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scanelf.c
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scanelf.c
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/*
* Copyright 2003-2024 Gentoo Foundation
* Distributed under the terms of the GNU General Public License v2
*
* Copyright 2003-2012 Ned Ludd - <solar@gentoo.org>
* Copyright 2004-2024 Mike Frysinger - <vapier@gentoo.org>
*/
const char argv0[] = "scanelf";
#include "paxinc.h"
#define IS_MODIFIER(c) (c == '%' || c == '#' || c == '+')
/* prototypes */
static int file_matches_list(const char *filename, char **matchlist);
/* variables to control behavior */
static array_t _match_etypes = array_init_decl, *match_etypes = &_match_etypes;
static char scan_ldpath = 0;
static char scan_envpath = 0;
static char scan_symlink = 1;
static char scan_archives = 0;
static char dir_recurse = 0;
static char dir_crossmount = 1;
static char show_pax = 0;
static char show_perms = 0;
static char show_size = 0;
static char show_phdr = 0;
static char show_textrel = 0;
static char show_rpath = 0;
static char show_needed = 0;
static char show_interp = 0;
static char show_bind = 0;
static char show_soname = 0;
static char show_textrels = 0;
static char show_banner = 1;
static char show_endian = 0;
static char show_osabi = 0;
static char show_eabi = 0;
static char be_quiet = 0;
static char be_verbose = 0;
static char be_wewy_wewy_quiet = 0;
static char be_semi_verbose = 0;
static char *find_sym = NULL;
static array_t _find_sym_arr = array_init_decl, *find_sym_arr = &_find_sym_arr;
static array_t _find_sym_regex_arr = array_init_decl, *find_sym_regex_arr = &_find_sym_regex_arr;
static char *find_lib = NULL;
static array_t _find_lib_arr = array_init_decl, *find_lib_arr = &_find_lib_arr;
static char *find_section = NULL;
static array_t _find_section_arr = array_init_decl, *find_section_arr = &_find_section_arr;
static char *out_format = NULL;
static char *search_path = NULL;
static char fix_elf = 0;
static char g_match = 0;
static char use_ldcache = 0;
static char use_ldpath = 0;
static char **qa_textrels = NULL;
static char **qa_execstack = NULL;
static char **qa_wx_load = NULL;
static int match_bits = 0;
static unsigned int match_perms = 0;
static unsigned long setpax = 0UL;
static const char *objdump;
/* Boiler plate wrapper for expanding ELF macros for specific ELF sizes. */
#define _SCANELF_IF_ELF_SIZE(B, x) \
do { \
if (elf->elf_class == ELFCLASS ## B) { \
x(B); \
} \
} while (0)
#define SCANELF_ELF_SIZED(x) \
do { \
_SCANELF_IF_ELF_SIZE(32, x); \
_SCANELF_IF_ELF_SIZE(64, x); \
} while (0)
/* Find the path to a file by name. Note: we do not currently handle the
* empty path element correctly (should behave by searching $PWD). */
static const char *which(const char *fname, const char *envvar)
{
size_t path_len, fname_len;
const char *env_path;
char *path, *p, *ep;
p = getenv(envvar);
if (p)
return p;
env_path = getenv("PATH");
if (!env_path)
return NULL;
/* Create a copy of the $PATH that we can safely modify.
* Make it a little bigger so we can append "/fname".
* We do this twice -- once for a perm copy, and once for
* room at the end of the last element. */
path_len = strlen(env_path);
fname_len = strlen(fname);
path = xmalloc(path_len + (fname_len * 2) + 2 + 2);
memcpy(path, env_path, path_len + 1);
p = path + path_len + 1 + fname_len + 1;
*p = '/';
memcpy(p + 1, fname, fname_len + 1);
/* Repoint fname to the copy in the env string as it has
* the leading slash which we can include in a single memcpy.
* Increase the fname len to include the '/' and '\0'. */
fname = p;
fname_len += 2;
p = path;
while (p) {
ep = strchr(p, ':');
/* Append the /foo path to the current element. */
if (ep)
memcpy(ep, fname, fname_len);
else
memcpy(path + path_len, fname, fname_len);
if (access(p, R_OK) != -1)
return p;
p = ep;
if (ep) {
/* If not the last element, restore the chunk we clobbered. */
size_t offset = ep - path;
size_t restore = min(path_len - offset, fname_len);
memcpy(ep, env_path + offset, restore);
++p;
}
}
free(path);
return NULL;
}
/*
* Return the index into the program header table for the |p_type| segment.
* Useful only when there is one instance of a particular type.
*/
static ssize_t scanelf_file_find_phdr(elfobj *elf, uint32_t p_type)
{
ssize_t ret = -1;
#define FIND_PT_TYPE(B) \
size_t i; \
const Elf##B##_Ehdr *ehdr = EHDR ## B (elf->ehdr); \
const Elf##B##_Phdr *phdr = PHDR ## B (elf->phdr); \
\
for (i = 0; i < EGET(ehdr->e_phnum); i++) { \
if (EGET(phdr[i].p_type) != p_type) \
continue; \
\
if (ret == -1) \
ret = i; \
else \
warnf("ELF has more than one %s segment !?", get_elfptype(p_type)); \
}
if (elf->phdr)
SCANELF_ELF_SIZED(FIND_PT_TYPE);
return ret;
}
static const void *scanelf_file_get_pt_dynamic(elfobj *elf)
{
ssize_t i = scanelf_file_find_phdr(elf, PT_DYNAMIC);
if (i == -1)
return NULL;
#define CHECK_PT_DYNAMIC(B) \
const Elf##B##_Phdr *phdr = &PHDR##B(elf->phdr)[i]; \
Elf##B##_Off offset; \
\
if (EGET(phdr->p_filesz) == 0) \
break; \
offset = EGET(phdr->p_offset); \
if (!VALID_RANGE(elf, offset, sizeof(Elf##B##_Dyn))) \
break; \
return phdr;
SCANELF_ELF_SIZED(CHECK_PT_DYNAMIC);
return NULL;
}
#define scanelf_dt_for_each(B, elf, dyn) \
{ \
const Elf##B##_Phdr *_phdr = scanelf_file_get_pt_dynamic(elf); \
dyn = (_phdr == NULL) ? elf->data_end : DYN##B(elf->vdata + EGET(_phdr->p_offset)); \
} \
--dyn; \
while ((void *)++dyn < elf->data_end - sizeof(*dyn) && EGET(dyn->d_tag) != DT_NULL)
/* sub-funcs for scanelf_fileat() */
static void scanelf_file_get_symtabs(elfobj *elf, const void **sym, const void **str)
{
/* find the best SHT_DYNSYM and SHT_STRTAB sections */
/* debug sections */
const void *symtab = elf_findsecbyname(elf, ".symtab");
const void *strtab = elf_findsecbyname(elf, ".strtab");
/* runtime sections */
const void *dynsym = elf_findsecbyname(elf, ".dynsym");
const void *dynstr = elf_findsecbyname(elf, ".dynstr");
/*
* If the sections are marked NOBITS, then they don't exist, so we just
* skip them. This let's us work sanely with splitdebug ELFs (rather
* than spewing a lot of "corrupt ELF" messages later on). In malformed
* ELFs, the section might be wrongly set to NOBITS, but screw em.
*
* We need to make sure the debug/runtime sym/str sets are used together
* as they are generated in sync. Trying to mix them won't work.
*/
#define GET_SYMTABS(B) \
const Elf ## B ## _Shdr *esymtab = symtab; \
const Elf ## B ## _Shdr *estrtab = strtab; \
const Elf ## B ## _Shdr *edynsym = dynsym; \
const Elf ## B ## _Shdr *edynstr = dynstr; \
\
if (!VALID_SHDR(elf, esymtab)) \
symtab = NULL; \
if (!VALID_SHDR(elf, edynsym)) \
dynsym = NULL; \
if (!VALID_SHDR(elf, estrtab)) \
strtab = NULL; \
if (!VALID_SHDR(elf, edynstr)) \
dynstr = NULL; \
\
/* Use the set with more symbols if both exist. */ \
if (symtab && dynsym && strtab && dynstr) { \
if (EGET(esymtab->sh_size) > EGET(edynsym->sh_size)) \
goto debug##B; \
else \
goto runtime##B; \
} else if (symtab && strtab) { \
debug##B: \
*sym = symtab; \
*str = strtab; \
return; \
} else if (dynsym && dynstr) { \
runtime##B: \
*sym = dynsym; \
*str = dynstr; \
return; \
} else { \
*sym = *str = NULL; \
}
SCANELF_ELF_SIZED(GET_SYMTABS);
if (*sym && *str)
return;
/*
* damn, they're really going to make us work for it huh?
* reconstruct the section header info out of the dynamic
* tags so we can see what symbols this guy uses at runtime.
