Allow user to omit font size specification when loading a font. In addition

the following fixes had been made:

- check the size of the font being loaded and compare it with possible sizes
  to minimise possibility of loading something that is not a fontfile at all
  and turning console screen into garbage;

- prevent buffer overflow (and coredump as a result ) when loading valid
  uuencoded file with size that exceeds allocated buffer;

- correct and improve several error messages.

Approved by:	-audit, -hackers (silently)

4 files changed, 131 insertions, 43 deletions

diff --git a/usr.sbin/vidcontrol/decode.c b/usr.sbin/vidcontrol/decode.c
index 1990595..3c6b467 100644
--- a/usr.sbin/vidcontrol/decode.c
+++ b/usr.sbin/vidcontrol/decode.c
@@ -35,10 +35,11 @@ static const char rcsid[] =
 #include <string.h>
 #include "decode.h"
 
-int decode(FILE *fd, char *buffer)
+int decode(FILE *fd, char *buffer, int len)
 {
-	int n, pos = 0;
-	char *p;
+	int n, pos = 0, tpos;
+	char *bp, *p;
+	char tbuffer[3];
 	char temp[128];
 
 #define	DEC(c)	(((c) - ' ') & 0x3f)
@@ -48,31 +49,49 @@ int decode(FILE *fd, char *buffer)
 			return(0);
 	} while (strncmp(temp, "begin ", 6));
 	sscanf(temp, "begin %o %s", &n, temp);
+	bp = buffer;
 	for (;;) {
 		if (!fgets(p = temp, sizeof(temp), fd))
 			return(0);
 		if ((n = DEC(*p)) <= 0)
 			break;
-		for (++p; n > 0; p += 4, n -= 3)
+		for (++p; n > 0; p += 4, n -= 3) {
+			tpos = 0;
 			if (n >= 3) {
-				buffer[pos++] = DEC(p[0])<<2 | DEC(p[1])>>4;
-				buffer[pos++] = DEC(p[1])<<4 | DEC(p[2])>>2;
-				buffer[pos++] = DEC(p[2])<<6 | DEC(p[3]);
+				tbuffer[tpos++] = DEC(p[0])<<2 | DEC(p[1])>>4;
+				tbuffer[tpos++] = DEC(p[1])<<4 | DEC(p[2])>>2;
+				tbuffer[tpos++] = DEC(p[2])<<6 | DEC(p[3]);
 			}
 			else {
 				if (n >= 1) {
-					buffer[pos++] =
+					tbuffer[tpos++] =
 						DEC(p[0])<<2 | DEC(p[1])>>4;
 				}
 				if (n >= 2) {
-					buffer[pos++] =
+					tbuffer[tpos++] =
 						DEC(p[1])<<4 | DEC(p[2])>>2;
 				}
 				if (n >= 3) {
-					buffer[pos++] =
+					tbuffer[tpos++] =
 						DEC(p[2])<<6 | DEC(p[3]);
 				}
 			}
+			if (tpos == 0)
+				continue;
+			if (tpos + pos > len) {
+				tpos = len - pos;
+				/*
+				 * Arrange return value > len to indicate
+				 * overflow.
+				 */
+				pos++;
+			}
+			bcopy(tbuffer, bp, tpos);
+			pos += tpos;
+			bp += tpos;
+			if (pos > len)
+				return(pos);
+		}
 	}
 	if (!fgets(temp, sizeof(temp), fd) || strcmp(temp, "end\n"))
 		return(0);
diff --git a/usr.sbin/vidcontrol/decode.h b/usr.sbin/vidcontrol/decode.h
index b939af4..1f1cba4 100644
--- a/usr.sbin/vidcontrol/decode.h
+++ b/usr.sbin/vidcontrol/decode.h
@@ -1 +1,3 @@
-int decode(FILE *fd, char *buffer);
+/* $FreeBSD$ */
+
+int decode(FILE *fd, char *buffer, int len);
diff --git a/usr.sbin/vidcontrol/vidcontrol.1 b/usr.sbin/vidcontrol/vidcontrol.1
index ab92c54..91b6cf3 100644
--- a/usr.sbin/vidcontrol/vidcontrol.1
+++ b/usr.sbin/vidcontrol/vidcontrol.1
@@ -24,7 +24,7 @@
 .Op Fl b Ar color
 .Op Fl c Ar appearance
 .Op Fl d
-.Op Fl f Ar size Ar file
+.Op Fl f Oo Ar size Oc Ar \ file
 .Op Fl g Ar geometry
 .Op Fl i Cm adapter | mode
 .Op Fl l Ar screen_map
@@ -142,7 +142,7 @@ or
 Used together with the 
 .Xr moused 8
 daemon for text mode cut & paste functionality.
-.It Fl f Ar size Ar file
+.It Fl f [ Ar size ] Ar file
 Load font
 .Ar file
 for
@@ -157,6 +157,11 @@ You can also use the menu-driven
 .Xr vidfont 1
 command to load the font of your choice.
 .Pp
+.Ar Size
+may be omitted, in this case
+.Nm
+will try to guess it from the size of font file.
+.Pp
 Note that older video cards, such as MDA and CGA, do not support 
 software font.
 See also
@@ -296,6 +301,11 @@ you may abbreviate the file name as
 .Pp
 .Dl vidcontrol -f 8x16 iso-8x16
 .Pp
+Furthermore, you can also omit font size
+.Dq 8x16 :
+.Pp
+.Dl vidcontrol -f iso-8x16
+.Pp
 Likewise, you can also abbreviate the screen output map file name for
 the
 .Fl l
diff --git a/usr.sbin/vidcontrol/vidcontrol.c b/usr.sbin/vidcontrol/vidcontrol.c
index 42e457b..24ef988 100644
--- a/usr.sbin/vidcontrol/vidcontrol.c
+++ b/usr.sbin/vidcontrol/vidcontrol.c
@@ -41,6 +41,8 @@ static const char rcsid[] =
 #include <sys/fbio.h>
 #include <sys/consio.h>
 #include <sys/errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
 #include "path.h"
 #include "decode.h"
 
