add 7z SFX support - bb#3063

ChangeLog

@@ -1,3 +1,7 @@
+Tue Nov  1 12:26:46 CET 2011 (acab)
+-----------------------------------
+ * libclamav: Add 7z SFX support (b#3063)
+
 Thu Jun  9 08:22:31 CEST 2011 (acab)
 ------------------------------------
  * libclamav/mew.c: harden boundary check on e8/e9 fixup

libclamav/7z_iface.c

@@ -71,13 +71,14 @@ static SRes FileInStream_fmap_Seek(void *pp, Int64 *pos, ESzSeek origin) {
 }
 
 #define UTFBUFSZ 256
-int cli_7unz (cli_ctx *ctx) {
+int cli_7unz (cli_ctx *ctx, size_t offset) {
     CFileInStream archiveStream;
     CLookToRead lookStream;
     CSzArEx db;
     SRes res;
     UInt16 utf16buf[UTFBUFSZ], *utf16name = utf16buf;
     int namelen = UTFBUFSZ, found = CL_CLEAN;
+    Int64 begin_of_archive = offset;
 
     /* Replacement for 
        FileInStream_CreateVTable(&archiveStream); */
@@ -88,6 +89,9 @@ int cli_7unz (cli_ctx *ctx) {
 
     LookToRead_CreateVTable(&lookStream, False);
   
+    if(archiveStream.s.Seek(&archiveStream.s, &begin_of_archive, SZ_SEEK_SET) != 0)
+	return CL_CLEAN;
+
     lookStream.realStream = &archiveStream.s;
     LookToRead_Init(&lookStream);
 

libclamav/7z_iface.h

@@ -27,6 +27,6 @@
 
 #include "others.h"
 
-int cli_7unz (cli_ctx *);
+int cli_7unz (cli_ctx *, size_t);
 
 #endif

libclamav/filetypes.c

@@ -96,6 +96,7 @@ static const struct ftmap_s {
     { "CL_TYPE_AUTOIT",		CL_TYPE_AUTOIT		},
     { "CL_TYPE_ISHIELD_MSI",	CL_TYPE_ISHIELD_MSI	},
     { "CL_TYPE_7Z",		CL_TYPE_7Z		},
+    { "CL_TYPE_7ZSFX",		CL_TYPE_7ZSFX		},
     { "CL_TYPE_SWF",		CL_TYPE_SWF		},
     { NULL,			CL_TYPE_IGNORED		}
 };

libclamav/filetypes.h

@@ -80,6 +80,7 @@ typedef enum {
     CL_TYPE_SFX, /* foo SFX marker */
     CL_TYPE_ZIPSFX, /* on the fly */
     CL_TYPE_RARSFX, /* on the fly */
+    CL_TYPE_7ZSFX,
     CL_TYPE_CABSFX,
     CL_TYPE_ARJSFX,
     CL_TYPE_NULSFT, /* on the fly */

libclamav/filetypes_int.h

@@ -155,6 +155,7 @@ static const char *ftypes_int[] = {
   "0:0:435753:SWF (compressed):CL_TYPE_ANY:CL_TYPE_SWF:62",
   "0:0:465753:SWF (uncompressed):CL_TYPE_ANY:CL_TYPE_SWF:62",
   "0:0:ffd9ffd8:JPEG (bad header):CL_TYPE_ANY:CL_TYPE_GRAPHICS:62",
+  "1:*:377abcaf271c:7zip-SFX:CL_TYPE_ANY:CL_TYPE_7ZSFX",
   NULL
 };
 

libclamav/scanners.c

@@ -1902,6 +1902,15 @@ static int cli_scanraw(cli_ctx *ctx, cli_file_t type, uint8_t typercg, cli_file_
 			}
 			break;
 
+		    case CL_TYPE_7ZSFX:
+			if(type != CL_TYPE_7Z && SCAN_ARCHIVE && (DCONF_ARCH & ARCH_CONF_7Z)) {
+			    ctx->container_type = CL_TYPE_7Z;
+			    ctx->container_size = map->len - fpt->offset; /* not precise */
+			    cli_dbgmsg("7Zip-SFX signature found at %u\n", (unsigned int) fpt->offset);
+			    nret = cli_7unz(ctx, fpt->offset);
+			}
+			break;
+
 		    case CL_TYPE_NULSFT:
 		        if(SCAN_ARCHIVE && type == CL_TYPE_MSEXE && (DCONF_ARCH & ARCH_CONF_NSIS) && fpt->offset > 4) {
 			    ctx->container_type = CL_TYPE_NULSFT;
@@ -2307,7 +2316,7 @@ static int magic_scandesc(cli_ctx *ctx, cli_file_t type)
 	case CL_TYPE_7Z:
 	    ctx->container_type = CL_TYPE_7Z;
 	    if(SCAN_ARCHIVE && (DCONF_ARCH & ARCH_CONF_7Z))
-		ret = cli_7unz(ctx);
+		ret = cli_7unz(ctx, 0);
 	    break;
 
 	case CL_TYPE_POSIX_TAR: