NSS: Add sss_readrep_copy_string

There were many places in the client code where we were
duplicating a loop to copy data in from the response buffer. This
patch turns those loops into a function for easier maintenance and
easier-to-read *readrep() routines.

5 files changed, 131 insertions, 181 deletions

diff --git a/src/sss_client/common.c b/src/sss_client/common.c
index 94d15a52..998f7c8c 100644
--- a/src/sss_client/common.c
+++ b/src/sss_client/common.c
@@ -918,3 +918,33 @@ void sss_pam_lock(void) { return; }
 void sss_pam_unlock(void) { return; }
 #endif
 
+
+errno_t sss_readrep_copy_string(const char *in,
+                                size_t *offset,
+                                size_t *slen,
+                                size_t *dlen,
+                                char **out,
+                                size_t *size)
+{
+    size_t i = 0;
+    while (*slen > *offset && *dlen > 0) {
+        (*out)[i] = in[*offset];
+        if ((*out)[i] == '\0') break;
+        i++;
+        (*offset)++;
+        (*dlen)--;
+    }
+    if (*slen <= *offset) { /* premature end of buf */
+        return EBADMSG;
+    }
+    if (*dlen == 0) { /* not enough memory */
+        return ERANGE; /* not ENOMEM, ERANGE is what glibc looks for */
+    }
+    (*offset)++;
+    (*dlen)--;
+    if (size) {
+        *size = i;
+    }
+
+    return EOK;
+}
diff --git a/src/sss_client/nss_group.c b/src/sss_client/nss_group.c
index f5e715c8..7e5f79ad 100644
--- a/src/sss_client/nss_group.c
+++ b/src/sss_client/nss_group.c
@@ -78,8 +78,8 @@ struct sss_nss_gr_rep {
 static int sss_nss_getgr_readrep(struct sss_nss_gr_rep *pr,
                                  uint8_t *buf, size_t *len)
 {
-    size_t i, l, slen, ptmem, pad;
-    ssize_t dlen;
+    errno_t ret;
+    size_t i, l, slen, ptmem, pad, dlen, glen;
     char *sbuf;
     uint32_t mem_num;
     uint32_t c;
@@ -98,36 +98,19 @@ static int sss_nss_getgr_readrep(struct sss_nss_gr_rep *pr,
 
     pr->result->gr_name = &(pr->buffer[0]);
     i = 0;
-    while (slen > i && dlen > 0) {
-        pr->buffer[i] = sbuf[i];
-        if (pr->buffer[i] == '\0') break;
-        i++;
-        dlen--;
-    }
-    if (slen <= i) { /* premature end of buf */
-        return EBADMSG;
-    }
-    if (dlen <= 0) { /* not enough memory */
-        return ERANGE; /* not ENOMEM, ERANGE is what glibc looks for */
-    }
-    i++;
-    dlen--;
+
+    ret = sss_readrep_copy_string(sbuf, &i,
+                                  &slen, &dlen,
+                                  &pr->result->gr_name,
+                                  NULL);
+    if (ret != EOK) return ret;
 
     pr->result->gr_passwd = &(pr->buffer[i]);
-    while (slen > i && dlen > 0) {
-        pr->buffer[i] = sbuf[i];
-        if (pr->buffer[i] == '\0') break;
-        i++;
-        dlen--;
-    }
-    if (slen <= i) { /* premature end of buf */
-        return EBADMSG;
-    }
-    if (dlen <= 0) { /* not enough memory */
-        return ERANGE; /* not ENOMEM, ERANGE is what glibc looks for */
-    }
-    i++;
-    dlen--;
+    ret = sss_readrep_copy_string(sbuf, &i,
+                                  &slen, &dlen,
+                                  &pr->result->gr_passwd,
+                                  NULL);
+    if (ret != EOK) return ret;
 