*/
#define GET_SYMTABS_DT(B) \
size_t i; \
static Elf ## B ## _Shdr sym_shdr, str_shdr; \
const Elf ## B ## _Ehdr *ehdr = EHDR ## B (elf->ehdr); \
const Elf ## B ## _Phdr *phdr = PHDR ## B (elf->phdr); \
Elf ## B ## _Addr vsym, vstr, vhash, vgnu_hash; \
const Elf ## B ## _Dyn *dyn; \
\
/* lookup symbols used at runtime with DT_SYMTAB / DT_STRTAB */ \
vsym = vstr = vhash = vgnu_hash = 0; \
memset(&sym_shdr, 0, sizeof(sym_shdr)); \
memset(&str_shdr, 0, sizeof(str_shdr)); \
\
/* Find the dynamic headers */ \
scanelf_dt_for_each(B, elf, dyn) { \
switch (EGET(dyn->d_tag)) { \
case DT_SYMTAB: vsym = EGET(dyn->d_un.d_val); break; \
case DT_SYMENT: sym_shdr.sh_entsize = dyn->d_un.d_val; break; \
case DT_STRTAB: vstr = EGET(dyn->d_un.d_val); break; \
case DT_STRSZ: str_shdr.sh_size = dyn->d_un.d_val; break; \
case DT_HASH: vhash = EGET(dyn->d_un.d_val); break; \
/*case DT_GNU_HASH: vgnu_hash = EGET(dyn->d_un.d_val); break;*/ \
} \
} \
if (!vsym || !vstr || !(vhash || vgnu_hash)) \
return; \
\
/* calc offset into the ELF by finding the load addr of the syms */ \
for (i = 0; i < EGET(ehdr->e_phnum); i++) { \
Elf ## B ## _Addr vaddr = EGET(phdr[i].p_vaddr); \
Elf ## B ## _Addr filesz = EGET(phdr[i].p_filesz); \
Elf ## B ## _Off offset = EGET(phdr[i].p_offset); \
Elf ## B ## _Off hash_offset = offset + (vhash - vaddr); \
\
if (EGET(phdr[i].p_type) != PT_LOAD) \
continue; \
\
if (!VALID_RANGE(elf, offset, filesz)) \
goto corrupt_hash; \
if (!VALID_RANGE(elf, hash_offset, sizeof(Elf32_Word) * 4)) \
goto corrupt_hash; \
\
if (vhash >= vaddr && vhash < vaddr + filesz) { \
/* Scan the hash table to see how many entries we have */ \
Elf32_Word max_sym_idx = 0; \
const Elf32_Word *hashtbl = elf->vdata + hash_offset; \
Elf32_Word b, nbuckets = EGET(hashtbl[0]); \
Elf32_Word nchains = EGET(hashtbl[1]); \
const Elf32_Word *buckets = &hashtbl[2]; \
const Elf32_Word *chains = &buckets[nbuckets]; \
Elf32_Word sym_idx; \
Elf32_Word chained; \
\
if (!VALID_RANGE(elf, hash_offset, nbuckets * (uint64_t)4)) \
goto corrupt_hash; \
if (!VALID_RANGE(elf, hash_offset, nchains * (uint64_t)4)) \
goto corrupt_hash; \
\
for (b = 0; b < nbuckets; ++b) { \
if (!buckets[b]) \
continue; \
for (sym_idx = buckets[b], chained = 0; \
(sym_idx < nchains && sym_idx && chained <= nchains && \
(void *)&chains[sym_idx] + sizeof(*chains) < elf->data_end); \
sym_idx = chains[sym_idx], ++chained) { \
if (max_sym_idx < sym_idx) \
max_sym_idx = sym_idx; \
} \
if (chained > nchains) \
goto corrupt_hash; \
} \
ESET(sym_shdr.sh_size, sym_shdr.sh_entsize * max_sym_idx); \
} \
\
if (vsym >= vaddr && vsym < vaddr + filesz) { \
const Elf##B##_Shdr *shdr = &sym_shdr; \
ESET(sym_shdr.sh_offset, offset + (vsym - vaddr)); \
if (VALID_SHDR(elf, shdr)) \
*sym = shdr; \
} \
\
if (vstr >= vaddr && vstr < vaddr + filesz) { \
const Elf##B##_Shdr *shdr = &str_shdr; \
ESET(str_shdr.sh_offset, offset + (vstr - vaddr)); \
if (VALID_SHDR(elf, shdr)) \
*str = shdr; \
} \
}
if (elf->phdr)
SCANELF_ELF_SIZED(GET_SYMTABS_DT);
return;
corrupt_hash:
warn("%s: ELF hash table is corrupt", elf->filename);
}
static const char *scanelf_file_pax(elfobj *elf, char *found_pax)
{
static char ret[7];
unsigned long i, shown;
if (!show_pax) return NULL;
shown = 0;
memset(&ret, 0, sizeof(ret));
#define SHOW_PAX(B) \
const Elf ## B ## _Ehdr *ehdr = EHDR ## B (elf->ehdr); \
const Elf ## B ## _Phdr *phdr = PHDR ## B (elf->phdr); \
for (i = 0; i < EGET(ehdr->e_phnum); i++) { \
if (EGET(phdr[i].p_type) != PT_PAX_FLAGS) \
continue; \
if (fix_elf && setpax) { \
/* set the paxctl flags */ \
Elf ## B ## _Phdr *wphdr = (void *)&phdr[i]; \
ESET(wphdr->p_flags, setpax); \
} \
if (be_quiet && (EGET(phdr[i].p_flags) == (PF_NOEMUTRAMP | PF_NORANDEXEC))) \
continue; \
memcpy(ret, pax_short_pf_flags(EGET(phdr[i].p_flags)), 6); \
*found_pax = 1; \
++shown; \
break; \
}
if (elf->phdr)
SCANELF_ELF_SIZED(SHOW_PAX);
/* Note: We do not support setting EI_PAX if not PT_PAX_FLAGS
* was found. This is known to break ELFs on glibc systems,
* and mainline PaX has deprecated use of this for a long time.
