diff options
Diffstat (limited to 'tests/fillfile.c')
| -rw-r--r-- | tests/fillfile.c | 448 |
1 files changed, 448 insertions, 0 deletions
diff --git a/tests/fillfile.c b/tests/fillfile.c new file mode 100644 index 00000000..915e249d --- /dev/null +++ b/tests/fillfile.c @@ -0,0 +1,448 @@ +/* Test program for changing data in one section (but not others) with gaps. + Copyright (C) 2017 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 <http://www.gnu.org/licenses/>. */ + + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include <errno.h> +#include <fcntl.h> +#include <inttypes.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include ELFUTILS_HEADER(elf) +#include <gelf.h> + + +/* Index of last string added. Returned by add_string (). */ +static size_t stridx = 0; + +/* Adds a string and returns the offset in the section. */ +static size_t +add_strtab_entry (Elf_Scn *strtab, const char *str) +{ + size_t lastidx = stridx; + size_t size = strlen (str) + 1; + + Elf_Data *data = elf_newdata (strtab); + if (data == NULL) + { + printf ("cannot create data SHSTRTAB section: %s\n", elf_errmsg (-1)); + exit (1); + } + + data->d_buf = (char *) str; /* Discards const, but we will not change. */ + data->d_type = ELF_T_BYTE; + data->d_size = size; + data->d_align = 1; + data->d_version = EV_CURRENT; + + stridx += size; + printf ("add_string: '%s', stridx: %zd, lastidx: %zd\n", + str, stridx, lastidx); + return lastidx; +} + +static Elf_Scn * +create_strtab (Elf *elf) +{ + // Create strtab section. + Elf_Scn *scn = elf_newscn (elf); + if (scn == NULL) + { + printf ("cannot create strings section: %s\n", elf_errmsg (-1)); + exit (1); + } + + // Add an empty string to the table as NUL entry for section zero. + add_strtab_entry (scn, ""); + + GElf_Shdr shdr_mem; + GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); + if (shdr == NULL) + { + printf ("cannot get header for new strtab section: %s\n", + elf_errmsg (-1)); + exit (1); + } + + shdr->sh_type = SHT_STRTAB; + shdr->sh_flags = 0; + shdr->sh_addr = 0; + shdr->sh_link = SHN_UNDEF; + shdr->sh_info = SHN_UNDEF; + shdr->sh_addralign = 1; + shdr->sh_entsize = 0; + shdr->sh_name = add_strtab_entry (scn, ".strtab"); + + // We have to store the section strtab index in the ELF header. + // So sections have actual names. + GElf_Ehdr ehdr_mem; + GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem); + if (ehdr == NULL) + { + printf ("cannot get ELF header: %s\n", elf_errmsg (-1)); + exit (1); + } + + int ndx = elf_ndxscn (scn); + ehdr->e_shstrndx = ndx; + + if (gelf_update_ehdr (elf, ehdr) == 0) + { + printf ("cannot update ELF header: %s\n", elf_errmsg (-1)); + exit (1); + } + + // Finished strtab section, update the header. + if (gelf_update_shdr (scn, shdr) == 0) + { + printf ("cannot update STRTAB section header: %s\n", elf_errmsg (-1)); + exit (1); + } + + return scn; +} + +static char sec_data[] = { 1, 2, 3, 4, 5 }; +static char new_data[] = { 5, 4, 3, 2, 1 }; + +static void +add_data_section (Elf *elf, Elf_Scn *strtab, const char *sname) +{ + printf ("Add data section %s\n", sname); + Elf_Scn *scn = elf_newscn (elf); + if (scn == NULL) + { + printf ("cannot create strings section: %s\n", elf_errmsg (-1)); + exit (1); + } + + GElf_Shdr shdr_mem; + GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); + if (shdr == NULL) + { + printf ("cannot get header for new %s section: %s\n", + sname, elf_errmsg (-1)); + exit (1); + } + + shdr->sh_type = SHT_PROGBITS; + shdr->sh_flags = 0; + shdr->sh_addr = 0; + shdr->sh_link = SHN_UNDEF; + shdr->sh_info = SHN_UNDEF; + shdr->sh_addralign = 