->dwarf_frame_section->name); + break; + } + + return ret; +} + /* FIXME: kettenis/20030504: This still needs to be integrated with @@ -1307,9 +1419,9 @@ dwarf2_build_frame_info (struct objfile *objfile) unit.dwarf_frame_section = dwarf_eh_frame_section; /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base - that for the i386/amd64 target, which currently is the only - target in GCC that supports/uses the DW_EH_PE_datarel - encoding. */ + that for the i386/amd64 target, which currently is the only + target in GCC that supports/uses the DW_EH_PE_datarel + encoding. */ got = bfd_get_section_by_name (unit.abfd, ".got"); if (got) unit.dbase = got->vma; |