* We could support changing PT_GNU_STACK, but that doesn't
* seem like it's worth the effort. #411919
*/
/* fall back to EI_PAX if no PT_PAX was found */
if (!*ret) {
const char *paxflags = pax_short_hf_flags(EI_PAX_FLAGS(elf));
if (!be_quiet || (be_quiet && EI_PAX_FLAGS(elf))) {
*found_pax = 1;
return (be_wewy_wewy_quiet ? NULL : paxflags);
}
strcpy(ret, paxflags);
}
if (be_wewy_wewy_quiet || (be_quiet && !shown))
return NULL;
else
return ret;
}
static const char *scanelf_file_phdr(elfobj *elf, char *found_phdr, char *found_relro, char *found_load)
{
static char ret[12];
char *found;
unsigned long i, shown, multi_stack, multi_relro, multi_load;
if (!show_phdr) return NULL;
memcpy(ret, "--- --- ---\0", 12);
shown = 0;
multi_stack = multi_relro = multi_load = 0;
#define NOTE_GNU_STACK ".note.GNU-stack"
#define SHOW_PHDR(B) \
const Elf ## B ## _Ehdr *ehdr = EHDR ## B (elf->ehdr); \
Elf ## B ## _Off offset; \
uint32_t flags, check_flags; \
if (elf->phdr != NULL) { \
const Elf ## B ## _Phdr *phdr = PHDR ## B (elf->phdr); \
for (i = 0; i < EGET(ehdr->e_phnum); ++i) { \
if (EGET(phdr[i].p_type) == PT_GNU_STACK) { \
if (multi_stack++) \
warnf("%s: multiple PT_GNU_STACK's !?", elf->filename); \
if (file_matches_list(elf->filename, qa_execstack)) \
continue; \
found = found_phdr; \
offset = 0; \
check_flags = PF_X; \
} else if (EGET(phdr[i].p_type) == PT_GNU_RELRO) { \
if (multi_relro++) \
warnf("%s: multiple PT_GNU_RELRO's !?", elf->filename); \
found = found_relro; \
offset = 4; \
check_flags = PF_X; \
} else if (EGET(phdr[i].p_type) == PT_LOAD) { \
if (file_matches_list(elf->filename, qa_wx_load)) \
continue; \
found = found_load; \
offset = 8; \
check_flags = PF_W|PF_X; \
} else \
continue; \
flags = EGET(phdr[i].p_flags); \
if (be_quiet && ((flags & check_flags) != check_flags)) \
continue; \
if ((EGET(phdr[i].p_type) != PT_LOAD) && (fix_elf && ((flags & PF_X) != flags))) { \
Elf ## B ## _Phdr *wphdr = (void *)&phdr[i]; \
ESET(wphdr->p_flags, flags & (PF_X ^ (size_t)-1)); \
ret[3] = ret[7] = '!'; \
flags = EGET(phdr[i].p_flags); \
} \
memcpy(ret+offset, gnu_short_stack_flags(flags), 3); \
*found = 1; \
++shown; \
} \
} else if (elf->shdr != NULL) { \
/* no program headers which means this is prob an object file */ \
const Elf ## B ## _Shdr *shdr = SHDR ## B (elf->shdr); \
uint16_t shstrndx = EGET(ehdr->e_shstrndx); \
const Elf ## B ## _Shdr *strtbl = shdr + shstrndx; \
uint16_t shnum = EGET(ehdr->e_shnum); \
if (shstrndx >= shnum || !VALID_SHDR(elf, strtbl)) \
goto corrupt_shdr; \
/* let's flag -w/+x object files since the final ELF will most likely \
* need write access to the stack (who doesn't !?). so the combined \
* output will bring in +w automatically and that's bad. \
*/ \
check_flags = /*SHF_WRITE|*/SHF_EXECINSTR; \
for (i = 0; i < shnum; ++i) { \
if (EGET(shdr[i].sh_type) != SHT_PROGBITS) continue; \
offset = EGET(strtbl->sh_offset) + EGET(shdr[i].sh_name); \
if (!VALID_RANGE(elf, offset, sizeof(NOTE_GNU_STACK))) \
continue; \
if (!strcmp(elf->data + offset, NOTE_GNU_STACK)) { \
if (multi_stack++) warnf("%s: multiple .note.GNU-stack's !?", elf->filename); \
if (file_matches_list(elf->filename, qa_execstack)) \
continue; \
flags = EGET(shdr[i].sh_flags); \
if (be_quiet && ((flags & check_flags) != check_flags)) \
continue; \
++*found_phdr; \
shown = 1; \
if (flags & SHF_WRITE) ret[0] = 'W'; \
if (flags & SHF_ALLOC) ret[1] = 'A'; \