     /* Make sure pr->buffer[i+pad] is 32 bit aligned */
     pad = 0;
@@ -147,22 +130,13 @@ static int sss_nss_getgr_readrep(struct sss_nss_gr_rep *pr,
 
     for (l = 0; l < mem_num; l++) {
         pr->result->gr_mem[l] = &(pr->buffer[ptmem]);
-        while ((slen > i) && (dlen > 0)) {
-            pr->buffer[ptmem] = sbuf[i];
-            if (pr->buffer[ptmem] == '\0') break;
-            i++;
-            dlen--;
-            ptmem++;
-        }
-        if (slen <= i) { /* premature end of buf */
-            return EBADMSG;
-        }
-        if (dlen <= 0) { /* not enough memory */
-            return ERANGE; /* not ENOMEM, ERANGE is what glibc looks for */
-        }
-        i++;
-        dlen--;
-        ptmem++;
+        ret = sss_readrep_copy_string(sbuf, &i,
+                                      &slen, &dlen,
+                                      &pr->result->gr_mem[l],
+                                      &glen);
+        if (ret != EOK) return ret;
+
+        ptmem += glen + 1;
     }
 
     *len = slen -i;
diff --git a/src/sss_client/nss_netgroup.c b/src/sss_client/nss_netgroup.c
index f63b1135..f72d547e 100644
--- a/src/sss_client/nss_netgroup.c
+++ b/src/sss_client/nss_netgroup.c
@@ -62,9 +62,10 @@ struct sss_nss_netgr_rep {
 static int sss_nss_getnetgr_readrep(struct sss_nss_netgr_rep *pr,
                                     uint8_t *buf, size_t *len)
 {
+    errno_t ret;
     char *sbuf;
-    size_t i, slen;
-    ssize_t dlen;
+    char *temp;
+    size_t i, slen, dlen, size;
     uint32_t type;
 
     if (*len < 6) {
@@ -84,92 +85,66 @@ static int sss_nss_getnetgr_readrep(struct sss_nss_netgr_rep *pr,
             pr->result->type = triple_val;
 
             /* Host value */
-            pr->result->val.triple.host = &(pr->buffer[i]);
-            while (slen > i && dlen > 0) {
-                pr->buffer[i] = sbuf[i];
-                if (pr->buffer[i] == '\0') break;
-                i++;
-                dlen--;
-            }
-            if (slen <= i) { /* premature end of buf */
-                return EBADMSG;
-            }
-            if (dlen <= 0) { /* not enough memory */
-                return ERANGE; /* not ENOMEM, ERANGE is what glibc looks for */
-            }
-            i++;
-            dlen--;
+            temp = &(pr->buffer[i]);
+            ret = sss_readrep_copy_string(sbuf, &i,
+                                          &slen, &dlen,
+                                          &temp,
+                                          &size);
+            if (ret != EOK) return ret;
 
             /* libc expects NULL instead of empty string */
-            if (strlen(pr->result->val.triple.host) == 0) {
+            if (size == 0) {
                 pr->result->val.triple.host = NULL;
+            } else {
+                pr->result->val.triple.host = temp;
             }
 
             /* User value */
-            pr->result->val.triple.user = &(pr->buffer[i]);
-            while (slen > i && dlen > 0) {
-                pr->buffer[i] = sbuf[i];
-                if (pr->buffer[i] == '\0') break;
-                i++;
-                dlen--;
-            }
-            if (slen <= i) { /* premature end of buf */
-                return EBADMSG;
-            }
-            if (dlen <= 0) { /* not enough memory */
-                return ERANGE; /* not ENOMEM, ERANGE is what glibc looks for */
-            }
-            i++;
-            dlen--;
+            temp = &(pr->buffer[i]);
+            ret = sss_readrep_copy_string(sbuf, &i,
+                                          &slen, &dlen,
+                                          &temp,
+                                          &size);
+            if (ret != EOK) return ret;
 
