MFH: Fix buffer overread in libmagic and sync a skipped change from 4.26

2 files changed, 11 insertions, 9 deletions

diff --git a/ext/fileinfo/libmagic/funcs.c b/ext/fileinfo/libmagic/funcs.c
index 67bd0d5b0e..47ce20c344 100644
--- a/ext/fileinfo/libmagic/funcs.c
+++ b/ext/fileinfo/libmagic/funcs.c
@@ -151,6 +151,7 @@ file_buffer(struct magic_set *ms, php_stream *stream, const char *inname, const
 {
 	int m;
 	int mime = ms->flags & MAGIC_MIME;
+	const unsigned char *ubuf = buf;
 
 	if (nb == 0) {
 		if ((!mime || (mime & MAGIC_MIME_TYPE)) &&
@@ -182,15 +183,15 @@ file_buffer(struct magic_set *ms, php_stream *stream, const char *inname, const
 #if PHP_FILEINFO_UNCOMPRESS
 	/* try compression stuff */
 	if ((ms->flags & MAGIC_NO_CHECK_COMPRESS) != 0 ||
-	    (m = file_zmagic(ms, stream, inname, buf, nb)) == 0) 
+	    (m = file_zmagic(ms, stream, inname, ubuf, nb)) == 0) 
 #endif
 	{
 		/* Check if we have a tar file */
-		if ((ms->flags & MAGIC_NO_CHECK_TAR) != 0 || (m = file_is_tar(ms, buf, nb)) == 0) {
+		if ((ms->flags & MAGIC_NO_CHECK_TAR) != 0 || (m = file_is_tar(ms, ubuf, nb)) == 0) {
 			/* try tests in /etc/magic (or surrogate magic file) */
-			if ((ms->flags & MAGIC_NO_CHECK_SOFT) != 0 || (m = file_softmagic(ms, buf, nb, BINTEST)) == 0) {
+			if ((ms->flags & MAGIC_NO_CHECK_SOFT) != 0 || (m = file_softmagic(ms, ubuf, nb, BINTEST)) == 0) {
 				/* try known keywords, check whether it is ASCII */
-				if ((ms->flags & MAGIC_NO_CHECK_ASCII) != 0 || (m = file_ascmagic(ms, buf, nb)) == 0) {
+				if ((ms->flags & MAGIC_NO_CHECK_ASCII) != 0 || (m = file_ascmagic(ms, ubuf, nb)) == 0) {
 					/* abandon hope, all ye who remain here */
 					if ((!mime || (mime & MAGIC_MIME_TYPE)) && file_printf(ms, mime ? "application/octet-stream" : "data") == -1) {
 						return -1;
@@ -211,7 +212,7 @@ file_buffer(struct magic_set *ms, php_stream *stream, const char *inname, const
 		 * information from the ELF headers that cannot easily
 		 * be extracted with rules in the magic file.
 		 */
-		(void)file_tryelf(ms, stream, buf, nb);
+		(void)file_tryelf(ms, stream, ubuf, nb);
 	}
 #endif
 	return m;
diff --git a/ext/fileinfo/libmagic/softmagic.c b/ext/fileinfo/libmagic/softmagic.c
index 505b2d1128..0eec05c8d2 100644
--- a/ext/fileinfo/libmagic/softmagic.c
+++ b/ext/fileinfo/libmagic/softmagic.c
@@ -185,8 +185,8 @@ match(struct magic_set *ms, struct magic *magic, uint32_t nmagic,
 		if (file_check_mem(ms, ++cont_level) == -1)
 			return -1;
 
-		while (magic[magindex+1].cont_level != 0 &&
-		    ++magindex < nmagic) {
+		while (magindex < nmagic - 1 && magic[magindex + 1].cont_level != 0) {
+			magindex++;
 			m = &magic[magindex];
 			ms->line = m->lineno; /* for messages */
 
@@ -783,6 +783,7 @@ mcopy(struct magic_set *ms, union VALUETYPE *p, int type, int indir,
 			const char *c;
 			const char *last;	/* end of search region */
 			const char *buf;	/* start of search region */
+			const char *end;
 			size_t lines;
 
 			if (s == NULL) {
@@ -791,10 +792,10 @@ mcopy(struct magic_set *ms, union VALUETYPE *p, int type, int indir,
 				return 0;
 			}
 			buf = (const char *)s + offset;
-			last = (const char *)s + nbytes;
+			end = last = (const char *)s + nbytes;
 			/* mget() guarantees buf <= last */
 			for (lines = linecnt, b = buf;
-			     lines && ((b = strchr(c = b, '\n')) || (b = strchr(c, '\r')));
+			     lines && ((b = memchr(c = b, '\n', end - b)) || (b = memchr(c, '\r', end - c)));
 			     lines--, b++) {
 				last = b;
 				if (b[0] == '\r' && b[1] == '\n')