mirror of
git://sourceware.org/git/glibc.git
synced 2025-03-31 14:01:18 +08:00
nss_dns: Split getanswer_ptr from getanswer_r
And expand the use of name_ok and qtype in getanswer_ptr (the former also in getanswer_r). After further cleanups, not much code will be shared between the two functions. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org> (cherry picked from commit 0dcc43e9981005540bf39dc7bf33fbab62cf9e84)
This commit is contained in:
Florian Weimer
parent
f0e9657067
commit
b714ab7e3c
@ -116,6 +116,11 @@ static enum nss_status getanswer_r (struct resolv_context *ctx,
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struct hostent *result, char *buffer,
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size_t buflen, int *errnop, int *h_errnop,
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int map, int32_t *ttlp, char **canonp);
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static enum nss_status getanswer_ptr (const querybuf *answer, int anslen,
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const char *qname,
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struct hostent *result, char *buffer,
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size_t buflen, int *errnop,
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int *h_errnop, int32_t *ttlp);
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static enum nss_status gaih_getanswer (const querybuf *answer1, int anslen1,
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const querybuf *answer2, int anslen2,
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@ -561,9 +566,8 @@ _nss_dns_gethostbyaddr2_r (const void *addr, socklen_t len, int af,
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return errno == ECONNREFUSED ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
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}
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status = getanswer_r
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(ctx, host_buffer.buf, n, qbuf, T_PTR, result, buffer, buflen,
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errnop, h_errnop, 0 /* XXX */, ttlp, NULL);
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status = getanswer_ptr (host_buffer.buf, n, qbuf, result,
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buffer, buflen, errnop, h_errnop, ttlp);
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if (host_buffer.buf != orig_host_buffer)
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free (host_buffer.buf);
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if (status != NSS_STATUS_SUCCESS)
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@ -659,8 +663,6 @@ getanswer_r (struct resolv_context *ctx,
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int haveanswer, had_error;
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char *bp, **ap, **hap;
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char tbuf[MAXDNAME];
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const char *tname;
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int (*name_ok) (const char *);
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u_char packtmp[NS_MAXCDNAME];
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int have_to_map = 0;
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uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct host_data);
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@ -679,22 +681,8 @@ getanswer_r (struct resolv_context *ctx,
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if (buflen - sizeof (struct host_data) != linebuflen)
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linebuflen = INT_MAX;
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tname = qname;
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result->h_name = NULL;
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end_of_message = answer->buf + anslen;
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switch (qtype)
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{
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case T_A:
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case T_AAAA:
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name_ok = __libc_res_hnok;
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break;
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case T_PTR:
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name_ok = __libc_res_dnok;
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break;
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default:
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*errnop = ENOENT;
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return NSS_STATUS_UNAVAIL; /* XXX should be abort(); */
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}
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/*
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* find first satisfactory answer
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@ -729,7 +717,7 @@ getanswer_r (struct resolv_context *ctx,
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*h_errnop = NO_RECOVERY;
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return NSS_STATUS_UNAVAIL;
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}
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if (__glibc_unlikely (name_ok (bp) == 0))
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if (__glibc_unlikely (__libc_res_hnok (bp) == 0))
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{
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errno = EBADMSG;
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*errnop = EBADMSG;
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@ -783,7 +771,7 @@ getanswer_r (struct resolv_context *ctx,
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n = -1;
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}
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if (__glibc_unlikely (n < 0 || (*name_ok) (bp) == 0))
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if (__glibc_unlikely (n < 0 || __libc_res_hnok (bp) == 0))
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{
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++had_error;
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continue;
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@ -816,7 +804,7 @@ getanswer_r (struct resolv_context *ctx,
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continue; /* XXX - had_error++ ? */
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}
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if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME)
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if (type == T_CNAME)
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{
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/* A CNAME could also have a TTL entry. */
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if (ttlp != NULL && ttl < *ttlp)
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@ -826,7 +814,7 @@ getanswer_r (struct resolv_context *ctx,
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continue;
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n = __libc_dn_expand (answer->buf, end_of_message, cp,
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tbuf, sizeof tbuf);
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if (__glibc_unlikely (n < 0 || (*name_ok) (tbuf) == 0))
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if (__glibc_unlikely (n < 0 || __libc_res_hnok (tbuf) == 0))
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{
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++had_error;
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continue;
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@ -857,35 +845,6 @@ getanswer_r (struct resolv_context *ctx,
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continue;
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}
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if (qtype == T_PTR && type == T_CNAME)
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{
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/* A CNAME could also have a TTL entry. */
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if (ttlp != NULL && ttl < *ttlp)
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*ttlp = ttl;
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n = __libc_dn_expand (answer->buf, end_of_message, cp,
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tbuf, sizeof tbuf);
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if (__glibc_unlikely (n < 0 || __libc_res_dnok (tbuf) == 0))
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{
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++had_error;
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continue;
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}
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cp += n;
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/* Get canonical name. */
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n = strlen (tbuf) + 1; /* For the \0. */
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if (__glibc_unlikely (n > linebuflen))
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goto too_small;
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if (__glibc_unlikely (n >= MAXHOSTNAMELEN))
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{
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++had_error;
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continue;
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}
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tname = bp;
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bp = __mempcpy (bp, tbuf, n); /* Cannot overflow. */
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linebuflen -= n;
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continue;
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}
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if (type == T_A && qtype == T_AAAA && map)
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have_to_map = 1;
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else if (__glibc_unlikely (type != qtype))
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@ -896,35 +855,6 @@ getanswer_r (struct resolv_context *ctx,
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switch (type)
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{
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case T_PTR:
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if (__glibc_unlikely (__strcasecmp (tname, bp) != 0))
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{
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cp += n;
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continue; /* XXX - had_error++ ? */
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}