             /* libc expects NULL instead of empty string */
-            if (strlen(pr->result->val.triple.user) == 0) {
+            if (size == 0) {
                 pr->result->val.triple.user = NULL;
+            } else {
+                pr->result->val.triple.user = temp;
             }
 
             /* Domain value */
-            pr->result->val.triple.domain = &(pr->buffer[i]);
-            while (slen > i && dlen > 0) {
-                pr->buffer[i] = sbuf[i];
-                if (pr->buffer[i] == '\0') break;
-                i++;
-                dlen--;
-            }
-            if (slen <= i) { /* premature end of buf */
-                return EBADMSG;
-            }
-            if (dlen <= 0) { /* not enough memory */
-                return ERANGE; /* not ENOMEM, ERANGE is what glibc looks for */
-            }
-            i++;
-            dlen--;
+            temp = &(pr->buffer[i]);
+            ret = sss_readrep_copy_string(sbuf, &i,
+                                          &slen, &dlen,
+                                          &temp,
+                                          &size);
+            if (ret != EOK) return ret;
 
             /* libc expects NULL instead of empty string */
-            if (strlen(pr->result->val.triple.domain) == 0) {
+            if (size == 0) {
                 pr->result->val.triple.domain = NULL;
+            } else {
+                pr->result->val.triple.domain = temp;
             }
 
             break;
+
         case SSS_NETGR_REP_GROUP:
             pr->result->type = group_val;
 
-            pr->result->val.group = &(pr->buffer[i]);
-            while (slen > i && dlen > 0) {
-                pr->buffer[i] = sbuf[i];
-                if (pr->buffer[i] == '\0') break;
-                i++;
-                dlen--;
-            }
-            if (slen <= i) { /* premature end of buf */
-                return EBADMSG;
-            }
-            if (dlen <= 0) { /* not enough memory */
-                return ERANGE; /* not ENOMEM, ERANGE is what glibc looks for */
-            }
-            i++;
-            dlen--;
+            temp = &(pr->buffer[i]);
+            ret = sss_readrep_copy_string(sbuf, &i,
+                                          &slen, &dlen,
+                                          &temp,
+                                          NULL);
+            if (ret != EOK) return ret;
+
+            pr->result->val.group = temp;
 
             break;
+
         default:
             return EBADMSG;
     }
diff --git a/src/sss_client/nss_passwd.c b/src/sss_client/nss_passwd.c
index 15de5972..16124948 100644
--- a/src/sss_client/nss_passwd.c
+++ b/src/sss_client/nss_passwd.c
@@ -72,6 +72,7 @@ struct sss_nss_pw_rep {
 static int sss_nss_getpw_readrep(struct sss_nss_pw_rep *pr,
                                  uint8_t *buf, size_t *len)
 {
+    errno_t ret;
     size_t i, slen, dlen;
     char *sbuf;
     uint32_t c;
@@ -91,84 +92,42 @@ static int sss_nss_getpw_readrep(struct sss_nss_pw_rep *pr,
 
     i = 0;
     pr->result->pw_name = &(pr->buffer[i]);
-    while (slen > i && dlen > 0) {
-        pr->buffer[i] = sbuf[i];
-        if (pr->buffer[i] == '\0') break;
-        i++;
-        dlen--;
-    }
-    if (slen <= i) { /* premature end of buf */
-        return EBADMSG;
-    }
-    if (dlen <= 0) { /* not enough memory */
-        return ERANGE; /* not ENOMEM, ERANGE is what glibc looks for */
-    }
-    i++;
-    dlen--;
+
+    ret = sss_readrep_copy_string(sbuf, &i,
+                                  &slen, &dlen,
+                                  &pr->result->pw_name,
+                                  NULL);
+    if (ret != EOK) return ret;
 