128; // Large alignment to force gap between sections. + shdr->sh_entsize = 1; + shdr->sh_name = add_strtab_entry (strtab, sname); + + if (gelf_update_shdr (scn, shdr) == 0) + { + printf ("cannot update %s section header: %s\n", sname, elf_errmsg (-1)); + exit (1); + } + + /* Add some data, but less than alignment. */ + Elf_Data *data = elf_newdata (scn); + if (data == NULL) + { + printf ("cannot update %s section header: %s\n", sname, elf_errmsg (-1)); + exit (1); + } + data->d_buf = sec_data; + data->d_size = 5; +} + +static void +check_data (const char *sname, Elf_Data *data, char *buf) +{ + printf ("check data %s [", sname); + for (int i = 0; i < 5; i++) + printf ("%d%s", buf[i], i < 4 ? "," : ""); + printf ("]\n"); + if (data == NULL || data->d_buf == NULL) + { + printf ("No data in section %s\n", sname); + exit (1); + } + + if (data->d_size != 5 || memcmp (data->d_buf, buf, 5) != 0) + { + printf ("Wrong data in section %s [", sname); + for (size_t i = 0; i < data->d_size; i++) + printf ("%d%s", ((char *)data->d_buf)[i], + i < data->d_size - 1 ? "," : ""); + printf ("]\n"); + exit(1); + } +} + +static void +check_elf (const char *fname, int class, int use_mmap) +{ + printf ("\nfname: %s\n", fname); + stridx = 0; // Reset strtab strings index + + int fd = open (fname, O_RDWR | O_CREAT | O_TRUNC, 0666); + if (fd == -1) + { + printf ("cannot open `%s': %s\n", fname, strerror (errno)); + exit (1); + } + + Elf *elf = elf_begin (fd, use_mmap ? ELF_C_WRITE_MMAP : ELF_C_WRITE, NULL); + if (elf == NULL) + { + printf ("cannot create ELF descriptor: %s\n", elf_errmsg (-1)); + exit (1); + } + + // Create an ELF header. + if (gelf_newehdr (elf, class) == 0) + { + printf ("cannot create ELF header: %s\n", elf_errmsg (-1)); + exit (1); + } + + GElf_Ehdr ehdr_mem; + GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem); + if (ehdr == NULL) + { + printf ("cannot get ELF header: %s\n", elf_errmsg (-1)); + exit (1); + } + + // Initialize header. + ehdr->e_ident[EI_DATA] = class == ELFCLASS64 ? ELFDATA2LSB : ELFDATA2MSB; + ehdr->e_ident[EI_OSABI] = ELFOSABI_GNU; + ehdr->e_type = ET_NONE; + ehdr->e_machine = EM_X86_64; + ehdr->e_version = EV_CURRENT; + + if (gelf_update_ehdr (elf, ehdr) == 0) + { + printf ("cannot update ELF header: %s\n", elf_errmsg (-1)); + exit (1); + } + + Elf_Scn *strtab = create_strtab (elf); + add_data_section (elf, strtab, ".data1"); + add_data_section (elf, strtab, ".data2"); + add_data_section (elf, strtab, ".data3"); + add_data_section (elf, strtab, ".data4"); + + // Write everything to disk. + if (elf_update (elf, ELF_C_WRITE) < 0) + { + printf ("failure in elf_update(WRITE): %s\n", elf_errmsg (-1)); + exit (1); + } + + if (elf_end (elf) != 0) + { + printf ("failure in elf_end: %s\n", elf_errmsg (-1)); + exit (1); + } + + close (fd); + + /* Reread the ELF from disk now. */ + printf ("Rereading %s\n", fname); + fd = open (fname, O_RDWR, 0666); + if (fd == -1) + { + printf ("cannot (re)open `%s': %s\n", fname, strerror (errno)); + exit (1); + } + + elf = elf_begin (fd, use_mmap ? ELF_C_RDWR_MMAP : ELF_C_RDWR, NULL); + if (elf == NULL) + { + printf ("cannot create ELF descriptor read-only: %s\n", elf_errmsg (-1)); + exit (1); + } + + /* We are going to change some data (in-place), but want the layout + to stay exactly the same. */ + elf_flagelf (elf, ELF_C_SET, ELF_F_LAYOUT); + + size_t shdrstrndx; + if (elf_getshdrstrndx (elf, &shdrstrndx) != 0) + { + printf ("cannot get shdr str ndx\n"); + exit (1); + } + printf ("shdrstrndx: %zd\n", shdrstrndx); + + // Get third data section and change it. + Elf_Scn *checkscn = NULL; + Elf_Scn *scn = elf_nextscn (elf, NULL); + while (scn != NULL) + { + GElf_Shdr shdr_mem; + GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); + if (shdr == NULL) + { + printf ("cannot get header for section: %s\n", elf_errmsg (-1)); + exit (1); + } + const char *sname = elf_strptr (elf, shdrstrndx, shdr->sh_name); + if (sname != NULL && strcmp (".data3", sname) == 0) + checkscn = scn; + + // Get all data, but don't really use it + // (this triggered the original bug). + Elf_Data *data = elf_getdata (scn, NULL); + if (data != NULL && data->d_buf != NULL && data->d_size == 0) + { + printf ("Bad data...n"); + exit (1); + } + scn = elf_nextscn (elf, scn); + } + + if (checkscn == NULL) + { + printf ("ELF file doesn't have a .data3 section\n"); + exit (1); + } + + Elf_Data *data = elf_getdata (checkscn, NULL); + check_data (".data3", data, sec_data); + memcpy (data->d_buf, new_data, 5); + elf_flagdata (data, ELF_C_SET, ELF_F_DIRTY); + + // Write everything to disk. + if (elf_update (elf, ELF_C_WRITE) < 0) + { + printf ("failure in elf_update(WRITE): %s\n", elf_errmsg (-1)); + exit (1); + } + + if (elf_end (elf) != 0) + { + printf ("failure in elf_end: %s\n", elf_errmsg (-1)); + exit (1); + } + + close (fd); + + // And read it in one last time. + printf ("Rereading %s again\n", fname); + fd = open (fname, O_RDONLY, 0666); + if (fd == -1) + { + printf ("cannot open `%s' read-only: %s\n", fname, strerror (errno)); + exit (1); + } + + elf = elf_begin (fd, use_mmap ? ELF_C_READ_MMAP : ELF_C_READ, NULL); + if (elf == NULL) + { + printf ("cannot create ELF descriptor read-only: %s\n", elf_errmsg (-1)); + exit (1); + } + + // Get all .data sections and check them. + Elf_Scn *scn1 = NULL; + Elf_Scn *scn2 = NULL; + Elf_Scn *scn3 = NULL; + Elf_Scn *scn4 = NULL; + scn = elf_nextscn (elf, NULL); + while (scn != NULL) + { + GElf_Shdr shdr_mem; + GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); + if (shdr == NULL) + { + printf ("cannot get header for section: %s\n", elf_errmsg (-1)); + exit (1); + } + const char *sname = elf_strptr (elf, shdrstrndx, shdr->sh_name); + if (sname != NULL && strcmp (".data1", sname) == 0) + scn1 = scn; + else if (sname != NULL && strcmp (".data2", sname) == 0) + scn2 = scn; + else if (sname != NULL && strcmp (".data3", sname) == 0) + scn3 = scn; + else if (sname != NULL && strcmp (".data4", sname) == 0) + scn4 = scn; + scn = elf_nextscn (elf, scn); + } + + if (scn1 == NULL) + { + printf ("ELF file doesn't have a .data1 section\n"); + exit (1); + } + data = elf_getdata (scn1, NULL); + check_data (".data1", data, sec_data); + + if (scn2 == NULL) + { + printf ("ELF file doesn't have a .data2 section\n"); + exit (1); + } + data = elf_getdata (scn2, NULL); + check_data (".data2", data, sec_data); + + if (scn3 == NULL) + { + printf ("ELF file doesn't have a .data3 section\n"); + exit (1); + } + data = elf_getdata (scn3, NULL); + check_data (".data3", data, new_data); + + if (scn4 == NULL) + { + printf ("ELF file doesn't have a .data4 section\n"); + exit (1); + } + data = elf_getdata (scn4, NULL); + check_data (".data4", data, sec_data); + + if (elf_end (elf) != 0) + { + printf ("failure in elf_end: %s\n", elf_errmsg (-1)); + exit (1); + } + + close (fd); + + unlink (fname); +} + +int +main (int argc __attribute__ ((unused)), + char *argv[] __attribute__ ((unused))) +{ + elf_version (EV_CURRENT); + + elf_fill (0xA); + + check_elf ("fill.elf.32", ELFCLASS32, 0); + check_elf ("fill.elf.32.mmap", ELFCLASS32, 1); + check_elf ("fill.elf.64", ELFCLASS64, 0); + check_elf ("fill.elf.64.mmap", ELFCLASS64, 1); + + return 0; +} |