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n = __ns_name_unpack (answer->buf, end_of_message, cp,
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packtmp, sizeof packtmp);
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if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
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{
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if (__glibc_unlikely (errno == EMSGSIZE))
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goto too_small;
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n = -1;
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}
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if (__glibc_unlikely (n < 0 || __libc_res_hnok (bp) == 0))
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{
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++had_error;
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break;
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}
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if (ttlp != NULL && ttl < *ttlp)
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*ttlp = ttl;
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/* bind would put multiple PTR records as aliases, but we don't do
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that. */
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result->h_name = bp;
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*h_errnop = NETDB_SUCCESS;
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return NSS_STATUS_SUCCESS;
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case T_A:
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case T_AAAA:
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if (__glibc_unlikely (__strcasecmp (result->h_name, bp) != 0))
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@ -1030,6 +960,292 @@ getanswer_r (struct resolv_context *ctx,
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? NSS_STATUS_NOTFOUND : NSS_STATUS_TRYAGAIN);
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}
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static enum nss_status
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getanswer_ptr (const querybuf *answer, int anslen, const char *qname,
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struct hostent *result, char *buffer, size_t buflen,
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int *errnop, int *h_errnop, int32_t *ttlp)
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{
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struct host_data
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{
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char *aliases[MAX_NR_ALIASES];
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unsigned char host_addr[16]; /* IPv4 or IPv6 */
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char *h_addr_ptrs[0];
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} *host_data;
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int linebuflen;
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const HEADER *hp;
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const u_char *end_of_message, *cp;
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int n, ancount, qdcount;
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int haveanswer, had_error;
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char *bp, **ap, **hap;
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char tbuf[MAXDNAME];
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const char *tname;
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u_char packtmp[NS_MAXCDNAME];
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uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct host_data);
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buffer += pad;
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buflen = buflen > pad ? buflen - pad : 0;
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if (__glibc_unlikely (buflen < sizeof (struct host_data)))
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{
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/* The buffer is too small. */
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too_small:
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*errnop = ERANGE;
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*h_errnop = NETDB_INTERNAL;
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return NSS_STATUS_TRYAGAIN;
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}
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host_data = (struct host_data *) buffer;
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linebuflen = buflen - sizeof (struct host_data);
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if (buflen - sizeof (struct host_data) != linebuflen)
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linebuflen = INT_MAX;
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tname = qname;
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result->h_name = NULL;
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end_of_message = answer->buf + anslen;
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/*
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* find first satisfactory answer
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*/
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hp = &answer->hdr;
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ancount = ntohs (hp->ancount);
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qdcount = ntohs (hp->qdcount);
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cp = answer->buf + HFIXEDSZ;
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if (__glibc_unlikely (qdcount != 1))
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{
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*h_errnop = NO_RECOVERY;
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return NSS_STATUS_UNAVAIL;
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}
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if (sizeof (struct host_data) + (ancount + 1) * sizeof (char *) >= buflen)
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goto too_small;
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bp = (char *) &host_data->h_addr_ptrs[ancount + 1];
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linebuflen -= (ancount + 1) * sizeof (char *);
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n = __ns_name_unpack (answer->buf, end_of_message, cp,
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packtmp, sizeof packtmp);
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if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
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{
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if (__glibc_unlikely (errno == EMSGSIZE))
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goto too_small;
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n = -1;
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}
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if (__glibc_unlikely (n < 0))
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{
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*errnop = errno;
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*h_errnop = NO_RECOVERY;
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return NSS_STATUS_UNAVAIL;
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}
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if (__glibc_unlikely (__libc_res_dnok (bp) == 0))
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{
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errno = EBADMSG;
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*errnop = EBADMSG;
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*h_errnop = NO_RECOVERY;
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return NSS_STATUS_UNAVAIL;
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}
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cp += n + QFIXEDSZ;
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ap = host_data->aliases;
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*ap = NULL;
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result->h_aliases = host_data->aliases;
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hap = host_data->h_addr_ptrs;
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*hap = NULL;
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result->h_addr_list = host_data->h_addr_ptrs;
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haveanswer = 0;
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had_error = 0;
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while (ancount-- > 0 && cp < end_of_message && had_error == 0)
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{
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int type, class;
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n = __ns_name_unpack (answer->buf, end_of_message, cp,
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packtmp, sizeof packtmp);
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if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
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{
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if (__glibc_unlikely (errno == EMSGSIZE))
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goto too_small;
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n = -1;
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}
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if (__glibc_unlikely (n < 0 || __libc_res_dnok (bp) == 0))
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{
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++had_error;
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continue;
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}
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cp += n; /* name */
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if (__glibc_unlikely (cp + 10 > end_of_message))
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{
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++had_error;
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continue;
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}
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NS_GET16 (type, cp);
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NS_GET16 (class, cp);
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int32_t ttl;
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NS_GET32 (ttl, cp);
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NS_GET16 (n, cp); /* RDATA length. */
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if (end_of_message - cp < n)
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{
