in MachOObjectFile::getSymbolByIndex() when a Mach-O file has
a symbol table load command but the number of symbols are zero.
The code in MachOObjectFile::symbol_begin_impl() should not be
assuming there is a symbol at index 0, in cases there is no symbol
table load command or the count of symbol is zero. So I also fixed
that. And needed to fix MachOObjectFile::symbol_end_impl() to
also do the same thing for no symbol table or one with zero entries.
The code in MachOObjectFile::getSymbolByIndex() should trigger
the report_fatal_error() for programmatic errors for any index when
there is no symbol table load command and not return the end iterator.
So also fixed that. Note there is no test case as this is a programmatic
error.
The test case using the file macho-invalid-bad-symbol-index has
a symbol table load command with its number of symbols (nsyms)
is zero. Which was incorrectly testing the bad triggering of the
report_fatal_error() in in MachOObjectFile::getSymbolByIndex().
This test case is an invalid Mach-O file but not for that reason.
It appears this Mach-O file use to have an nsyms value of 11,
and what makes this Mach-O file invalid is the counts and
indexes into the symbol table of the dynamic load command
are now invalid because the number of symbol table entries
(nsyms) is now zero. Which can be seen with the existing
llvm-obdump:
% llvm-objdump -private-headers macho-invalid-bad-symbol-index
…
Load command 4
cmd LC_SYMTAB
cmdsize 24
symoff 4216
nsyms 0
stroff 4392
strsize 144
Load command 5
cmd LC_DYSYMTAB
cmdsize 80
ilocalsym 0
nlocalsym 8 (past the end of the symbol table)
iextdefsym 8 (greater than the number of symbols)
nextdefsym 2 (past the end of the symbol table)
iundefsym 10 (greater than the number of symbols)
nundefsym 1 (past the end of the symbol table)
...
And the native darwin tools generates an error for this file:
% nm macho-invalid-bad-symbol-index
nm: object: macho-invalid-bad-symbol-index truncated or malformed object (ilocalsym plus nlocalsym in LC_DYSYMTAB load command extends past the end of the symbol table)
I added new checks for the indexes and sizes for these in the
constructor of MachOObjectFile. And added comments for what
would be a proper diagnostic messages.
And changed the test case using macho-invalid-bad-symbol-index
to test for the new error now produced.
Also added a test with a valid Mach-O file with a symbol table
load command where the number of symbols is zero that shows
the report_fatal_error() is not called.
llvm-svn: 258576
but to return object_error::parse_failed. Then made the code in llvm-nm
do for Mach-O files what is done in the darwin native tools which is to
print "bad string index" for bad string indexes. Updated the error message
in the llvm-objdump test, and added tests to show llvm-nm prints
"bad string index" and a test to print the actual bad string index value
which in this case is 0xfe000002 when printing the fields as raw hex.
llvm-svn: 258520
but to return object_error::parse_failed. Then made the code in llvm-nm
do for Mach-O files what is done in the darwin native tools which is to
print "(?,?)" or just "s" for bad section indexes. Also added a test to show
it prints the bad section index of "42" when printing the fields as raw hex.
llvm-svn: 258434
Report proper error code from MachOObjectFile constructor if we
can't parse another segment load command (we already return a proper
error if segment load command contents is suspicious).
llvm-svn: 239109
Summary:
Properly report the error in segment load commands from MachOObjectFile
constructor instead of crashing the program.
Adjust the test case accordingly.
Test Plan: regression test suite
Reviewers: rafael, filcab
Subscribers: llvm-commits
llvm-svn: 239081
Summary:
Currently all load commands are parsed in MachOObjectFile constructor.
If the next load command cannot be parsed, or if command size is too
small, properly report it through the error code and fail to construct
the object, instead of crashing the program.
Test Plan: regression test suite
Reviewers: rafael, filcab
Subscribers: llvm-commits
llvm-svn: 239080
Summary: Instead, properly report this error from MachOObjectFile constructor.
Test Plan: regression test suite
Reviewers: rafael
Subscribers: llvm-commits
llvm-svn: 239078
MachO and COFF quite reasonably only define the size for common symbols.
We used to try to figure out the "size" by computing the gap from one symbol to
the next.
This would not be correct in general, since a part of a section can belong to no
visible symbol (padding, private globals).
It was also really expensive, since we would walk every symbol to find the size
of one.
If a caller really wants this, it can sort all the symbols once and get all the
gaps ("size") in O(n log n) instead of O(n^2).
On MachO this also has the advantage of centralizing all the checks for an
invalid n_sect.
llvm-svn: 238028
Summary:
Shift an older “invalid file” test to get a consistent naming for these tests.
Bugs found by afl-fuzz
Reviewers: rafael
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D6945
llvm-svn: 226219
Kevin Enderby