if (flags & SHF_EXECINSTR) ret[2] = 'X'; \
if (flags & 0xFFFFFFF8) warn("Invalid section flags for GNU-stack"); \
break; \
} \
} \
if (!multi_stack) { \
if (file_matches_list(elf->filename, qa_execstack)) \
return NULL; \
*found_phdr = 1; \
shown = 1; \
memcpy(ret, "!WX", 3); \
} \
}
SCANELF_ELF_SIZED(SHOW_PHDR);
if (be_wewy_wewy_quiet || (be_quiet && !shown))
return NULL;
else
return ret;
corrupt_shdr:
warnf("%s: section table is corrupt", elf->filename);
return NULL;
}
/*
* See if this ELF contains a DT_TEXTREL tag in any of its
* PT_DYNAMIC sections.
*/
static const char *scanelf_file_textrel(elfobj *elf, char *found_textrel)
{
static const char *ret = "TEXTREL";
if (!show_textrel && !show_textrels) return NULL;
if (file_matches_list(elf->filename, qa_textrels)) return NULL;
#define SHOW_TEXTREL(B) \
const Elf ## B ## _Dyn *dyn; \
\
scanelf_dt_for_each(B, elf, dyn) { \
if (EGET(dyn->d_tag) == DT_TEXTREL) { /*dyn->d_tag != DT_FLAGS)*/ \
*found_textrel = 1; \
/*if (dyn->d_un.d_val & DF_TEXTREL)*/ \
return (be_wewy_wewy_quiet ? NULL : ret); \
} \
}
if (elf->phdr)
SCANELF_ELF_SIZED(SHOW_TEXTREL);
if (be_quiet || be_wewy_wewy_quiet)
return NULL;
else
return " - ";
}
/*
* Scan the .text section to see if there are any relocations in it.
* Should rewrite this to check PT_LOAD sections that are marked
* Executable rather than the section named '.text'.
*/
static const char *scanelf_file_textrels(elfobj *elf, char *found_textrels, char *found_textrel)
{
unsigned long r, rmax;
const void *symtab_void, *strtab_void;
if (!show_textrels) return NULL;
/* don't search for TEXTREL's if the ELF doesn't have any */
if (!*found_textrel) scanelf_file_textrel(elf, found_textrel);
if (!*found_textrel) return NULL;
scanelf_file_get_symtabs(elf, &symtab_void, &strtab_void);
#define SHOW_TEXTRELS(B) \
size_t i; \
const Elf ## B ## _Ehdr *ehdr = EHDR ## B (elf->ehdr); \
const Elf ## B ## _Phdr *phdr; \
const Elf ## B ## _Shdr *symtab = SHDR ## B (symtab_void); \
const Elf ## B ## _Shdr *strtab = SHDR ## B (strtab_void); \
const Elf ## B ## _Rel *rel; \
const Elf ## B ## _Rela *rela; \
const Elf ## B ## _Dyn *dyn, *drel, *drelsz, *drelent, *dpltrel; \
uint32_t pltrel; \
Elf ## B ## _Addr load_address = 0; \
Elf ## B ## _Addr file_offset; \
\
/* Walk all the dynamic tags to find relocation info */ \
drel = drelsz = drelent = dpltrel = NULL; \
scanelf_dt_for_each(B, elf, dyn) { \
switch (EGET(dyn->d_tag)) { \
case DT_REL: \
case DT_RELA: \
drel = dyn; \
break; \
case DT_RELSZ: \
case DT_RELASZ: \
drelsz = dyn; \
break; \
case DT_RELENT: \
case DT_RELAENT: \
drelent = dyn; \
break; \
case DT_PLTREL: \
dpltrel = dyn; \
break; \
} \
} \
if (!drel || !drelsz || !drelent || !dpltrel) { \
warnf("ELF is missing relocation information"); \
break; \
} \
phdr = PHDR ## B(elf->phdr); \
/* Lookup load base: byte 0 is mapped at load_address */ \
for (i = 0; i < EGET(ehdr->e_phnum); ++i) { \
/* Only care about loadable segments. */ \
if (EGET(phdr[i].p_type) != PT_LOAD) \
continue; \
/* We search for the first program header to map into memory */ \
if (EGET(phdr[i].p_offset) != 0) \
continue; \
load_address = EGET(phdr[i].p_vaddr); \
} \
switch (EGET(dpltrel->d_un.d_val)) { \
case DT_REL: \
file_offset = EGET(drel->d_un.d_val) - load_address; \
if (!VALID_RANGE(elf, file_offset, sizeof (drel->d_un.d_val))) { \
rel = NULL; \
rela = NULL; \
warn("%s: DT_REL is out of file range", elf->filename); \
