X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=archival%2Flibunarchive%2Fdecompress_unzip.c;h=3a7334ce9e10760bfd26a1609680a312f40785cc;hb=826b48b624e3c02b432b8ffbb7809657ddb3a012;hp=d8d5b77b1f4281c18f5afafe6a97b4b1d0852e77;hpb=83bf47c02f95a9956eb4f6a185014ab0fb62670b;p=oweals%2Fbusybox.git

diff --git a/archival/libunarchive/decompress_unzip.c b/archival/libunarchive/decompress_unzip.c
index d8d5b77b1..3a7334ce9 100644
--- a/archival/libunarchive/decompress_unzip.c
+++ b/archival/libunarchive/decompress_unzip.c
@@ -86,16 +86,11 @@ static int gunzip_src_fd;
 unsigned int gunzip_bytes_out;	/* number of output bytes */
 static unsigned int gunzip_outbuf_count;	/* bytes in output buffer */
 
-/* This is used to sanify any unused bits from the bitbuffer 
- * so they arent skipped when reading trailers (trailing headers) */
-unsigned char gunzip_in_buffer_count;
-unsigned char *gunzip_in_buffer;
-
 /* gunzip_window size--must be a power of two, and
  *  at least 32K for zip's deflate method */
 static const int gunzip_wsize = 0x8000;
-
 static unsigned char *gunzip_window;
+
 static unsigned int *gunzip_crc_table;
 unsigned int gunzip_crc;
 
@@ -103,9 +98,16 @@ unsigned int gunzip_crc;
 #define BMAX 16	/* maximum bit length of any code (16 for explode) */
 #define N_MAX 288	/* maximum number of codes in any set */
 
+/* bitbuffer */
 static unsigned int gunzip_bb;	/* bit buffer */
 static unsigned char gunzip_bk;	/* bits in bit buffer */
 
+/* These control the size of the bytebuffer */
+#define BYTEBUFFER_MAX 0x8000
+static unsigned char *bytebuffer = NULL;
+static unsigned int bytebuffer_offset = 0;
+static unsigned int bytebuffer_size = 0;
+
 static const unsigned short mask_bits[] = {
 	0x0000, 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
 	0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
@@ -142,13 +144,25 @@ static const unsigned char border[] = {
 	16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
 };
 
+static void fill_bytebuffer(void)
+{
+	if (bytebuffer_offset >= bytebuffer_size) {
+		/* Leave the first 4 bytes empty so we can always unwind the bitbuffer 
+		 * to the front of the bytebuffer, leave 4 bytes free at end of tail
+		 * so we can easily top up buffer in check_trailer_gzip() */
+		bytebuffer_size = 4 + xread(gunzip_src_fd, &bytebuffer[4], BYTEBUFFER_MAX - 8);
+		bytebuffer_offset = 4;
+	}
+}
+
 static unsigned int fill_bitbuffer(unsigned int bitbuffer, unsigned int *current, const unsigned int required)
 {
 	while (*current < required) {
-		bitbuffer |= ((unsigned int) xread_char(gunzip_src_fd)) << *current;
+		fill_bytebuffer();
+		bitbuffer |= ((unsigned int) bytebuffer[bytebuffer_offset]) << *current;
+		bytebuffer_offset++;
 		*current += 8;
 	}
-
 	return(bitbuffer);
 }
 
@@ -857,7 +871,10 @@ static int inflate_get_next_window(void)
 		int ret;
 	
 		if (needAnotherBlock) {
-			if(e) { calculate_gunzip_crc(); return 0; } // Last block
+			if(e) {
+				calculate_gunzip_crc();
+				return 0;
+			} // Last block
 			method = inflate_block(&e);
 			needAnotherBlock = 0;
 		}
@@ -875,6 +892,7 @@ static int inflate_get_next_window(void)
 			return 1; // More data left
 		} else needAnotherBlock = 1; // End of that block
 	}
+	/* Doesnt get here */
 }
 
 /*
@@ -923,7 +941,8 @@ extern void GZ_gzReadOpen(int fd, void *unused, int nUnused)
 	gunzip_bytes_out = 0;
 	gunzip_src_fd = fd;
 
-	gunzip_in_buffer = malloc(8);
+	/* Input buffer */
+	bytebuffer = xmalloc(BYTEBUFFER_MAX);
 
 	/* initialize gunzip_window, bit buffer */
 	gunzip_bk = 0;
@@ -940,12 +959,11 @@ extern void GZ_gzReadClose(void)
 	free(gunzip_crc_table);
 
 	/* Store unused bytes in a global buffer so calling applets can access it */
-	gunzip_in_buffer_count = 0;
 	if (gunzip_bk >= 8) {
 		/* Undo too much lookahead. The next read will be byte aligned
 		 * so we can discard unused bits in the last meaningful byte. */
-		gunzip_in_buffer[gunzip_in_buffer_count] = gunzip_bb & 0xff;
-		gunzip_in_buffer_count++;
+		bytebuffer_offset--;
+		bytebuffer[bytebuffer_offset] = gunzip_bb & 0xff;
 		gunzip_bb >>= 8;
 		gunzip_bk -= 8;
 	}
@@ -990,3 +1008,33 @@ extern int inflate(int in, int out)
 	GZ_gzReadClose();
 	return 0;
 }
+
+extern void check_trailer_gzip(int src_fd)
+{
+	unsigned int stored_crc = 0;
+	unsigned char count;
+
+	/* top up the input buffer with the rest of the trailer */
+	count = bytebuffer_size - bytebuffer_offset;
+	if (count < 8) {
+		xread_all(src_fd, &bytebuffer[bytebuffer_size], 8 - count);
+		bytebuffer_size += 8 - count;
+	}
+	for (count = 0; count != 4; count++) {
+		stored_crc |= (bytebuffer[bytebuffer_offset] << (count * 8));
+		bytebuffer_offset++;
+	}
+
+	/* Validate decompression - crc */
+	if (stored_crc != (gunzip_crc ^ 0xffffffffL)) {
+		error_msg_and_die("crc error");
+	}
+
+	/* Validate decompression - size */
+	if (gunzip_bytes_out !=
+		(bytebuffer[bytebuffer_offset] | (bytebuffer[bytebuffer_offset+1] << 8) |
+		(bytebuffer[bytebuffer_offset+2] << 16) | (bytebuffer[bytebuffer_offset+3] << 24))) {
+		error_msg_and_die("Incorrect length, but crc is correct");
+	}
+
+}