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vdso: Fixes in DT_GNU_HASH handling

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* Hash buckets is an array of 32-bit words. While DT_HASH is 32-bit on
  most platforms except s390 (where it's 64-bit).
* The bloom filter word size differs between 32-bit and 64-bit ELF
  files. This commit adjusts the code to handle both cases.

Signed-off-by: Andrei Vagin <avagin@google.com>
This commit is contained in:
Adrian Reber 2025-02-07 09:24:19 +01:00 committed by Andrei Vagin
parent 4b099510b3
commit e5fe6cc16d
1 changed files with 38 additions and 19 deletions
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53
criu/pie/util-vdso.c
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@ -121,7 +121,8 @@ static int has_elf_identity(Ehdr_t *ehdr)
return true;
}
static int parse_elf_phdr(uintptr_t mem, size_t size, Phdr_t **dynamic, Phdr_t **load)
static int parse_elf_phdr(uintptr_t mem, size_t size,
Phdr_t **dynamic, Phdr_t **load, bool *is_32bit)
{
Ehdr_t *ehdr = (void *)mem;
uintptr_t addr;
@ -136,6 +137,8 @@ static int parse_elf_phdr(uintptr_t mem, size_t size, Phdr_t **dynamic, Phdr_t *
if (!has_elf_identity(ehdr))
return -EINVAL;
*is_32bit = ehdr->e_ident[EI_CLASS] != ELFCLASS64;
addr = mem + ehdr->e_phoff;
if (__ptr_oob(addr, mem, size))
goto err_oob;
@ -272,6 +275,8 @@ typedef unsigned long Hash_t;
typedef Word_t Hash_t;
#endif
typedef uint32_t Hash32_t;
static bool elf_symbol_match(uintptr_t mem, size_t size,
uintptr_t dynsymbol_names, Sym_t *sym,
const char *symbol, const size_t vdso_symbol_length)
@ -297,21 +302,22 @@ static bool elf_symbol_match(uintptr_t mem, size_t size,
static unsigned long elf_symbol_lookup(uintptr_t mem, size_t size,
const char *symbol, uint32_t symbol_hash, unsigned int sym_off,
uintptr_t dynsymbol_names, Dyn_t *dyn_symtab, Phdr_t *load,
Hash_t nbucket, Hash_t nchain, Hash_t *bucket, Hash_t *chain,
uint64_t nbucket, uint64_t nchain, void *_bucket, Hash_t *chain,
const size_t vdso_symbol_length, bool use_gnu_hash)
{
unsigned int j;
uintptr_t addr;
addr = mem + dyn_symtab->d_un.d_ptr - load->p_vaddr;
if (use_gnu_hash) {
Hash32_t *h, hash_val, *bucket = _bucket;
j = bucket[symbol_hash % nbucket];
if (j == STN_UNDEF)
return 0;
addr = mem + dyn_symtab->d_un.d_ptr - load->p_vaddr;
if (use_gnu_hash) {
uint32_t *h = bucket + nbucket + (j - sym_off);
uint32_t hash_val;
h = bucket + nbucket + (j - sym_off);
symbol_hash |= 1;
do {
@ -325,6 +331,12 @@ static unsigned long elf_symbol_lookup(uintptr_t mem, size_t size,
j++;
} while (!(hash_val & 1));
} else {
Hash_t *bucket = _bucket;
j = bucket[symbol_hash % nbucket];
if (j == STN_UNDEF)
return 0;
for (; j < nchain && j != STN_UNDEF; j = chain[j]) {
Sym_t *sym = (void *)addr + sizeof(Sym_t) * j;
@ -338,17 +350,17 @@ static unsigned long elf_symbol_lookup(uintptr_t mem, size_t size,
static int parse_elf_symbols(uintptr_t mem, size_t size, Phdr_t *load,
struct vdso_symtable *t, uintptr_t dynsymbol_names,
Hash_t *hash, Dyn_t *dyn_symtab, bool use_gnu_hash)
Hash_t *hash, Dyn_t *dyn_symtab, bool use_gnu_hash,
bool is_32bit)
{
ARCH_VDSO_SYMBOLS_LIST
const char *vdso_symbols[VDSO_SYMBOL_MAX] = { ARCH_VDSO_SYMBOLS };
const size_t vdso_symbol_length = sizeof(t->symbols[0].name) - 1;
Hash_t *bucket = NULL;
void *bucket = NULL;
Hash_t *chain = NULL;
Hash_t nbucket = 0;
Hash_t nchain = 0;
uint64_t nbucket, nchain = 0;
unsigned int sym_off = 0;
unsigned int i = 0;
@ -358,17 +370,23 @@ static int parse_elf_symbols(uintptr_t mem, size_t size, Phdr_t *load,
if (use_gnu_hash) {
uint32_t *gnu_hash = (uint32_t *)hash;
uint32_t bloom_sz;
size_t *bloom;
nbucket = gnu_hash[0];
sym_off = gnu_hash[1];
bloom_sz = gnu_hash[2];
bloom = (size_t *)&gnu_hash[4];
if (is_32bit) {
uint32_t *bloom;
bloom = (uint32_t *)&gnu_hash[4];
bucket = (Hash_t *)(&bloom[bloom_sz]);
} else {
uint64_t *bloom;
bloom = (uint64_t *)&gnu_hash[4];
bucket = (Hash_t *)(&bloom[bloom_sz]);
}
elf_hash = &elf_gnu_hash;
pr_debug("nbucket %lx sym_off %lx bloom_sz %lx bloom %lx bucket %lx\n",
pr_debug("nbucket %lx sym_off %lx bloom_sz %lx bucket %lx\n",
(unsigned long)nbucket, (unsigned long)sym_off,
(unsigned long)bloom_sz, (unsigned long)bloom,
(unsigned long)bloom_sz,
(unsigned long)bucket);
} else {
nbucket = hash[0];
@ -417,6 +435,7 @@ int vdso_fill_symtable(uintptr_t mem, size_t size, struct vdso_symtable *t)
Dyn_t *dyn_hash = NULL;
Hash_t *hash = NULL;
bool use_gnu_hash;
bool is_32bit;
uintptr_t dynsymbol_names;
uintptr_t addr;
@ -427,7 +446,7 @@ int vdso_fill_symtable(uintptr_t mem, size_t size, struct vdso_symtable *t)
/*
* We need PT_LOAD and PT_DYNAMIC here. Each once.
*/
ret = parse_elf_phdr(mem, size, &dynamic, &load);
ret = parse_elf_phdr(mem, size, &dynamic, &load, &is_32bit);
if (ret < 0)
return ret;
if (!load || !dynamic) {
@ -458,7 +477,7 @@ int vdso_fill_symtable(uintptr_t mem, size_t size, struct vdso_symtable *t)
hash = (void *)addr;
ret = parse_elf_symbols(mem, size, load, t, dynsymbol_names, hash, dyn_symtab,
use_gnu_hash);
use_gnu_hash, is_32bit);
if (ret <0)
return ret;