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dns lookups: protect against cancellation and fix incorrect error codes

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This commit is contained in:
Rich Felker
2011-04-18 21:35:14 -04:00
parent 75a0be1f65
commit 43ee4df338
1 changed files with 10 additions and 4 deletions
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14
src/network/__dns.c
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@ -11,6 +11,7 @@
#include <time.h> #include <time.h>
#include <ctype.h> #include <ctype.h>
#include <unistd.h> #include <unistd.h>
#include <pthread.h>
#include "__dns.h" #include "__dns.h"
#include "stdio_impl.h" #include "stdio_impl.h"
@ -42,14 +43,15 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
struct timeval tv; struct timeval tv;
fd_set fds; fd_set fds;
int id; int id;
int cs;
/* Construct query template - RR and ID will be filled later */ /* Construct query template - RR and ID will be filled later */
if (strlen(name)-1 >= 254U) return -1; if (strlen(name)-1 >= 254U) return EAI_NONAME;
q[2] = q[5] = 1; q[2] = q[5] = 1;
strcpy((char *)q+13, name); strcpy((char *)q+13, name);
for (i=13; q[i]; i=j+1) { for (i=13; q[i]; i=j+1) {
for (j=i; q[j] && q[j] != '.'; j++); for (j=i; q[j] && q[j] != '.'; j++);
if (j-i-1u > 62u) return -1; if (j-i-1u > 62u) return EAI_NONAME;
q[i-1] = j-i; q[i-1] = j-i;
} }
q[i+3] = 1; q[i+3] = 1;
@ -80,12 +82,14 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
sl = sizeof sa.sin; sl = sizeof sa.sin;
} }
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
/* Get local address and open/bind a socket */ /* Get local address and open/bind a socket */
sa.sin.sin_family = family; sa.sin.sin_family = family;
fd = socket(family, SOCK_DGRAM, 0); fd = socket(family, SOCK_DGRAM, 0);
if (bind(fd, (void *)&sa, sl) < 0) { if (bind(fd, (void *)&sa, sl) < 0) {
close(fd); errcode = EAI_SYSTEM;
return -1; goto out;
} }
/* Nonblocking to work around Linux UDP select bug */ /* Nonblocking to work around Linux UDP select bug */
fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK); fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK);
@ -140,7 +144,9 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
/* Check to see if we have answers to all queries */ /* Check to see if we have answers to all queries */
if (got+failed == rrcnt) break; if (got+failed == rrcnt) break;
} }
out:
close(fd); close(fd);
pthread_setcancelstate(cs, 0);
/* Return the number of results, or an error code if none */ /* Return the number of results, or an error code if none */
if (got) return got; if (got) return got;