From 1d8f5d30a92285fd4e7895a1d00587ac487412e3 Mon Sep 17 00:00:00 2001 From: Mark Wielaard Date: Tue, 30 Apr 2019 13:00:17 +0200 Subject: libelf: If xlate can only convert the ELF note header, just do that. When we started parsing new style ELF_T_NHDR8 notes we added extra checks on alignment and padding. When those failed we would stop converting and just return the rest of the ELF Note unconverted. In the case were we just had enough data for just the ELF Note header and the destionation and source weren't the same we would then accidentially throw away the Note header conversion we just did. Fix that by indicating we did correctly convert just the header. Adds testcase that compares parsing ELF notes with gelf_getnote and parsing the raw data by hand using elf32_xlatetom using just the Note header and ignoring the (raw) note data. Signed-off-by: Mark Wielaard --- tests/xlate_notes.c | 157 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 157 insertions(+) create mode 100644 tests/xlate_notes.c (limited to 'tests/xlate_notes.c') diff --git a/tests/xlate_notes.c b/tests/xlate_notes.c new file mode 100644 index 00000000..90a4ae27 --- /dev/null +++ b/tests/xlate_notes.c @@ -0,0 +1,157 @@ +/* Test program for extracting ELF Note headers and getting whole notes. + Copyright (C) 2019 Red Hat, Inc. + This file is part of elfutils. + + This file is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + elfutils is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +#ifdef HAVE_CONFIG_H +# include +#endif + +#include +#include +#include +#include +#include +#include +#include + +#include ELFUTILS_HEADER(elf) +#include + +int +main (int argc, char *argv[]) +{ + if (argc != 2) + { + printf ("No ELF file given as argument\n"); + exit (1); + } + + const char *fname = argv[1]; + + // Initialize libelf. + elf_version (EV_CURRENT); + + /* Read the ELF from disk now. */ + int fd = open (fname, O_RDONLY); + if (fd == -1) + { + printf ("cannot open '%s': %s\n", fname, strerror (errno)); + exit (1); + } + + Elf *elf = elf_begin (fd, ELF_C_READ, NULL); + if (elf == NULL) + { + printf ("cannot create ELF descriptor: %s\n", elf_errmsg (-1)); + exit (1); + } + + GElf_Ehdr ehdr; + if (gelf_getehdr (elf, &ehdr) == NULL) + { + printf ("cannot get Ehdr: %s\n", elf_errmsg (-1)); + exit (1); + } + + /* Search for all SHT_NOTE sections. */ + Elf_Scn *scn = NULL; + while ((scn = elf_nextscn (elf, scn)) != NULL) + { + /* Get the header. */ + GElf_Shdr shdr; + if (gelf_getshdr (scn, &shdr) == NULL) + { + printf ("couldn't get shdr: %s\n", elf_errmsg (-1)); + exit (1); + } + + if (shdr.sh_type == SHT_NOTE) + { + printf ("Notes in section %zd:\n", elf_ndxscn (scn)); + + Elf_Data *raw = elf_rawdata (scn, NULL); + if (raw == NULL) + { + printf ("couldn't get raw data: %s\n", elf_errmsg (-1)); + exit (1); + } + + Elf_Data *data = elf_getdata (scn, NULL); + if (data == NULL) + { + printf ("couldn't get data: %s\n", elf_errmsg (-1)); + exit (1); + } + + size_t off = 0; + size_t next; + GElf_Nhdr nhdr; + size_t n_off; + size_t d_off; + while ((next = gelf_getnote (data, off, &nhdr, &n_off, &d_off)) > 0) + { + /* Now just get the note header "raw" (don't + copy/translate the note data). This only handles + traditional GNU ELF Notes, so we still use the next + from gelf_getnote (padding is different for new style + ELF_T_NHDR8 notes). */ + Elf32_Nhdr nh; + Elf_Data src = + { + .d_version = EV_CURRENT, .d_type = ELF_T_NHDR, + .d_size = sizeof nh + }; + Elf_Data dst = src; + src.d_buf = raw->d_buf + off; + dst.d_buf = &nh; + + if (elf32_xlatetom (&dst, &src, ehdr.e_ident[EI_DATA]) == NULL) + { + printf ("couldn't xlate note: %s\n", elf_errmsg (-1)); + exit (1); + } + + printf ("type: %" PRId32 ",%" PRId32 + ", namesz: %" PRId32 ",%" PRId32 + ", descsz: %" PRId32 ",%" PRId32 "\n", + nhdr.n_type, nh.n_type, + nhdr.n_namesz, nh.n_namesz, + nhdr.n_descsz, nh.n_descsz); + + if (nhdr.n_type != nh.n_type + || nhdr.n_namesz != nh.n_namesz + || nhdr.n_descsz != nh.n_descsz) + { + printf ("Nhdrs not equal!\n"); + exit (1); + } + + off = next; + } + } + + } + + if (elf_end (elf) != 0) + { + printf ("failure in elf_end: %s\n", elf_errmsg (-1)); + exit (1); + } + + close (fd); + + return 0; +} -- cgit v1.2.3