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avoid using undefined pointer arithmetic in dladdr

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This commit is contained in:
Rich Felker 2018-06-27 15:29:12 -04:00
parent a0d64dccbc
commit e829695fcc
1 changed files with 9 additions and 8 deletions
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17
ldso/dynlink.c
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@ -1943,16 +1943,17 @@ failed:
return 0; return 0;
} }
int dladdr(const void *addr, Dl_info *info) int dladdr(const void *addr_arg, Dl_info *info)
{ {
size_t addr = (size_t)addr_arg;
struct dso *p; struct dso *p;
Sym *sym, *bestsym; Sym *sym, *bestsym;
uint32_t nsym; uint32_t nsym;
char *strings; char *strings;
void *best = 0; size_t best = 0;
pthread_rwlock_rdlock(&lock); pthread_rwlock_rdlock(&lock);
p = addr2dso((size_t)addr); p = addr2dso(addr);
pthread_rwlock_unlock(&lock); pthread_rwlock_unlock(&lock);
if (!p) return 0; if (!p) return 0;
@ -1962,10 +1963,10 @@ int dladdr(const void *addr, Dl_info *info)
nsym = count_syms(p); nsym = count_syms(p);
if (DL_FDPIC) { if (DL_FDPIC) {
size_t idx = ((size_t)addr-(size_t)p->funcdescs) size_t idx = (addr-(size_t)p->funcdescs)
/ sizeof(*p->funcdescs); / sizeof(*p->funcdescs);
if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) { if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
best = p->funcdescs + idx; best = (size_t)(p->funcdescs + idx);
bestsym = sym + idx; bestsym = sym + idx;
} }
} }
@ -1974,7 +1975,7 @@ int dladdr(const void *addr, Dl_info *info)
if (sym->st_value if (sym->st_value
&& (1<<(sym->st_info&0xf) & OK_TYPES) && (1<<(sym->st_info&0xf) & OK_TYPES)
&& (1<<(sym->st_info>>4) & OK_BINDS)) { && (1<<(sym->st_info>>4) & OK_BINDS)) {
void *symaddr = laddr(p, sym->st_value); size_t symaddr = (size_t)laddr(p, sym->st_value);
if (symaddr > addr || symaddr < best) if (symaddr > addr || symaddr < best)
continue; continue;
best = symaddr; best = symaddr;
@ -1987,12 +1988,12 @@ int dladdr(const void *addr, Dl_info *info)
if (!best) return 0; if (!best) return 0;
if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC) if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
best = p->funcdescs + (bestsym - p->syms); best = (size_t)(p->funcdescs + (bestsym - p->syms));
info->dli_fname = p->name; info->dli_fname = p->name;
info->dli_fbase = p->map; info->dli_fbase = p->map;
info->dli_sname = strings + bestsym->st_name; info->dli_sname = strings + bestsym->st_name;
info->dli_saddr = best; info->dli_saddr = (void *)best;
return 1; return 1;
} }