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setenv.c: Get rid of alloca.

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Use malloc rather than alloca to avoid potential stack overflow.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Joe Simmons-Talbott 2023-06-30 14:31:45 +00:00
parent 9555be54ef
commit 9401024e5e
1 changed files with 6 additions and 34 deletions
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40
stdlib/setenv.c
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@ -182,18 +182,11 @@ __add_to_environ (const char *name, const char *value, const char *combined,
{ {
const size_t varlen = namelen + 1 + vallen; const size_t varlen = namelen + 1 + vallen;
#ifdef USE_TSEARCH #ifdef USE_TSEARCH
char *new_value; char *new_value = malloc (varlen);
int use_alloca = __libc_use_alloca (varlen); if (new_value == NULL)
if (__builtin_expect (use_alloca, 1))
new_value = (char *) alloca (varlen);
else
{ {
new_value = malloc (varlen); UNLOCK;
if (new_value == NULL) return -1;
{
UNLOCK;
return -1;
}
} }
# ifdef _LIBC # ifdef _LIBC
__mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1), __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
@ -209,35 +202,14 @@ __add_to_environ (const char *name, const char *value, const char *combined,
#endif #endif
{ {
#ifdef USE_TSEARCH #ifdef USE_TSEARCH
if (__glibc_unlikely (! use_alloca)) np = new_value;
np = new_value;
else
#endif #endif
{
np = malloc (varlen);
if (__glibc_unlikely (np == NULL))
{
UNLOCK;
return -1;
}
#ifdef USE_TSEARCH
memcpy (np, new_value, varlen);
#else
memcpy (np, name, namelen);
np[namelen] = '=';
memcpy (&np[namelen + 1], value, vallen);
#endif
}
/* And remember the value. */ /* And remember the value. */
STORE_VALUE (np); STORE_VALUE (np);
} }
#ifdef USE_TSEARCH #ifdef USE_TSEARCH
else else
{ free (new_value);
if (__glibc_unlikely (! use_alloca))
free (new_value);
}
#endif #endif
} }