Upstream-Author: Christos Zoulas <christos@zoulas.com>
Date: Wed Jan 8 22:22:54 2014 +0000
Last-Update: 2014-03-05
Upstream-Commit:
    447558595a3650db2886cd2f416ad0beba965801
    70c65d2e1841491f59168db1f905e8b14083fb1c
Description:
 PR/313: Aaron Reffett: Check properly for exceeding the offset.
 .
 off by one in out of bounds calculations (Jan Kaluza)
 .
 CVE-2014-2270
 Backport for 5.11: Christoph Biedl <debian.axhn@manchmal.in-ulm.de>

--- a/src/softmagic.c
+++ b/src/softmagic.c
@@ -60,6 +60,7 @@
 private void cvt_32(union VALUETYPE *, const struct magic *);
 private void cvt_64(union VALUETYPE *, const struct magic *);
 
+#define OFFSET_OOB(n, o, i)	((n) < (o) || (i) > ((n) - (o)))
 /*
  * softmagic - lookup one file in parsed, in-memory copy of database
  * Passed the name and FILE * of one file to be typed.
@@ -1080,7 +1081,7 @@
 		}
 		switch (m->in_type) {
 		case FILE_BYTE:
-			if (nbytes < (offset + 1))
+			if (OFFSET_OOB(nbytes, offset, 1))
 				return 0;
 			if (off) {
 				switch (m->in_op & FILE_OPS_MASK) {
@@ -1115,7 +1116,7 @@
 				offset = ~offset;
 			break;
 		case FILE_BESHORT:
-			if (nbytes < (offset + 2))
+			if (OFFSET_OOB(nbytes, offset, 2))
 				return 0;
 			if (off) {
 				switch (m->in_op & FILE_OPS_MASK) {
@@ -1167,7 +1168,7 @@
 				offset = ~offset;
 			break;
 		case FILE_LESHORT:
-			if (nbytes < (offset + 2))
+			if (OFFSET_OOB(nbytes, offset, 2))
 				return 0;
 			if (off) {
 				switch (m->in_op & FILE_OPS_MASK) {
@@ -1219,7 +1220,7 @@
 				offset = ~offset;
 			break;
 		case FILE_SHORT:
-			if (nbytes < (offset + 2))
+			if (OFFSET_OOB(nbytes, offset, 2))
 				return 0;
 			if (off) {
 				switch (m->in_op & FILE_OPS_MASK) {
@@ -1256,7 +1257,7 @@
 			break;
 		case FILE_BELONG:
 		case FILE_BEID3:
-			if (nbytes < (offset + 4))
+			if (OFFSET_OOB(nbytes, offset, 4))
 				return 0;
 			if (off) {
 				switch (m->in_op & FILE_OPS_MASK) {
@@ -1327,7 +1328,7 @@
 			break;
 		case FILE_LELONG:
 		case FILE_LEID3:
-			if (nbytes < (offset + 4))
+			if (OFFSET_OOB(nbytes, offset, 4))
 				return 0;
 			if (off) {
 				switch (m->in_op & FILE_OPS_MASK) {
@@ -1397,7 +1398,7 @@
 				offset = ~offset;
 			break;
 		case FILE_MELONG:
-			if (nbytes < (offset + 4))
+			if (OFFSET_OOB(nbytes, offset, 4))
 				return 0;
 			if (off) {
 				switch (m->in_op & FILE_OPS_MASK) {
@@ -1467,7 +1468,7 @@
 				offset = ~offset;
 			break;
 		case FILE_LONG:
-			if (nbytes < (offset + 4))
+			if (OFFSET_OOB(nbytes, offset, 4))
 				return 0;
 			if (off) {
 				switch (m->in_op & FILE_OPS_MASK) {
@@ -1534,14 +1535,14 @@
 	/* Verify we have enough data to match magic type */
 	switch (m->type) {
 	case FILE_BYTE:
-		if (nbytes < (offset + 1)) /* should alway be true */
+		if (OFFSET_OOB(nbytes, offset, 1))
 			return 0;
 		break;
 
 	case FILE_SHORT:
 	case FILE_BESHORT:
 	case FILE_LESHORT:
-		if (nbytes < (offset + 2))
+		if (OFFSET_OOB(nbytes, offset, 2))
 			return 0;
 		break;
 
@@ -1560,26 +1561,26 @@
 	case FILE_FLOAT:
 	case FILE_BEFLOAT:
 	case FILE_LEFLOAT:
-		if (nbytes < (offset + 4))
+		if (OFFSET_OOB(nbytes, offset, 4))
 			return 0;
 		break;
 
 	case FILE_DOUBLE:
 	case FILE_BEDOUBLE:
 	case FILE_LEDOUBLE:
-		if (nbytes < (offset + 8))
+		if (OFFSET_OOB(nbytes, offset, 8))
 			return 0;
 		break;
 
 	case FILE_STRING:
 	case FILE_PSTRING:
 	case FILE_SEARCH:
-		if (nbytes < (offset + m->vallen))
+		if (OFFSET_OOB(nbytes, offset, m->vallen))
 			return 0;
 		break;
 
 	case FILE_REGEX:
-		if (nbytes < offset)
+		if (OFFSET_OOB(nbytes, offset, 0))
 			return 0;
 		break;
 
@@ -1589,7 +1590,7 @@
 	  	if ((ms->flags & (MAGIC_MIME|MAGIC_APPLE)) == 0 &&
 		    file_printf(ms, "%s", m->desc) == -1)
 			return -1;
-		if (nbytes < offset)
+		if (OFFSET_OOB(nbytes, offset, 0))
 			return 0;
 		return file_softmagic(ms, s + offset, nbytes - offset,
 		    recursion_level, BINTEST, text);