There are various places in the code that check whether mmapped structures
are correctly aligned (or ALLOW_UNALIGNED is set). Some of these checks
are asserts. Like the one in elf(32|64)_getshdr. We should not get into
that part of the code if the shdr scn structure was cached in elf_begin
because it was mmapped in and properly aligned.
These asserts could trigger because in elf_begin.c file_read_elf ()
all alignment checks were combined. So even though only one of the ehdr,
shdr or phdr structures were not properly aligned all structures would be
copied. Also the phdr structure was not even read in elf_begin, so the
alignment check was unnecessary.
This patch splits the alignment checks and reading of ehdr and shdr
structures into separate code paths. It also drops the phdr alignment
checks in elf_begin. Those phdr checks are done in elf(32|64)_getphdr
already.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
commit c57829 introduced a memory leak by passing the path string to
strsep. strsep will change the given pointer and set it to NULL eventually.
Causing the original pointer to leak. Fix by passing a copy of the pointer
to strsep.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
We define MODVERSION to make sure the libebl backend modules match the
elfutils build when we dlopen them. Using hostname and date makes it very
hard to create reproducable builds. Define them a little more reproducable
using LIBEBL_SUBDIR, eu_version and ac_cv_build.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
The -fsanitize=undefined check need to use AC_LINK_IFELSE to make sure
libubsan is installed. When doing undefined checking we should disable
ALLOW_UNALIGNED memory accesses to catch issues where we do unaligned
accesses by accident.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
core file data isn't guaranteed to be alligned properly. Use
read_(4|8)ubyte_unaligned_noncvt to read values, types and addresses.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
When a copy needs to be made of the shdrs, allocate with malloc and free
after conversion instead of calling alloca.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
When a copy needs to be made of the phdrs, allocate with malloc and free
after conversion instead of calling alloca.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
The number of entries in the index can be large, don't use alloca to
read in temporary data, use malloc (which is freed after out).
Signed-off-by: Mark Wielaard <mjw@redhat.com>
Without bunzip2 make check cannot be run. To generate all files in
maintainer-mode flex and bison are needed. Otherwise check that
libdw/known-dwarf.h is already generated.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
If we are going to dereference a pointer there should be at least enough
data to hold a pointer. Found by afl-fuzz.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
If we are going to dereference a pointer there should be at least enough
data to hold a pointer. Found by afl-fuzz.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
check_module is called from dwfl_module_relocate_address and from
dwfl_module_address_section. Both could take a NULL Dwfl_Module if
an earlier error had occured. Make check_module return immediately
indicating an issue in that case.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
All library code now builds with this warning and -Werror enabled.
Add exceptions for most of the src tools (ldgeneric, readelf, nm, size,
strip, elflint, findtextrel, elfcmp objdump, ranlib, ar and unstrip).
Signed-off-by: Mark Wielaard <mjw@redhat.com>
Limit stack usage of lines with MAX_STACK_LINES, files with MAX_STACK_LINES
and dirs with MAX_STACK_DIRS. Calculate number of dirs needed first, then
create dirarray directly, without needing the next field. Free not stack
allocated lines and files at the end.
Use preallocated stack arrays for all instead of calling alloca to help
compiler see actual stack usage.
The current stack allocation limits are 4096 lines, 1024 files in 256 dirs
per CU. For GCC 4.8 libstdc++.so has on average 512 lines per CU. With
these settings read_srclines uses max 228K of stack on x86_64.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
We cannot handle build-ids less than at least 3 or more than 64 bytes.
Very big build-ids, or very large debug search paths might have blown
up the stack.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
Don't stack allocate module name. Also fixes a latent bug (if the module
file didn't have a suffix - which is very unlikely) and an inefficiency.
We only need to substitue chars up to the suffix.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
Create a stack allocated array to hold locs. Allocate locs bigger than
the array with malloc and free them when done.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
For modules with lots of sections cache_sections could blow up the stack
theoretically. Don't use alloca, but use malloc with explicit free.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
Normally an NT_GNU_ABI_TAG is large, just 4 words (16 bytes).
Only use stack allocated conversion buf for small (max 16 words) notes.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
Help the compiler see we stack allocate a small array. Add assert to check
no machine prefix is ever larger than 16. Current maximum number is 7.
This prevents gcc warning about possible unbounded stack usage with
-Wstack-usage.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
The number of entries in the index can be large, don't use alloca to
read in temporary data, use malloc (and free after out).
Signed-off-by: Mark Wielaard <mjw@redhat.com>
This adds an option --pretty-print to eu-addr2line to show all information
on one line and all inlines on a line of their own. This mimics the same
option from binutils addr2line, but without the short option variant -p.
Since we already use -p to select the process.