break; \
} \
rel = REL##B(elf->vdata + file_offset); \
rela = NULL; \
pltrel = DT_REL; \
break; \
case DT_RELA: \
file_offset = EGET(drel->d_un.d_val) - load_address; \
if (!VALID_RANGE(elf, file_offset, sizeof (drel->d_un.d_val))) { \
rel = NULL; \
rela = NULL; \
warn("%s: DT_RELA is out of file range", elf->filename); \
break; \
} \
rel = NULL; \
rela = RELA##B(elf->vdata + file_offset); \
pltrel = DT_RELA; \
break; \
default: \
warn("Unknown relocation type"); \
rel = NULL; \
rela = NULL; \
break; \
} \
if (!rel && !rela) \
break; \
rmax = EGET(drelsz->d_un.d_val) / EGET(drelent->d_un.d_val); \
\
/* search the program segments for relocations */ \
for (i = 0; i < EGET(ehdr->e_phnum); ++i) { \
Elf ## B ## _Addr vaddr = EGET(phdr[i].p_vaddr); \
uint ## B ## _t memsz = EGET(phdr[i].p_memsz); \
\
/* Only care about loadable segments. */ \
if (EGET(phdr[i].p_type) != PT_LOAD) \
continue; \
/* Only care about executable segments. */ \
if ((EGET(phdr[i].p_flags) & PF_X) != PF_X) \
continue; \
\
/* now see if any of the relocs touch this segment */ \
for (r = 0; r < rmax; ++r) { \
unsigned long sym_max; \
Elf ## B ## _Addr offset_tmp; \
const Elf ## B ## _Sym *func; \
const Elf ## B ## _Sym *sym; \
Elf ## B ## _Addr r_offset; \
uint ## B ## _t r_info; \
if (pltrel == DT_REL) { \
r_offset = EGET(rel[r].r_offset); \
r_info = EGET(rel[r].r_info); \
} else { \
r_offset = EGET(rela[r].r_offset); \
r_info = EGET(rela[r].r_info); \
} \
/* make sure this relocation is inside of the .text */ \
if (r_offset < vaddr || r_offset >= vaddr + memsz) { \
if (be_verbose <= 2) continue; \
} else \
*found_textrels = 1; \
/* locate this relocation symbol name */ \
sym = SYM ## B (elf->vdata + EGET(symtab->sh_offset)); \
if ((void*)sym > elf->data_end) { \
warn("%s: corrupt ELF symbol", elf->filename); \
continue; \
} \
sym_max = ELF ## B ## _R_SYM(r_info); \
if (sym_max * EGET(symtab->sh_entsize) < symtab->sh_size) \
sym += sym_max; \
else \
sym = NULL; \
sym_max = EGET(symtab->sh_size) / EGET(symtab->sh_entsize); \
/* show the raw details about this reloc */ \
printf(" %s: ", elf->base_filename); \
if (!strtab) \
printf("(missing symbols)"); \
else if (sym && sym->st_name) \
printf("%s", elf->data + EGET(strtab->sh_offset) + EGET(sym->st_name)); \
else \
printf("(memory/data?)"); \
printf(" [r_offset=0x%lX]", (unsigned long)r_offset); \
printf(" r_type=%lu", (unsigned long)ELF ## B ## _ST_TYPE(r_info)); \
/* now try to find the closest symbol that this rel is probably in */ \
sym = SYM ## B (elf->vdata + EGET(symtab->sh_offset)); \
func = NULL; \
offset_tmp = 0; \
while (sym_max--) { \
if (EGET(sym->st_value) < r_offset && EGET(sym->st_value) > offset_tmp) { \
func = sym; \
offset_tmp = EGET(sym->st_value); \
} \
++sym; \
} \
printf(" in "); \
if (func && func->st_name) { \
if (strtab) { \
const char *func_name = elf->data + EGET(strtab->sh_offset) + EGET(func->st_name); \
if (r_offset > EGET(func->st_size)) \
printf("(optimized out: previous %s)", func_name); \
else \
printf("%s", func_name); \
} else \
printf("(missing symbols)"); \
} else \
printf("(optimized out?)"); \
printf(" [closest_prev_sym=0x%lX]\n", (unsigned long)offset_tmp); \
if (be_verbose && objdump && func) { \
Elf ## B ## _Addr end_addr = offset_tmp + EGET(func->st_size); \
char *sysbuf; \
int ret; \
if (end_addr < r_offset) \
/* not uncommon when things are optimized out */ \
end_addr = r_offset + 0x100; \
