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Index: usr.bin/ldd/Makefile
===================================================================
--- usr.bin/ldd/Makefile
+++ usr.bin/ldd/Makefile
@@ -3,4 +3,6 @@
PROG?= ldd
SRCS= ldd.c
+LIBADD= elf
+
.include <bsd.prog.mk>
Index: usr.bin/ldd/ldd.c
===================================================================
--- usr.bin/ldd/ldd.c
+++ usr.bin/ldd/ldd.c
@@ -33,6 +33,7 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
+#include <sys/param.h>
#include <sys/wait.h>
#include <machine/elf.h>
@@ -43,6 +44,9 @@
#include <err.h>
#include <errno.h>
#include <fcntl.h>
+#include <gelf.h>
+#include <libelf.h>
+#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -259,179 +263,182 @@
exit(1);
}
+static bool
+is_pie(const char *fname, Elf *elf)
+{
+ GElf_Shdr shdr;
+ GElf_Dyn dyn;
+ Elf_Scn *scn;
+ Elf_Data *d;
+ u_int i;
+
+ scn = NULL;
+ while ((scn = elf_nextscn(elf, scn)) != NULL) {
+ if (gelf_getshdr(scn, &shdr) == NULL) {
+ warnx("%s: %s", fname, elf_errmsg(0));
+ return (false);
+ }
+
+ if (shdr.sh_type != SHT_DYNAMIC)
+ continue;
+
+ d = elf_getdata(scn, NULL);
+ if (d == NULL)
+ continue;
+
+ for (i = 0; i < shdr.sh_size / shdr.sh_entsize; i++) {
+ if (gelf_getdyn(d, i, &dyn) == NULL) {
+ warnx("%s: %s", fname, elf_errmsg(0));
+ break;
+ }
+
+ if (dyn.d_tag != DT_FLAGS_1)
+ continue;
+
+ return ((dyn.d_un.d_val & DF_1_PIE) != 0);
+ }
+ }
+
+ return (false);
+}
+
+static bool
+check_notes(const char *buf, size_t len)
+{
+ const Elf_Note *note;
+ const char *name;
+ size_t namesz, descsz;
+
+ for (;;) {
+ if (len < sizeof(*note))
+ return (false);
+ note = (const void *)buf;
+ buf += sizeof(*note);
+ len -= sizeof(*note);
+
+ namesz = roundup2(note->n_namesz, 4);
+ descsz = roundup2(note->n_descsz, 4);
+ if (len < namesz + descsz)
+ return (false);
+
+ name = buf;
+ if (strncmp(name, "FreeBSD", namesz) == 0 &&
+ note->n_type == NT_FREEBSD_ABI_TAG)
+ return (true);
+
+ buf += namesz + descsz;
+ len -= namesz + descsz;
+ }
+
+ return (false);
+}
+
+static bool
+is_freebsd_elf(const char *fname, Elf *elf, GElf_Ehdr *ehdr)
+{
+ GElf_Shdr shdr;
+ Elf_Scn *scn;
+ Elf_Data *d;
+
+ switch (ehdr->e_ident[EI_OSABI]) {
+ case ELFOSABI_FREEBSD:
+ return (true);
+ case ELFOSABI_NONE:
+ break;
+ default:
+ return (false);
+ }
+
+ scn = NULL;
+ while ((scn = elf_nextscn(elf, scn)) != NULL) {
+ if (gelf_getshdr(scn, &shdr) == NULL) {
+ warnx("%s: %s", fname, elf_errmsg(0));
+ return (false);
+ }
+
+ if (shdr.sh_type != SHT_NOTE)
+ continue;
+
+ d = elf_getdata(scn, NULL);
+ if (d == NULL)
+ continue;
+
+ if (check_notes(d->d_buf, d->d_size))
+ return (true);
+ }
+
+ return (false);
+}
+
static int
is_executable(const char *fname, int fd, int *is_shlib, int *type)
{
- union {
-#if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED)
- Elf32_Ehdr elf32;
-#endif
- Elf_Ehdr elf;
- } hdr;
- Elf_Phdr phdr, dynphdr;
- Elf_Dyn *dynp;
- void *dyndata;
-#if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED)
- Elf32_Phdr phdr32, dynphdr32;
- Elf32_Dyn *dynp32;
-#endif
- int df1pie, dynamic, i, n;
+ Elf *elf;
+ GElf_Ehdr ehdr;
+ GElf_Phdr phdr;
+ bool dynamic;
+ int i;
*is_shlib = 0;
*type = TYPE_UNKNOWN;
- df1pie = 0;
+ dynamic = false;
- if ((n = read(fd, &hdr, sizeof(hdr))) == -1) {
- warn("%s: can't read program header", fname);
+ if (elf_version(EV_CURRENT) == EV_NONE) {
+ warnx("unsupported libelf");
+ return (0);
+ }
+ elf = elf_begin(fd, ELF_C_READ, NULL);
+ if (elf == NULL) {
+ warnx("%s: %s", fname, elf_errmsg(0));
+ return (0);
+ }
+ if (elf_kind(elf) != ELF_K_ELF) {
+ elf_end(elf);
+ warnx("%s: not a dynamic ELF executable", fname);
+ return (0);
+ }
+ if (gelf_getehdr(elf, &ehdr) == NULL) {
+ warnx("%s: %s", fname, elf_errmsg(0));
+ elf_end(elf);
return (0);
}
+ *type = TYPE_ELF;
