Check for duplicate variables in the environment when setting a value

via setenv() or putenv().  OK miod@

2 files changed, 24 insertions, 11 deletions

diff --git a/src/lib/libc/stdlib/getenv.c b/src/lib/libc/stdlib/getenv.c
index 5aff11c61a..fd8482e9e3 100644
--- a/src/lib/libc/stdlib/getenv.c
+++ b/src/lib/libc/stdlib/getenv.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: getenv.c,v 1.9 2009/06/03 15:52:16 millert Exp $ */
+/*      $OpenBSD: getenv.c,v 1.10 2010/08/23 22:31:50 millert Exp $ */
 /*
  * Copyright (c) 1987, 1993
  *      The Regents of the University of California.  All rights reserved.
@@ -36,8 +36,9 @@ char *__findenv(const char *name, int len, int *offset);
 /*
  * __findenv --
  *      Returns pointer to value associated with name, if any, else NULL.
+ *      Starts searching within the environmental array at offset.
  *      Sets offset to be the offset of the name/value combination in the
- *      environmental array, for use by setenv(3) and unsetenv(3).
+ *      environmental array, for use by putenv(3), setenv(3) and unsetenv(3).
  *      Explicitly removes '=' in argument name.
  *
  *      This routine *should* be a static; don't use it.
@@ -52,7 +53,7 @@ __findenv(const char *name, int len, int *offset)
 
         if (name == NULL || environ == NULL)
                 return (NULL);
-        for (p = environ; (cp = *p) != NULL; ++p) {
+        for (p = environ + *offset; (cp = *p) != NULL; ++p) {
                 for (np = name, i = len; i && *cp; i--)
                         if (*cp++ != *np++)
                                 break;
@@ -71,7 +72,7 @@ __findenv(const char *name, int len, int *offset)
 char *
 getenv(const char *name)
 {
-        int offset;
+        int offset = 0;
         const char *np;
 
         for (np = name; *np && *np != '='; ++np)
diff --git a/src/lib/libc/stdlib/setenv.c b/src/lib/libc/stdlib/setenv.c
index 89d1e88911..089ab92d38 100644
--- a/src/lib/libc/stdlib/setenv.c
+++ b/src/lib/libc/stdlib/setenv.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: setenv.c,v 1.12 2010/06/29 04:09:34 naddy Exp $ */
+/*      $OpenBSD: setenv.c,v 1.13 2010/08/23 22:31:50 millert Exp $ */
 /*
  * Copyright (c) 1987 Regents of the University of California.
  * All rights reserved.
@@ -47,7 +47,7 @@ putenv(char *str)
 {
         char **P, *cp;
         size_t cnt;
-        int offset;
+        int offset = 0;
 
         for (cp = str; *cp && *cp != '='; ++cp)
                 ;
@@ -57,7 +57,13 @@ putenv(char *str)
         }
 
         if (__findenv(str, (int)(cp - str), &offset) != NULL) {
-                environ[offset] = str;
+                environ[offset++] = str;
+                /* could be set multiple times */
+                while (__findenv(str, (int)(cp - str), &offset)) {
+                        for (P = &environ[offset];; ++P)
+                                if (!(*P = *(P + 1)))
+                                        break;
+                }
                 return (0);
         }
 
@@ -84,9 +90,9 @@ putenv(char *str)
 int
 setenv(const char *name, const char *value, int rewrite)
 {
-        char *C;
+        char *C, **P;
         const char *np;
-        int l_value, offset;
+        int l_value, offset = 0;
 
         for (np = name; *np && *np != '='; ++np)
                 ;
@@ -99,6 +105,7 @@ setenv(const char *name, const char *value, int rewrite)
 
         l_value = strlen(value);
         if ((C = __findenv(name, (int)(np - name), &offset)) != NULL) {
+                int tmpoff = offset + 1;
                 if (!rewrite)
                         return (0);
 #if 0 /* XXX - existing entry may not be writable */
@@ -108,9 +115,14 @@ setenv(const char *name, const char *value, int rewrite)
                         return (0);
                 }
 #endif
+                /* could be set multiple times */
+                while (__findenv(name, (int)(np - name), &tmpoff)) {
+                        for (P = &environ[tmpoff];; ++P)
+                                if (!(*P = *(P + 1)))
+                                        break;
+                }
         } else {                                        /* create new slot */
                 size_t cnt;
-                char **P;
 
                 for (P = environ; *P != NULL; P++)
                         ;
@@ -143,7 +155,7 @@ unsetenv(const char *name)
 {
         char **P;
         const char *np;
-        int offset;
+        int offset = 0;
 
         if (!name || !*name) {
                 errno = EINVAL;