@@ -74,12 +76,13 @@ usage()
 }
 
 char *
-nextarg(int ac, char **av, int *indp, int oc)
+nextarg(int ac, char **av, int *indp, int oc, int strict)
 {
 	if (*indp < ac)
 		return(av[(*indp)++]);
-	errx(1, "option requires two arguments -- %c", oc);
-	return("");
+	if (strict != 0)
+		errx(1, "option requires two arguments -- %c", oc);
+	return(NULL);
 }
 
 char *
@@ -129,7 +132,7 @@ load_scrnmap(char *filename)
 		return;
 	}
 	size = sizeof(scrnmap);
-	if (decode(fd, (char *)&scrnmap) != size) {
+	if (decode(fd, (char *)&scrnmap, size) != size) {
 		rewind(fd);
 		if (fread(&scrnmap, 1, size, fd) != size) {
 			warnx("bad screenmap file");
@@ -176,16 +179,38 @@ print_scrnmap()
 
 }
 
+int
+fsize(FILE *file)
+{
+	struct stat sb;
+
+	if (fstat(fileno(file), &sb) == 0)
+		return sb.st_size;
+	else
+		return -1;
+}
+
+#define DATASIZE(x) ((x).w * (x).h * 256 / 8)
+
 void
 load_font(char *type, char *filename)
 {
-	FILE	*fd = 0;
-	int	i, size;
-	unsigned long io;
+	FILE	*fd = NULL;
+	int	h, i, size, w;
+	unsigned long io = 0;	/* silence stupid gcc(1) in the Wall mode */
 	char	*name, *fontmap;
 	char	*prefix[]  = {"", "", FONT_PATH, FONT_PATH, NULL};
 	char	*postfix[] = {"", ".fnt", "", ".fnt"};
 
+	struct sizeinfo {
+		int w;
+		int h;
+		unsigned long io;
+	} sizes[] = {{8, 16, PIO_FONT8x16},
+		     {8, 14, PIO_FONT8x14},
+		     {8,  8,  PIO_FONT8x8},
+		     {0,  0,            0}};
+
 	for (i=0; prefix[i]; i++) {
 		name = mkfullname(prefix[i], filename, postfix[i]);
 		fd = fopen(name, "r");
@@ -193,31 +218,57 @@ load_font(char *type, char *filename)
 			break;
 	}
 	if (fd == NULL) {
-		warn("font file not found");
+		warn("%s: can't load font file", filename);
 		return;
 	}
-	if (!strcmp(type, "8x8")) {
-		size = 8*256;
-		io = PIO_FONT8x8;
-	}
-	else if (!strcmp(type, "8x14")) {
-		size = 14*256;
-		io = PIO_FONT8x14;
-	}
-	else if (!strcmp(type, "8x16")) {
-		size = 16*256;
-		io = PIO_FONT8x16;
-	}
-	else {
-		warn("bad font size specification");
-		fclose(fd);
-		return;
+	if (type != NULL) {
+		size = 0;
+		if (sscanf(type, "%dx%d", &w, &h) == 2)
+			for (i = 0; sizes[i].w != 0; i++)
+				if (sizes[i].w == w && sizes[i].h == h) {
+					size = DATASIZE(sizes[i]);
+					io = sizes[i].io;
+				}
+
+		if (size == 0) {
+			warnx("%s: bad font size specification", type);
+			fclose(fd);
+			return;
+		}
+	} else {
+		/* Apply heuristics */
+		int j;
+		int dsize[2];
+
+		size = DATASIZE(sizes[0]);
+		fontmap = (char*) malloc(size);
+		dsize[0] = decode(fd, fontmap, size);
+		dsize[1] = fsize(fd);
+		free(fontmap);
+
+		size = 0;
+		for (j = 0; j < 2; j++)
+			for (i = 0; sizes[i].w != 0; i++)
+				if (DATASIZE(sizes[i]) == dsize[j]) {
+					size = dsize[j];
+					io = sizes[i].io;
+					j = 2;	/* XXX */
+					break;
+				}
+
+		if (size == 0) {
+			warnx("%s: can't guess font size", filename);
+			fclose(fd);
+			return;
+		}
+		rewind(fd);
 	}
+
 	fontmap = (char*) malloc(size);
-	if (decode(fd, fontmap) != size) {
+	if (decode(fd, fontmap, size) != size) {
 		rewind(fd);
-		if (fread(fontmap, 1, size, fd) != size) {
-			warnx("bad font file");
+		if (fsize(fd) != size || fread(fontmap, 1, size, fd) != size) {
+			warnx("%s: bad font file", filename);
 			fclose(fd);
 			free(fontmap);
 			return;
@@ -590,7 +641,8 @@ test_frame()
 int
 main(int argc, char **argv)
 {
-	int		opt;
+	char	*font, *type;
+	int	opt;
 
 
 	info.size = sizeof(info);
@@ -608,8 +660,13 @@ main(int argc, char **argv)
 				print_scrnmap();
 				break;
 			case 'f':
-				load_font(optarg,
-					nextarg(argc, argv, &optind, 'f'));
+				type = optarg;
+				font = nextarg(argc, argv, &optind, 'f', 0);
+				if (font == NULL) {
+					type = NULL;
+					font = optarg;
+				}
+				load_font(type, font);
 				break;
 			case 'g':
 				if (sscanf(optarg, "%dx%d", &vesa_cols,