#if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED)
- if ((size_t)n >= sizeof(hdr.elf32) && IS_ELF(hdr.elf32) &&
- hdr.elf32.e_ident[EI_CLASS] == ELFCLASS32) {
- /* Handle 32 bit ELF objects */
-
- dynamic = 0;
+ if (gelf_getclass(elf) == ELFCLASS32) {
*type = TYPE_ELF32;
-
- if (lseek(fd, hdr.elf32.e_phoff, SEEK_SET) == -1) {
- warnx("%s: header too short", fname);
- return (0);
- }
- for (i = 0; i < hdr.elf32.e_phnum; i++) {
- if (read(fd, &phdr32, hdr.elf32.e_phentsize) !=
- sizeof(phdr32)) {
- warnx("%s: can't read program header", fname);
- return (0);
- }
- if (phdr32.p_type == PT_DYNAMIC) {
- dynamic = 1;
- dynphdr32 = phdr32;
- break;
- }
- }
-
- if (!dynamic) {
- warnx("%s: not a dynamic ELF executable", fname);
- return (0);
- }
-
- if (hdr.elf32.e_type == ET_DYN) {
- if (lseek(fd, dynphdr32.p_offset, SEEK_SET) == -1) {
- warnx("%s: dynamic segment out of range",
- fname);
- return (0);
- }
- dyndata = malloc(dynphdr32.p_filesz);
- if (dyndata == NULL) {
- warn("malloc");
- return (0);
- }
- if (read(fd, dyndata, dynphdr32.p_filesz) !=
- (ssize_t)dynphdr32.p_filesz) {
- free(dyndata);
- warnx("%s: can't read dynamic segment", fname);
- return (0);
- }
- for (dynp32 = dyndata; dynp32->d_tag != DT_NULL;
- dynp32++) {
- if (dynp32->d_tag != DT_FLAGS_1)
- continue;
- df1pie = (dynp32->d_un.d_val & DF_1_PIE) != 0;
- break;
- }
- free(dyndata);
-
- if (hdr.elf32.e_ident[EI_OSABI] == ELFOSABI_FREEBSD) {
- if (!df1pie)
- *is_shlib = 1;
- return (1);
- }
- warnx("%s: not a FreeBSD ELF shared object", fname);
- return (0);
- }
-
- return (1);
}
#endif
- if ((size_t)n >= sizeof(hdr.elf) && IS_ELF(hdr.elf) &&
- hdr.elf.e_ident[EI_CLASS] == ELF_TARG_CLASS) {
- /* Handle default ELF objects on this architecture */
-
- dynamic = 0;
- *type = TYPE_ELF;
-
- if (lseek(fd, hdr.elf.e_phoff, SEEK_SET) == -1) {
- warnx("%s: header too short", fname);
+ for (i = 0; i < ehdr.e_phnum; i++) {
+ if (gelf_getphdr(elf, i, &phdr) == NULL) {
+ warnx("%s: %s", fname, elf_errmsg(0));
+ elf_end(elf);
return (0);
}
- for (i = 0; i < hdr.elf.e_phnum; i++) {
- if (read(fd, &phdr, hdr.elf.e_phentsize)
- != sizeof(phdr)) {
- warnx("%s: can't read program header", fname);
- return (0);
- }
- if (phdr.p_type == PT_DYNAMIC) {
- dynamic = 1;
- dynphdr = phdr;
- break;
- }
+ switch (phdr.p_type) {
+ case PT_DYNAMIC:
+ dynamic = true;
+ break;
}
+ }
- if (!dynamic) {
- warnx("%s: not a dynamic ELF executable", fname);
- return (0);
- }
+ if (!dynamic) {
+ elf_end(elf);
+ warnx("%s: not a dynamic ELF executable", fname);
+ return (0);
+ }
- if (hdr.elf.e_type == ET_DYN) {
- if (lseek(fd, dynphdr.p_offset, SEEK_SET) == -1) {
- warnx("%s: dynamic segment out of range",
- fname);
- return (0);
- }
- dyndata = malloc(dynphdr.p_filesz);
- if (dyndata == NULL) {
- warn("malloc");
- return (0);
- }
- if (read(fd, dyndata, dynphdr.p_filesz) !=
- (ssize_t)dynphdr.p_filesz) {
- free(dyndata);
- warnx("%s: can't read dynamic segment", fname);
- return (0);
- }
- for (dynp = dyndata; dynp->d_tag != DT_NULL; dynp++) {
- if (dynp->d_tag != DT_FLAGS_1)
- continue;
- df1pie = (dynp->d_un.d_val & DF_1_PIE) != 0;
- break;
- }
- free(dyndata);
+ if (ehdr.e_type == ET_DYN && !is_pie(fname, elf)) {
+ *is_shlib = 1;
- switch (hdr.elf.e_ident[EI_OSABI]) {
- case ELFOSABI_FREEBSD:
- if (!df1pie)
- *is_shlib = 1;
- return (1);
-#ifdef __ARM_EABI__
- case ELFOSABI_NONE:
- if (hdr.elf.e_machine != EM_ARM)
- break;
- if (EF_ARM_EABI_VERSION(hdr.elf.e_flags) <
- EF_ARM_EABI_FREEBSD_MIN)
- break;
- *is_shlib = 1;
- return (1);
-#endif
- }
+ if (!is_freebsd_elf(fname, elf, &ehdr)) {
+ elf_end(elf);
warnx("%s: not a FreeBSD ELF shared object", fname);
return (0);
}
-
- return (1);
}
- warnx("%s: not a dynamic executable", fname);
- return (0);
+ elf_end(elf);
+ return (1);
}

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