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getaddrinfo: Always allocate canonical name on the heap

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A further simplification could eliminate the canon variable in
gaih_inet and replace it with canonbuf.  However, canonbuf is
used as a flag in the nscd code, which makes this somewhat
non-straightforward.
This commit is contained in:
Florian Weimer 2017-06-02 14:54:56 +02:00
parent 91b6eb1140
commit 673cb072a4
2 changed files with 47 additions and 67 deletions
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5
ChangeLog
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@ -1,3 +1,8 @@
2017-06-02 Florian Weimer <fweimer@redhat.com>
* sysdeps/posix/getaddrinfo.c (getcanonname): New function.
(gaih_inet): Remove malloc_canonbuf variable. Call getcanonname.
2017-06-02 Florian Weimer <fweimer@redhat.com>
* malloc/Makefile (routines): Add dynarray_at_failure,

109
sysdeps/posix/getaddrinfo.c
View File

@ -308,6 +308,30 @@ typedef enum nss_status (*nss_getcanonname_r)
int *errnop, int *h_errnop);
extern service_user *__nss_hosts_database attribute_hidden;
/* This function is called if a canonical name is requested, but if
the service function did not provide it. It tries to obtain the
name using getcanonname_r from the same service NIP. If the name
cannot be canonicalized, return a copy of NAME. Return NULL on
memory allocation failure. The returned string is allocated on the
heap; the caller has to free it. */
static char *
getcanonname (service_user *nip, struct gaih_addrtuple *at, const char *name)
{
nss_getcanonname_r cfct = __nss_lookup_function (nip, "getcanonname_r");
char *s = (char *) name;
if (cfct != NULL)
{
char buf[256];
int herrno;
int rc;
if (DL_CALL_FCT (cfct, (at->name ?: name, buf, sizeof (buf),
&s, &rc, &herrno)) != NSS_STATUS_SUCCESS)
/* If the canonical name cannot be determined, use the passed
string. */
s = (char *) name;
}
return strdup (name);
}
static int
gaih_inet (const char *name, const struct gaih_service *service,
@ -443,7 +467,6 @@ gaih_inet (const char *name, const struct gaih_service *service,
bool malloc_name = false;
struct gaih_addrtuple *addrmem = NULL;
bool malloc_canonbuf = false;
char *canonbuf = NULL;
int result = 0;
@ -702,22 +725,13 @@ gaih_inet (const char *name, const struct gaih_service *service,
(*pat)->name = NULL;
else if (canonbuf == NULL)
{
size_t canonlen = strlen (air->canon) + 1;
if ((req->ai_flags & AI_CANONIDN) != 0
&& __libc_use_alloca (alloca_used + canonlen))
canonbuf = alloca_account (canonlen, alloca_used);
else
canonbuf = strdup (air->canon);
if (canonbuf == NULL)
{
canonbuf = malloc (canonlen);
if (canonbuf == NULL)
{
result = -EAI_MEMORY;
goto free_and_return;
}
malloc_canonbuf = true;
result = -EAI_MEMORY;
goto free_and_return;
}
canon = (*pat)->name = memcpy (canonbuf, air->canon,
canonlen);
canon = (*pat)->name = canonbuf;
}
if (air->family[i] == AF_INET
@ -924,55 +938,16 @@ gaih_inet (const char *name, const struct gaih_service *service,
if ((req->ai_flags & AI_CANONNAME) != 0
&& canon == NULL)
{
/* If we need the canonical name, get it
from the same service as the result. */
nss_getcanonname_r cfct;
int herrno;
cfct = __nss_lookup_function (nip,
"getcanonname_r");
if (cfct != NULL)
canonbuf = getcanonname (nip, at, name);
if (canonbuf == NULL)
{
const size_t max_fqdn_len = 256;
if ((req->ai_flags & AI_CANONIDN) != 0
&& __libc_use_alloca (alloca_used
+ max_fqdn_len))
canonbuf = alloca_account (max_fqdn_len,
alloca_used);
else
{
canonbuf = malloc (max_fqdn_len);
if (canonbuf == NULL)
{
_res.options
|= old_res_options
& DEPRECATED_RES_USE_INET6;
result = -EAI_MEMORY;
goto free_and_return;
}
malloc_canonbuf = true;
}
char *s;
if (DL_CALL_FCT (cfct, (at->name ?: name,
canonbuf,
max_fqdn_len,
&s, &rc, &herrno))
== NSS_STATUS_SUCCESS)
canon = s;
else
{
/* If the canonical name cannot be
determined, use the passed in
string. */
if (malloc_canonbuf)
{
free (canonbuf);
malloc_canonbuf = false;
}
canon = name;
}
_res.options
|= old_res_options
& DEPRECATED_RES_USE_INET6;
result = -EAI_MEMORY;
goto free_and_return;
}
canon = canonbuf;
}
status = NSS_STATUS_SUCCESS;
}
@ -1118,9 +1093,10 @@ gaih_inet (const char *name, const struct gaih_service *service,
#ifdef HAVE_LIBIDN
make_copy:
#endif
if (malloc_canonbuf)
/* We already allocated the string using malloc. */
malloc_canonbuf = false;
if (canonbuf != NULL)
/* We already allocated the string using malloc, but
the buffer is now owned by canon. */
canonbuf = NULL;
else
{
canon = __strdup (canon);
@ -1215,8 +1191,7 @@ gaih_inet (const char *name, const struct gaih_service *service,
if (malloc_name)
free ((char *) name);
free (addrmem);
if (malloc_canonbuf)
free (canonbuf);
free (canonbuf);
return result;
}