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Fix integer overflow in size suffix parsing

Browse source 
Use __builtin_mul_overflow to detect overflow when applying size
suffixes (K, M, G, T) in str::from for int64_t and uint64_t. Previously,
large values with suffixes could silently wrap around.
This commit is contained in:
Antonio SJ Musumeci 2026-02-25 23:46:53 -06:00 • committed by trapexit
parent a0cff637e1
commit 2754536727
1 changed files with 36 additions and 16 deletions
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52
src/from_string.cpp
View file

@ -69,10 +69,14 @@ str::from(const std::string_view val_,
int
str::from(const std::string_view val_,
int64_t *rv_)
int64_t *rv_)
{
int64_t tmp;
const int base = 10;
constexpr int64_t K = 1024LL;
constexpr int64_t M = K * 1024LL;
constexpr int64_t G = M * 1024LL;
constexpr int64_t T = G * 1024LL;
auto [ptr,ec] = std::from_chars(val_.begin(),
val_.end(),
@ -81,50 +85,60 @@ str::from(const std::string_view val_,
if(ec != std::errc{})
return -EINVAL;
*rv_ = tmp;
if(ptr == val_.end())
return 0;
{
*rv_ = tmp;
return 0;
}
switch(*ptr)
{
case 'b':
case 'B':
*rv_ *= 1ULL;
break;
case 'k':
case 'K':
*rv_ *= 1024ULL;
if(__builtin_mul_overflow(tmp,K,&tmp))
return -EOVERFLOW;
break;
case 'm':
case 'M':
*rv_ *= (1024ULL * 1024ULL);
if(__builtin_mul_overflow(tmp,M,&tmp))
return -EOVERFLOW;
break;
case 'g':
case 'G':
*rv_ *= (1024ULL * 1024ULL * 1024ULL);
if(__builtin_mul_overflow(tmp,G,&tmp))
return -EOVERFLOW;
break;
case 't':
case 'T':
*rv_ *= (1024ULL * 1024ULL * 1024ULL * 1024ULL);
if(__builtin_mul_overflow(tmp,T,&tmp))
return -EOVERFLOW;
break;
default:
return -EINVAL;
}
*rv_ = tmp;
return 0;
}
int
str::from(const std::string_view val_,
uint64_t *rv_)
uint64_t *rv_)
{
uint64_t tmp;
const int base = 10;
constexpr uint64_t K = 1024ULL;
constexpr uint64_t M = K * 1024ULL;
constexpr uint64_t G = M * 1024ULL;
constexpr uint64_t T = G * 1024ULL;
auto [ptr,ec] = std::from_chars(val_.begin(),
val_.end(),
@ -133,41 +147,47 @@ str::from(const std::string_view val_,
if(ec != std::errc{})
return -EINVAL;
*rv_ = tmp;
if(ptr == val_.end())
return 0;
{
*rv_ = tmp;
return 0;
}
switch(*ptr)
{
case 'b':
case 'B':
*rv_ *= 1ULL;
break;
case 'k':
case 'K':
*rv_ *= 1024ULL;
if(__builtin_mul_overflow(tmp,K,&tmp))
return -EOVERFLOW;
break;
case 'm':
case 'M':
*rv_ *= (1024ULL * 1024ULL);
if(__builtin_mul_overflow(tmp,M,&tmp))
return -EOVERFLOW;
break;
case 'g':
case 'G':
*rv_ *= (1024ULL * 1024ULL * 1024ULL);
if(__builtin_mul_overflow(tmp,G,&tmp))
return -EOVERFLOW;
break;
case 't':
case 'T':
*rv_ *= (1024ULL * 1024ULL * 1024ULL * 1024ULL);
if(__builtin_mul_overflow(tmp,T,&tmp))
return -EOVERFLOW;
break;
default:
return -EINVAL;
}
*rv_ = tmp;
return 0;
}