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/* RDATA extends beyond the end of the packet. */
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++had_error;
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continue;
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}
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if (__glibc_unlikely (class != C_IN))
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{
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/* XXX - debug? syslog? */
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cp += n;
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continue; /* XXX - had_error++ ? */
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}
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if (type == T_CNAME)
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{
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/* A CNAME could also have a TTL entry. */
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if (ttlp != NULL && ttl < *ttlp)
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*ttlp = ttl;
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n = __libc_dn_expand (answer->buf, end_of_message, cp,
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tbuf, sizeof tbuf);
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if (__glibc_unlikely (n < 0 || __libc_res_dnok (tbuf) == 0))
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{
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++had_error;
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continue;
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}
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cp += n;
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/* Get canonical name. */
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n = strlen (tbuf) + 1; /* For the \0. */
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if (__glibc_unlikely (n > linebuflen))
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goto too_small;
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if (__glibc_unlikely (n >= MAXHOSTNAMELEN))
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{
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++had_error;
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continue;
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}
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tname = bp;
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bp = __mempcpy (bp, tbuf, n); /* Cannot overflow. */
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linebuflen -= n;
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continue;
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}
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switch (type)
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{
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case T_PTR:
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if (__glibc_unlikely (__strcasecmp (tname, bp) != 0))
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{
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cp += n;
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continue; /* XXX - had_error++ ? */
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}
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n = __ns_name_unpack (answer->buf, end_of_message, cp,
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packtmp, sizeof packtmp);
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if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
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{
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if (__glibc_unlikely (errno == EMSGSIZE))
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goto too_small;
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n = -1;
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}
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if (__glibc_unlikely (n < 0 || __libc_res_hnok (bp) == 0))
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{
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++had_error;
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break;
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}
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if (ttlp != NULL && ttl < *ttlp)
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*ttlp = ttl;
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/* bind would put multiple PTR records as aliases, but we don't do
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that. */
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result->h_name = bp;
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*h_errnop = NETDB_SUCCESS;
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return NSS_STATUS_SUCCESS;
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case T_A:
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case T_AAAA:
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if (__glibc_unlikely (__strcasecmp (result->h_name, bp) != 0))
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{
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cp += n;
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continue; /* XXX - had_error++ ? */
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}
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/* Stop parsing at a record whose length is incorrect. */
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if (n != rrtype_to_rdata_length (type))
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{
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++had_error;
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break;
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}
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/* Skip records of the wrong type. */
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if (n != result->h_length)
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{
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cp += n;
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continue;
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}
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if (!haveanswer)
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{
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int nn;
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/* We compose a single hostent out of the entire chain of
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entries, so the TTL of the hostent is essentially the lowest
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TTL in the chain. */
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if (ttlp != NULL && ttl < *ttlp)
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*ttlp = ttl;
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result->h_name = bp;
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nn = strlen (bp) + 1; /* for the \0 */
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bp += nn;
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linebuflen -= nn;
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}
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/* Provide sufficient alignment for both address
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families. */
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enum { align = 4 };
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_Static_assert ((align % __alignof__ (struct in_addr)) == 0,
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"struct in_addr alignment");
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_Static_assert ((align % __alignof__ (struct in6_addr)) == 0,
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"struct in6_addr alignment");
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{
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char *new_bp = PTR_ALIGN_UP (bp, align);
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linebuflen -= new_bp - bp;
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bp = new_bp;
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}
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if (__glibc_unlikely (n > linebuflen))
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goto too_small;
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bp = __mempcpy (*hap++ = bp, cp, n);
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cp += n;
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linebuflen -= n;
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break;
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default:
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cp += n;
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continue; /* XXX - had_error++ ? */
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}
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if (had_error == 0)
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++haveanswer;
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}
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if (haveanswer > 0)
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{
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*ap = NULL;
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*hap = NULL;
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if (result->h_name == NULL)
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{
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n = strlen (qname) + 1; /* For the \0. */
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if (n > linebuflen)
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goto too_small;
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if (n >= MAXHOSTNAMELEN)
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goto no_recovery;
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result->h_name = bp;
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bp = __mempcpy (bp, qname, n); /* Cannot overflow. */
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linebuflen -= n;
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}
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*h_errnop = NETDB_SUCCESS;
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return NSS_STATUS_SUCCESS;
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}
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no_recovery:
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*h_errnop = NO_RECOVERY;
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*errnop = ENOENT;
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return NSS_STATUS_TRYAGAIN;
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}
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static enum nss_status
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gaih_getanswer_slice (const querybuf *answer, int anslen, const char *qname,
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