BDECFLAGS; de-__P()-ify, ANSIfy, use snprintf() instead of sprintf(),

especially on strings passed from argv; rename system() to exec_shell(),
and make it static; use strlcpy() and make sure it works; use proper
type (size_t) to be passed to malloc()/realloc().

Use getusershell() to make sure the SHELL environment variable passed is
safe to use.  Add new option -s to allow anal users to pass things like
perl; this option is here along with getusershell() checking since the
such checking is only intended to affect things like suidperl that might
call apply(1).

Reviewed by:	markm, jhb, C. Stephen Gunn <csg@waterspout.com>

1 files changed, 40 insertions, 23 deletions

diff --git a/usr.bin/apply/apply.c b/usr.bin/apply/apply.c
index 05e086d..fe72169 100644
--- a/usr.bin/apply/apply.c
+++ b/usr.bin/apply/apply.c
@@ -55,21 +55,23 @@ static const char rcsid[] =
 #include <string.h>
 #include <unistd.h>
 
-void	usage __P((void));
-int	system __P((const char *));
+void			usage (void);
+static int		exec_shell (const char *);
+
+static unsigned int	prespecified;
+static char		*shell;
 
 int
-main(argc, argv)
-	int argc;
-	char *argv[];
+main(int argc, char **argv)
 {
-	int ch, clen, debug, i, l, magic, n, nargs, rval;
+	int ch, debug, i, magic, n, nargs, rval;
+	size_t clen, l;
 	char *c, *cmd, *p, *q;
 
 	debug = 0;
 	magic = '%';		/* Default magic char is `%'. */
 	nargs = -1;
-	while ((ch = getopt(argc, argv, "a:d0123456789")) != -1)
+	while ((ch = getopt(argc, argv, "a:ds:0123456789")) != -1)
 		switch (ch) {
 		case 'a':
 			if (optarg[1] != '\0')
@@ -80,6 +82,10 @@ main(argc, argv)
 		case 'd':
 			debug = 1;
 			break;
+		case 's':
+			prespecified = 1;
+			shell = optarg;
+			break;
 		case '0': case '1': case '2': case '3': case '4':
 		case '5': case '6': case '7': case '8': case '9':
 			if (nargs != -1)
@@ -124,9 +130,9 @@ main(argc, argv)
 			nargs = 1;
 
 		p = cmd;
-		p += sprintf(cmd, "exec %s", argv[0]);
+		p += snprintf(cmd, sizeof(cmd), "exec %s", argv[0]);
 		for (i = 1; i <= nargs; i++)
-			p += sprintf(p, " %c%d", magic, i);
+			p += snprintf(p, sizeof(p), " %c%d", magic, i);
 
 		/*
 		 * If nargs set to the special value 0, eat a single
@@ -135,7 +141,7 @@ main(argc, argv)
 		if (nargs == 0)
 			nargs = 1;
 	} else {
-		(void)sprintf(cmd, "exec %s", argv[0]);
+		(void)snprintf(cmd, sizeof(cmd), "exec %s", argv[0]);
 		nargs = n;
 	}
 
@@ -165,7 +171,7 @@ main(argc, argv)
 		/* Expand command argv references. */
 		for (p = cmd, q = c; *p != '\0'; ++p)
 			if (p[0] == magic && isdigit(p[1]) && p[1] != '0')
-				q += sprintf(q, "%s", argv[(++p)[0] - '0']);
+				q += snprintf(q, sizeof(q), "%s", argv[(++p)[0] - '0']);
 			else
 				*q++ = *p;
 
@@ -176,7 +182,7 @@ main(argc, argv)
 		if (debug)
 			(void)printf("%s\n", c);
 		else
-			if (system(c))
+			if (exec_shell(c))
 				rval = 1;
 	}
 
@@ -187,28 +193,39 @@ main(argc, argv)
 }
 
 /*
- * system --
+ * exec_shell --
  * 	Private version of system(3).  Use the user's SHELL environment
  *	variable as the shell to execute.
  */
-int
-system(command)
-	const char *command;
+static int
+exec_shell(const char *command)
 {
-	static char *name, *shell;
+	static char *name;
+	char *tmpshell;
 	pid_t pid;
 	int omask, pstat;
 	sig_t intsave, quitsave;
+	unsigned int okshell = 0;
 
 	if (shell == NULL) {
 		if ((shell = getenv("SHELL")) == NULL)
-			shell = _PATH_BSHELL;
-		if ((name = strrchr(shell, '/')) == NULL)
-			name = shell;
-		else
+			if (strlcpy(shell, _PATH_BSHELL, sizeof(shell)) != strlen(shell))
+				err(1, "strlcpy() failed");
+		if ((name = strrchr(shell, '/')) == NULL) {
+			if (strlcpy(name, shell, sizeof(name)) != strlen(shell))
+				err(1, "strlcpy() failed");
+		} else {
 			++name;
+		}
 	}
-	if (!command)		/* just checking... */
+
+	/* Now double-check to make sure the shell is friendly */
+	if (!prespecified)
+		while((tmpshell = getusershell()) != NULL)
+			if (strcmp((const char *)tmpshell, (const char *)shell) == 0)
+				okshell = 1;
+
+	if (!command || !okshell)		/* just checking... */
 		return(1);
 
 	omask = sigblock(sigmask(SIGCHLD));
@@ -235,6 +252,6 @@ usage()
 {
 
 	(void)fprintf(stderr,
-	"usage: apply [-a magic] [-d] [-0123456789] command arguments ...\n");
+	"usage: apply [-a magic] [-d] [-s shell] [-0123456789] command arguments ...\n");
 	exit(1);
 }