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

10 files changed, 40 insertions, 5 deletions

diff --git a/Makefile b/Makefile
index 7ab060f7c..cbaf05704 100644
--- a/Makefile
+++ b/Makefile
@@ -259,7 +259,7 @@ endif
 LIBBB_MSRC=libbb/messages.c
 LIBBB_MESSAGES= full_version name_too_long omitting_directory not_a_directory \
 memory_exhausted invalid_date invalid_option io_error dash_dash_help \
-write_error too_few_args name_longer_than_foo
+write_error too_few_args name_longer_than_foo unknown
 LIBBB_MOBJ=$(patsubst %,$(LIBBB)/%.o, $(LIBBB_MESSAGES))
 
 
diff --git a/cmdedit.c b/cmdedit.c
index ce5450032..ec9939312 100644
--- a/cmdedit.c
+++ b/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/hush.c b/hush.c
index abc8f6e60..9a2243a89 100644
--- a/hush.c
+++ b/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/include/libbb.h b/include/libbb.h
index 21af5688a..fde58b0a6 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -282,5 +282,6 @@ extern const char * const dash_dash_help;
 extern const char * const write_error;
 extern const char * const too_few_args;
 extern const char * const name_longer_than_foo;
+extern const char * const unknown;
 
 #endif /* __LIBBB_H__ */
diff --git a/lash.c b/lash.c
index 1d128355c..0129d6c02 100644
--- a/lash.c
+++ b/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);
diff --git a/libbb/libbb.h b/libbb/libbb.h
index 21af5688a..fde58b0a6 100644
--- a/libbb/libbb.h
+++ b/libbb/libbb.h
@@ -282,5 +282,6 @@ extern const char * const dash_dash_help;
 extern const char * const write_error;
 extern const char * const too_few_args;
 extern const char * const name_longer_than_foo;
+extern const char * const unknown;
 
 #endif /* __LIBBB_H__ */
diff --git a/libbb/messages.c b/libbb/messages.c
index 99c2bc9d5..910cb8fa2 100644
--- a/libbb/messages.c
+++ b/libbb/messages.c
@@ -58,4 +58,7 @@
 #ifdef L_name_longer_than_foo
 	const char * const name_longer_than_foo = "Names longer than %d chars not supported.";
 #endif
+#ifdef L_unknown
+	const char * const unknown = "(unknown)";
+#endif
 
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);