ret = asprintf( \
&sysbuf, \
"%s -r -R -d -w -l --start-address=0x%lX --stop-address=0x%lX %s | " \
"grep --color -i -C 3 '.*[[:space:]]%lX:[[:space:]]*R_.*'\n", \
objdump, \
(unsigned long)offset_tmp, \
(unsigned long)end_addr, \
elf->filename, \
(unsigned long)r_offset); \
if (ret < 0) \
errp("asprintf() failed"); \
fflush(stdout); \
if (system(sysbuf)) {/* don't care */} \
fflush(stdout); \
free(sysbuf); \
} \
} \
}
if (symtab_void && elf->phdr)
SCANELF_ELF_SIZED(SHOW_TEXTRELS);
if (!*found_textrels)
warnf("ELF %s has TEXTREL markings but doesn't appear to have any real TEXTREL's !?", elf->filename);
return NULL;
}
static void rpath_security_checks(elfobj *elf, const char *item, const char *dt_type)
{
struct stat st;
switch (*item) {
case '/': break;
case '.':
warnf("Security problem with relative %s '%s' in %s", dt_type, item, elf->filename);
break;
case ':':
case '\0':
warnf("Security problem NULL %s in %s", dt_type, elf->filename);
break;
case '$':
if (fstat(elf->fd, &st) != -1)
if ((st.st_mode & S_ISUID) || (st.st_mode & S_ISGID))
warnf("Security problem with %s='%s' in %s with mode set of %o",
dt_type, item, elf->filename, (unsigned int) st.st_mode & 07777);
break;
default:
warnf("Maybe? sec problem with %s='%s' in %s", dt_type, item, elf->filename);
break;
}
if (fix_elf)
warnf("Note: RPATH has been automatically fixed, but this should be fixed in the package itself");
}
static void scanelf_file_rpath(elfobj *elf, char *found_rpath, char **ret, size_t *ret_len)
{
const char *rpath, *runpath, **r;
const void *strtab_void;
if (!show_rpath) return;
/*
* TODO: Switch to the string table found via dynamic tags.
* Note: We can't use scanelf_file_get_symtabs as these strings are
* *only* found in dynstr and not in .strtab.
*/
strtab_void = elf_findsecbyname(elf, ".dynstr");
rpath = runpath = NULL;
#define SHOW_RPATH(B) \
const Elf ## B ## _Dyn *dyn; \
const Elf ## B ## _Shdr *strtab = SHDR ## B (strtab_void); \
Elf ## B ## _Off offset; \
Elf ## B ## _Xword word; \
\
/* Just scan dynamic RPATH/RUNPATH headers */ \
scanelf_dt_for_each(B, elf, dyn) { \
word = EGET(dyn->d_tag); \
if (word == DT_RPATH) { \
r = &rpath; \
} else if (word == DT_RUNPATH) { \
r = &runpath; \
} else { \
continue; \
} \
/* Verify the memory is somewhat sane */ \
offset = EGET(strtab->sh_offset) + EGET(dyn->d_un.d_ptr); \
if (offset < (Elf ## B ## _Off)elf->len) { \
if (*r) warn("ELF has multiple %s's !?", get_elfdtype(word)); \
*r = elf->data + offset; \
/* cache the length in case we need to nuke this section later on */ \
if (fix_elf) \
offset = strlen(*r); \
/* If quiet, don't output paths in ld.so.conf */ \
if (be_quiet) { \
size_t len; \
const char *start, *end; \
/* note that we only 'chop' off leading known paths. */ \
/* since *r is read-only memory, we can only move the ptr forward. */ \
start = *r; \
/* scan each path in : delimited list */ \
while (start) { \
rpath_security_checks(elf, start, get_elfdtype(word)); \
end = strchr(start, ':'); \
len = (end ? (size_t)(end - start) : strlen(start)); \
if (use_ldcache) { \
size_t n; \
const char *ldpath; \
array_for_each(ldpaths, n, ldpath) \
if (!strncmp(ldpath, start, len) && !ldpath[len]) { \
*r = end; \
/* corner case ... if RPATH reads "/usr/lib:", we want \
* to show ':' rather than '' */ \
if (end && end[1] != '\0') \
(*r)++; \
break; \
} \
} \
if (!*r || !end) \
break; \
else \
start = start + len + 1; \