Example output:
eu-addr2line --pretty-print -s -i -f -C -p$(pidof firefox) 0x00007f368c6f8915
mozilla::ReentrantMonitor::Wait(unsigned int) at ReentrantMonitor.h:92
(inlined by) mozilla::ReentrantMonitorAutoEnter::Wait(unsigned int) at ReentrantMonitor.h:190
A couple of tests were added to check the output matches that of
binutils addr2line.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
Makes the -C, --demangle option visible and implements it (ignoring the
demangle style argument). Adds a new test with sample output.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
We would sometimes interpret input addresses as decimal or octal.
That could be confusing and isn't what binutils addr2line does.
Be consistent and always treat input addresses as hex.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
This makes it clear that -j, --section=NAME is about how input is treated,
not how the output is formatted.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
This fixes an obscure SIGBUS error when using ELF_C_WRITE_MMAP on an ELF
file that needs extending when the underlying file system is (nearly) full.
Use posix_fallocate to make sure the file content is really there. Using
ftruncate might mean the file is extended, but space isn't allocated yet.
This might cause a SIGBUS once we write into the mmapped space and the disk
is full.
Using fallocate might fail on some file systems. posix_fallocate is
required to extend the file and allocate enough space even if the
underlying filesystem would normally return EOPNOTSUPP or the kernel
doesn't implement the fallocate syscall. Also posix_fallocate has been in
glibc since 2.1.94, while support for fallocate was only added in 2.10
and kernel 2.6.23.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
Now that we are -fsanitize=undefined clean make sure we keep it that way.
We do have to disable alignment checking. Because we might explicitly
use unaligned accesses (see ALLOW_UNALIGNED).
Rename DISTCHECK_CONFIGURE_FLAGS to AM_DISTCHECK_CONFIGURE_FLAGS, so the
user can override. And add --enable-sanitize-undefined.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
If phnum is zero make sure e_phoff is also zero and not some random value.
That would cause trouble in update_file. This could happen when ELF_F_LAYOUT
is set and the user copied over a ehdr from a bogus ELF file where the phdrs
are unreadable. In that case trying to write out the new ELF image would
crash trying to follow the bogus e_phdr value.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
There were various places where a bogus/unexpected input file would cause
eu-strip to crash. Also on an unexpected error eu-strip would leak the temp
debug file it was writing.
https://bugzilla.redhat.com/show_bug.cgi?id=1170810#c34
Signed-off-by: Mark Wielaard <mjw@redhat.com>
There were two issues with bogus sh_addralign values. First we would only
check the individual Elf_Data d_align values were powerof2. But not the
actual shdr addralign value. This would cause an issue if the shdr addralign
was bigger than all of the individual d_align values. Then we could write
out a bogus (! powerof2) shdr addralign value for the sections. Secondly
when reading in the Elf_Data we would set the d_align value to the value
of the shdr addralign value. But we would not check it was valid at all.
In practice there are ELF files with incorrect sh_addralign values (they
are a powerof2, but aren't aligned to the ELF image offset). We would try
to fix that up in elf_update by adding extra padding. But this could bloat
the ELF image a lot for large alignment values. So for too large alignments
that are bigger than the offset in the ELF file clamp them to the offset
value. This could lead us to reject to write out the data again when the
offset was not a powerof2. But this will only happen for aligment values
bigger than 64. Which are uncommon in practice.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
Creating phdr with more than PN_XNUM phnum requires a valid section zero
shdr to store the extended value. Make sure the shdrs are valid. Also fix
the error when count was too big to store by setting ELF_E_INVALID_INDEX
before failing.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
In order to provide better feedback to users, a distinction is made
between finding no dwarf info (E_NO_DWARF) and finding dwarf info but
which is compressed and failed to decompress (E_COMPRESSED_ERROR). This
can occur for example if elfutils was built without zlib support, or if
the compressed section is invalid.
Signed-off-by: Jonathan Lebon <jlebon@redhat.com>
Signed-off-by: Mark Wielaard <mjw@redhat.com>
To help legibility, we separate the section name matching from the
actual section reading. This also allows us to remove duplicate code in
cases of sections appearing twice or empty section data. There are no
changes in functionality. The indentation will be fixed in the next
commit, in the interest of keeping this commit easier to read.
Signed-off-by: Jonathan Lebon <jlebon@redhat.com>
Signed-off-by: Mark Wielaard <mjw@redhat.com>
We need to check the cuoff points to a real Dwarf_Die before trying to
intern the cu with tsearch. Otherwise bogus keys might end up in the
search tree with NULL cus. That will cause crashes in compare_cukey
during next insertion or deletion of cus. We also don't want to insert
the EOF marker and unconditionally tdestroy the lazy_cu_root. The EOF
could be caused by bad DWARF from a bogus agranges entry.
https://bugzilla.redhat.com/show_bug.cgi?id=1170810#c30
Signed-off-by: Mark Wielaard <mjw@redhat.com>
Mark Wielaard