GNU and Oracle libelf implementations added support for section
compression, intended to reduce the size of DWARF debug info (which
might be an order of magnitude larger than the code).
There are two compressed ELF section formats:
1. Old GNU - sections are renmaed to start with 'z'. Section contains
a magic number, uncompressed size, and compressed data.
2. Oracle and New GNU - compressed sections use the SHF_COMPRESSED flag.
The compression header contains the compression type, uncompressed
size, and uncompressed alignment.
The second style is preferred and this change implements only that one.
Submitted by: Tiger Gao <tig@FreeBSDFoundation.org>
Reviewed by: markj
MFC after: 2 weeks
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D24566
gnu_debuglink external debug files will contain an .eh_frame section of
type SHT_NOBITS. libdwarf does not handle such sections (or rather, it
expects all debug sections to not have type SHT_NOBITS). Avoid loading
SHT_NOBITS sections, to be consistent with SGI libdwarf's handling of
this case.
PR: 239516
Diagnosed by: Paco Pascal <me@pacopascal.com>
Reviewed by: emaste (previous version)
Event: July 2020 Bugathon
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D25626
There is no reason for diep to ever be NULL, since in that case we would
simply be leaking memory.
CID: 1418801
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Previously objcopy (elfcopy) --add-sections inserted new sections before
.shstrtab, but omitted them if there was no .shstrtab.
Now, after processing existing sections add new sections if they were
not yet added.
PR: 241437
Reported by: arrowd
Submitted by: Tiger Gao <tig@FreeBSDFoundation.org>
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D23571
Previously _libelf_cvt_NOTE_tom (to host) returned false if a note's
namesz + descsz exceeded the buffer size, while _libelf_cvt_NOTE_tof
(to file) silently truncated. Return false in the latter case too.
Sponsored by: The FreeBSD Foundation
Previously corrupt note namesz or descsz (perhaps caused by readelf's
current lack of endian support for notes) resulted in a crash. Check
that namesz and descsz do not extend beyond the end of the buffer before
trying to access name and desc data.
Reported by: jhb
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
This will be used to tag binaries that require W+X mappings, in advance
of the ability to prevent W^X in mmap/mprotect.
There is still some discussion about the flag's name, but the ABI won't
change even if the name does (as kib pointed out in the review).
Reviewed by: csjp, kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D23909
From r349609 (PROTMAX_DISABLE) and r354790 (STKGAP_DISABLE). Commited
upstream (in a slightly different form) as r3831.
Sponsored by: The FreeBSD Foundation
Presumably a bool definition is obtained via header contamination on
FreeBSD-CURRENT. Found while trying to upstream FreeBSD addr2line
changes - the FreeBSD 11.2 CI build failed there.
Reported by: Cirrus-CI, upstream ELF Tool Chain
MFC with: r357844
Sponsored by: The FreeBSD Foundation
The caller of dump_object() is responsible for opening the file, let it
be responsible for closing too.
CID: 1411588
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
The callers only check whether the returned pointer is non-NULL, so this
was harmless in practice, but change the return value to guard against
the issue.
CID: 1411597
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
We should really create the output file in the same directory as the
destination file so that rename() works. This will be done in a future
change as part of some work to run in capability mode.
CID: 1262523
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
The code clearly meant to resize the buffer in the case where a section
was backed by multiple data descriptors.
In practice this shouldn't have been a problem since libelf would return
a single data descriptor for each section in a newly opened file.
CID: 1262522
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
All callers pass a non-NULL pointer, and otherwise it was possible to
leak memory if the abbrev was not added to a CU.
CID: 1193365
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
All callers of _dwarf_add_expr() and _dwarf_expr_into_block() pass a
non-NULL expr pointer, and these functions assume that expr is non-NULL
anyway.
CID: 1193305, 1193306
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Previously, addr2line would sequentially search all CUs for each input
address. For some uses, notably syzkaller's code coverage map generator,
this was extremely slow. Add a CU cache into which entries are added
following a successful lookup, and search the cache before falling back
to a scan. When translating a large number of addresses this yields
slightly better performance than GNU addr2line.
Garbage-collect an unused hash table which appears to have been intended
for the same purpose. A hash table doesn't seem particularly suitable
since each CU spans a range of addresses.
Submitted by: Tiger Gao <tig@freebsdfoundation.org>
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D23418
Summary: A follow-on to r276634, which added the VMX note to userland cores,
and r334538 for VSX notes.
Copied from note_type_linux_core().
Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D22404
Object files may specify insufficient alignment on certain sections, for
example due to a bug in NASM[1]. When we detect that case in elfcopy or
strip, emit a warning and increase the alignment to the minimum
required.
The NASM bug was fixed in 2015[2], but we might as well have this fixup
(and warning) in elfcopy in case we encounter such a file for any other
reason.
This might be reworked somewhat upstream - see ELF Tool Chain
ticket 485[3].
[1] https://bugzilla.nasm.us/show_bug.cgi?id=3392307
[2] 1f0cb0f2c1
[3] https://sourceforge.net/p/elftoolchain/tickets/485/
PR: 198611
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D2292
Calculate binary file offset using address field, bacause software know only offset to known data, not where to load segment.
With that patch, kernel .data section can have any alignment/offset - kernel boor fine.
PR: 235391
Reviewed by: markj
MFC after: 1 month
Differential Revision: D21827
Adjust argc and argv by optind before using them. This slightly
simplifies the code. No functional change intended.
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21079
The low fd limit used by poudriere exposed an odd failure mode in
cap_fileargs (used by readelf as of r350516). In particular, when
the limit was hit, both the main process and casper service would
block on their shared socket, waiting forever for the other to send a
message.
Reported by: zeising
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