     pr->result->pw_passwd = &(pr->buffer[i]);
-    while (slen > i && dlen > 0) {
-        pr->buffer[i] = sbuf[i];
-        if (pr->buffer[i] == '\0') break;
-        i++;
-        dlen--;
-    }
-    if (slen <= i) { /* premature end of buf */
-        return EBADMSG;
-    }
-    if (dlen <= 0) { /* not enough memory */
-        return ERANGE; /* not ENOMEM, ERANGE is what glibc looks for */
-    }
-    i++;
-    dlen--;
+    ret = sss_readrep_copy_string(sbuf, &i,
+                                  &slen, &dlen,
+                                  &pr->result->pw_passwd,
+                                  NULL);
+    if (ret != EOK) return ret;
 
     pr->result->pw_gecos = &(pr->buffer[i]);
-    while (slen > i && dlen > 0) {
-        pr->buffer[i] = sbuf[i];
-        if (pr->buffer[i] == '\0') break;
-        i++;
-        dlen--;
-    }
-    if (slen <= i) { /* premature end of buf */
-        return EBADMSG;
-    }
-    if (dlen <= 0) { /* not enough memory */
-        return ERANGE; /* not ENOMEM, ERANGE is what glibc looks for */
-    }
-    i++;
-    dlen--;
+    ret = sss_readrep_copy_string(sbuf, &i,
+                                  &slen, &dlen,
+                                  &pr->result->pw_gecos,
+                                  NULL);
+    if (ret != EOK) return ret;
+
 
     pr->result->pw_dir = &(pr->buffer[i]);
-    while (slen > i && dlen > 0) {
-        pr->buffer[i] = sbuf[i];
-        if (pr->buffer[i] == '\0') break;
-        i++;
-        dlen--;
-    }
-    if (slen <= i) { /* premature end of buf */
-        return EBADMSG;
-    }
-    if (dlen <= 0) { /* not enough memory */
-        return ERANGE; /* not ENOMEM, ERANGE is what glibc looks for */
-    }
-    i++;
-    dlen--;
+    ret = sss_readrep_copy_string(sbuf, &i,
+                                  &slen, &dlen,
+                                  &pr->result->pw_dir,
+                                  NULL);
+    if (ret != EOK) return ret;
 
     pr->result->pw_shell = &(pr->buffer[i]);
-    while (slen > i && dlen > 0) {
-        pr->buffer[i] = sbuf[i];
-        if (pr->buffer[i] == '\0') break;
-        i++;
-        dlen--;
-    }
-    if (slen <= i) { /* premature end of buf */
-        return EBADMSG;
-    }
-    if (dlen <= 0) { /* not enough memory */
-        return ERANGE; /* not ENOMEM, ERANGE is what glibc looks for */
-    }
-
-    *len = slen -i -1;
+    ret = sss_readrep_copy_string(sbuf, &i,
+                                  &slen, &dlen,
+                                  &pr->result->pw_shell,
+                                  NULL);
+    if (ret != EOK) return ret;
+    *len = slen - i;
 
     return 0;
 }
diff --git a/src/sss_client/sss_cli.h b/src/sss_client/sss_cli.h
index dc15ac13..c6e53e60 100644
--- a/src/sss_client/sss_cli.h
+++ b/src/sss_client/sss_cli.h
@@ -36,6 +36,11 @@
 typedef int errno_t;
 #endif
 
+
+#ifndef EOK
+#define EOK 0
+#endif
+
 #define SSS_NSS_PROTOCOL_VERSION 1
 #define SSS_PAM_PROTOCOL_VERSION 3
 #define SSS_SUDO_PROTOCOL_VERSION 0
@@ -508,4 +513,11 @@ void sss_nss_unlock(void);
 void sss_pam_lock(void);
 void sss_pam_unlock(void);
 
+errno_t sss_readrep_copy_string(const char *in,
+                                size_t *offset,
+                                size_t *slen,
+                                size_t *dlen,
+                                char **out,
+                                size_t *size);
+
 #endif /* _SSSCLI_H */