Fix a segfault in lash, hush, and cmdedit. Each of these used

xgetcwd, but did not check the return for a NULL, and then continued
to call strlen on the NULL when the cwd had been removed from under it.
 -Erik

3 files changed, 17 insertions, 2 deletions

diff --git a/shell/cmdedit.c b/shell/cmdedit.c
index ce5450032..ec9939312 100644
--- a/shell/cmdedit.c
+++ b/shell/cmdedit.c
@@ -355,6 +355,10 @@ static void parse_prompt(const char *prmt_ptr)
         char  c;
         char *pbuf;
 
+        if (!pwd_buf) {
+                pwd_buf=unknown;
+        }
+
         while (*prmt_ptr) {
                 pbuf    = buf;
                 pbuf[1] = 0;
diff --git a/shell/hush.c b/shell/hush.c
index abc8f6e60..9a2243a89 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -429,6 +429,8 @@ static int builtin_cd(struct child_prog *child)
                 return EXIT_FAILURE;
         }
         cwd = xgetcwd(cwd);
+        if (!cwd)
+                cwd = unknown;
         return EXIT_SUCCESS;
 }
 
@@ -568,6 +570,8 @@ static int builtin_jobs(struct child_prog *child)
 static int builtin_pwd(struct child_prog *dummy)
 {
         cwd = xgetcwd(cwd);
+        if (!cwd)
+                cwd = unknown;
         puts(cwd);
         return EXIT_SUCCESS;
 }
@@ -2307,6 +2311,8 @@ int shell_main(int argc, char **argv)
         
         /* initialize the cwd -- this is never freed...*/
         cwd = xgetcwd(0);
+        if (!cwd)
+                cwd = unknown;
 #ifdef BB_FEATURE_COMMAND_EDITING
         cmdedit_set_initial_prompt();
 #else
diff --git a/shell/lash.c b/shell/lash.c
index 1d128355c..0129d6c02 100644
--- a/shell/lash.c
+++ b/shell/lash.c
@@ -297,7 +297,8 @@ static int builtin_cd(struct child_prog *child)
                 return EXIT_FAILURE;
         }
         cwd = xgetcwd(cwd);
-
+        if (!cwd)
+                cwd = unknown;
         return EXIT_SUCCESS;
 }
 
@@ -412,6 +413,9 @@ static int builtin_jobs(struct child_prog *child)
 /* built-in 'pwd' handler */
 static int builtin_pwd(struct child_prog *dummy)
 {
+        cwd = xgetcwd(cwd);
+        if (!cwd)
+                cwd = unknown;
         printf( "%s\n", cwd);
         return EXIT_SUCCESS;
 }
@@ -1827,7 +1831,6 @@ void free_memory(void)
 {
         if (cwd) {
                 free(cwd);
-                cwd = NULL;
         }
         if (local_pending_command)
                 free(local_pending_command);
@@ -1919,6 +1922,8 @@ int shell_main(int argc_l, char **argv_l)
 
         /* initialize the cwd -- this is never freed...*/
         cwd = xgetcwd(0);
+        if (!cwd)
+                cwd = unknown;
 
 #ifdef BB_FEATURE_CLEAN_UP
         atexit(free_memory);