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nscd_getgr_r: Use struct scratch_buffer instead of extend_alloca 

The lack of alloca accounting means that the old code could run out of
stack space if multiple retries are needed.
This commit is contained in:
Florian Weimer 2015-04-08 20:58:58 +02:00
parent c6ee40da8b
commit 561052ad35
2 changed files with 10 additions and 9 deletions
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1
ChangeLog
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@ -12,6 +12,7 @@
* nis/nss_compat/compat-initgroups.c (_nss_compat_initgroups_dyn):
Rewrite to use struct scratch_buffer instead of extend_alloca.
* inet/getnameinfo.c (nrl_domainname, getnameinfo): Likewise.
* nscd/nscd_getgr_r.c (nscd_getgr_r): Likewise.
2015-04-08 Joseph Myers <joseph@codesourcery.com>

18
nscd/nscd_getgr_r.c
View File

@ -31,6 +31,7 @@
#include <sys/un.h>
#include <not-cancel.h>
#include <_itoa.h>
#include <scratch_buffer.h>
#include "nscd-client.h"
#include "nscd_proto.h"
@ -89,7 +90,8 @@ nscd_getgr_r (const char *key, size_t keylen, request_type type,
int gc_cycle;
int nretries = 0;
const uint32_t *len = NULL;
size_t lensize = 0;
struct scratch_buffer lenbuf;
scratch_buffer_init (&lenbuf);
/* If the mapping is available, try to search there instead of
communicating with the nscd. */
@ -200,14 +202,10 @@ nscd_getgr_r (const char *key, size_t keylen, request_type type,
else
{
/* Allocate array to store lengths. */
if (lensize == 0)
{
lensize = gr_resp.gr_mem_cnt * sizeof (uint32_t);
len = (uint32_t *) alloca (lensize);
}
else if (gr_resp.gr_mem_cnt * sizeof (uint32_t) > lensize)
len = extend_alloca (len, lensize,
gr_resp.gr_mem_cnt * sizeof (uint32_t));
if (!scratch_buffer_set_array_size
(&lenbuf, gr_resp.gr_mem_cnt, sizeof (uint32_t)))
goto out_close;
len = lenbuf.data;
vec[0].iov_base = (void *) len;
vec[0].iov_len = gr_resp.gr_mem_cnt * sizeof (uint32_t);
@ -326,5 +324,7 @@ nscd_getgr_r (const char *key, size_t keylen, request_type type,
goto retry;
}
scratch_buffer_free (&lenbuf);
return retval;
}