| Message ID | 20230629151509.815494-1-josimmon@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] setenv.c: Get rid of alloca. | expand |
On 29/06/23 12:15, Joe Simmons-Talbott via Libc-alpha wrote: > Use malloc rather than alloca to avoid potential stack overflow. LGTM, thanks. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > --- > Changes to v2: > * Remove left-over include of scratch_buffer.h which is no longer > needed. > > stdlib/setenv.c | 40 ++++++---------------------------------- > 1 file changed, 6 insertions(+), 34 deletions(-) > > diff --git a/stdlib/setenv.c b/stdlib/setenv.c > index ba5257d3bf..cc71287fcc 100644 > --- a/stdlib/setenv.c > +++ b/stdlib/setenv.c > @@ -182,18 +182,11 @@ __add_to_environ (const char *name, const char *value, const char *combined, > { > const size_t varlen = namelen + 1 + vallen; > #ifdef USE_TSEARCH > - char *new_value; > - int use_alloca = __libc_use_alloca (varlen); > - if (__builtin_expect (use_alloca, 1)) > - new_value = (char *) alloca (varlen); > - else > + char *new_value = malloc (varlen); > + if (new_value == NULL) > { > - new_value = malloc (varlen); > - if (new_value == NULL) > - { > - UNLOCK; > - return -1; > - } > + UNLOCK; > + return -1; > } > # ifdef _LIBC > __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 > { > #ifdef USE_TSEARCH > - if (__glibc_unlikely (! use_alloca)) > - np = new_value; > - else > + np = new_value; > #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. */ > STORE_VALUE (np); > } > #ifdef USE_TSEARCH > else > - { > - if (__glibc_unlikely (! use_alloca)) > - free (new_value); > - } > + free (new_value); > #endif > } >
diff --git a/stdlib/setenv.c b/stdlib/setenv.c index ba5257d3bf..cc71287fcc 100644 --- a/stdlib/setenv.c +++ b/stdlib/setenv.c @@ -182,18 +182,11 @@ __add_to_environ (const char *name, const char *value, const char *combined, { const size_t varlen = namelen + 1 + vallen; #ifdef USE_TSEARCH - char *new_value; - int use_alloca = __libc_use_alloca (varlen); - if (__builtin_expect (use_alloca, 1)) - new_value = (char *) alloca (varlen); - else + char *new_value = malloc (varlen); + if (new_value == NULL) { - new_value = malloc (varlen); - if (new_value == NULL) - { - UNLOCK; - return -1; - } + UNLOCK; + return -1; } # ifdef _LIBC __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 { #ifdef USE_TSEARCH - if (__glibc_unlikely (! use_alloca)) - np = new_value; - else + np = new_value; #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. */ STORE_VALUE (np); } #ifdef USE_TSEARCH else - { - if (__glibc_unlikely (! use_alloca)) - free (new_value); - } + free (new_value); #endif }
Use malloc rather than alloca to avoid potential stack overflow. --- Changes to v2: * Remove left-over include of scratch_buffer.h which is no longer needed. stdlib/setenv.c | 40 ++++++---------------------------------- 1 file changed, 6 insertions(+), 34 deletions(-)