} \
} \
if (*r) { \
if (fix_elf > 2 || (fix_elf && **r == '\0')) { \
/* just nuke it */ \
nuke_it##B: { \
/* We have to cast away the const. \
* We know we mapped the backing memory as writable. */ \
Elf ## B ## _Dyn *wdyn = (void *)dyn; \
memset((void *)*r, 0x00, offset); \
*r = NULL; \
ESET(wdyn->d_tag, DT_DEBUG); \
ESET(wdyn->d_un.d_ptr, 0); \
} \
} else if (fix_elf) { \
/* try to clean "bad" paths */ \
size_t len, tmpdir_len; \
char *start, *end; \
const char *tmpdir; \
start = (void *)*r; \
tmpdir = (getenv("TMPDIR") ? : "."); \
tmpdir_len = strlen(tmpdir); \
while (1) { \
end = strchr(start, ':'); \
if (start == end) { \
eat_this_path##B: \
len = strlen(end); \
memmove(start, end+1, len); \
start[len-1] = '\0'; \
end = start - 1; \
} else if (tmpdir && !strncmp(start, tmpdir, tmpdir_len)) { \
if (!end) { \
if (start == *r) \
goto nuke_it##B; \
*--start = '\0'; \
} else \
goto eat_this_path##B; \
} \
if (!end) \
break; \
start = end + 1; \
} \
if (**r == '\0') \
goto nuke_it##B; \
} \
if (*r) \
*found_rpath = 1; \
} \
} \
}
if (elf->phdr && strtab_void)
SCANELF_ELF_SIZED(SHOW_RPATH);
if (be_wewy_wewy_quiet) return;
if (rpath && runpath) {
if (!strcmp(rpath, runpath)) {
xstrcat(ret, runpath, ret_len);
} else {
fprintf(stderr, "RPATH [%s] != RUNPATH [%s]\n", rpath, runpath);
xchrcat(ret, '{', ret_len);
xstrcat(ret, rpath, ret_len);
xchrcat(ret, ',', ret_len);
xstrcat(ret, runpath, ret_len);
xchrcat(ret, '}', ret_len);
}
} else if (rpath || runpath)
xstrcat(ret, (runpath ? runpath : rpath), ret_len);
else if (!be_quiet)
xstrcat(ret, " - ", ret_len);
}
static char *lookup_config_lib(const char *fname)
{
static char buf[__PAX_UTILS_PATH_MAX] = "";
const char *ldpath;
size_t n;
array_for_each(ldpaths, n, ldpath) {
snprintf(buf, sizeof(buf), "%s/%s", root_rel_path(ldpath), fname);
if (faccessat(root_fd, buf, F_OK, AT_SYMLINK_NOFOLLOW) == 0)
return buf;
}
return NULL;
}
static const char *scanelf_file_needed_lib(elfobj *elf, char *found_needed, char *found_lib, int op, char **ret, size_t *ret_len)
{
const char *needed;
const void *strtab_void;
char *p;
/*
* -n -> op==0 -> print all
* -N -> op==1 -> print requested
*/
if ((op == 0 && !show_needed) || (op == 1 && !find_lib))
return NULL;
/*
* TODO: Switch to the string table found via dynamic tags.
* Note: We can't use scanelf_file_get_symtabs as these strings are
* *only* found in dynstr and not in .strtab.
*/
strtab_void = elf_findsecbyname(elf, ".dynstr");
#define SHOW_NEEDED(B) \
const Elf ## B ## _Dyn *dyn; \
const Elf ## B ## _Shdr *strtab = SHDR ## B (strtab_void); \
size_t matched = 0; \
\
/* Walk all the dynamic tags to find NEEDED entries */ \
scanelf_dt_for_each(B, elf, dyn) { \
if (EGET(dyn->d_tag) == DT_NEEDED) { \
Elf ## B ## _Off offset = EGET(strtab->sh_offset) + EGET(dyn->d_un.d_ptr); \
if (offset >= (Elf ## B ## _Off)elf->len) \
continue; \
needed = elf->data + offset; \
if (op == 0) { \
/* -n -> print all entries */ \
if (!be_wewy_wewy_quiet) { \
if (*found_needed) xchrcat(ret, ',', ret_len); \
if (use_ldpath) { \
if ((p = lookup_config_lib(needed)) != NULL) \
needed = p; \
} else if (use_ldcache) { \
if ((p = ldso_cache_lookup_lib(elf, needed)) != NULL) \
needed = p; \
} \
xstrcat(ret, needed, ret_len); \
} \
*found_needed = 1; \
} else { \
/* -N -> print matching entries */ \
size_t n; \
const char *find_lib_name; \
\
array_for_each(find_lib_arr, n, find_lib_name) { \