lib/decompressors: use real out buf size for gunzip with kernel

When loading x86 64bit kernel above 4GiB with patched grub2, got kernel
gunzip error.

| early console in decompress_kernel
| decompress_kernel:
| input: [0x807f2143b4-0x807ff61aee]
| output: [0x807cc00000-0x807f3ea29b] 0x027ea29c: output_len
| boot via startup_64
| KASLR using RDTSC...
| new output: [0x46fe000000-0x470138cfff] 0x0338d000: output_run_size
| decompress: [0x46fe000000-0x47007ea29b] <=== [0x807f2143b4-0x807ff61aee]
|
| Decompressing Linux... gz...
|
| uncompression error
|
| -- System halted

the new buffer is at 0x46fe000000ULL, decompressor_gzip is using
0xffffffb901ffffff as out_len. gunzip in lib/zlib_inflate/inflate.c cap
that len to 0x01ffffff and decompress fails later.

We could hit this problem with crashkernel booting that uses kexec loading
kernel above 4GiB.

We have decompress_* support:
1. inbuf[]/outbuf[] for kernel preboot.
2. inbuf[]/flush() for initramfs
3. fill()/flush() for initrd.
This bug only affect kernel preboot path that use outbuf[].

Add __decompress and take real out_buf_len for gunzip instead of guessing
wrong buf size.

Fixes: 1431574a1c4 (lib/decompressors: fix "no limit" output buffer length)
Signed-off-by: Yinghai Lu <[e-mail]>
Cc: Alexandre Courbot <[e-mail]>
Cc: Jon Medhurst <[e-mail]>
Cc: Stephen Warren <[e-mail]>
Cc: "H. Peter Anvin" <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/arm/boot/compressed/decompress.c

···
 
 int do_decompress(u8 *input, int len, u8 *output, void (*error)(char *x))
 {
-	return decompress(input, len, NULL, NULL, output, NULL, error);
+	return __decompress(input, len, NULL, NULL, output, 0, NULL, error);
 }

arch/h8300/boot/compressed/misc.c

···
 	free_mem_ptr = (unsigned long)&_end;
 	free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
 
-	decompress(input_data, input_len, NULL, NULL, output, NULL, error);
+	__decompress(input_data, input_len, NULL, NULL, output, 0, NULL, error);
 }

arch/m32r/boot/compressed/misc.c

···
 	free_mem_end_ptr = free_mem_ptr + BOOT_HEAP_SIZE;
 
 	puts("\nDecompressing Linux... ");
-	decompress(input_data, input_len, NULL, NULL, output_data, NULL, error);
+	__decompress(input_data, input_len, NULL, NULL, output_data, 0,
+			NULL, error);
 	puts("done.\nBooting the kernel.\n");
 }

arch/mips/boot/compressed/decompress.c

···
 	puts("\n");
 
 	/* Decompress the kernel with according algorithm */
-	decompress((char *)zimage_start, zimage_size, 0, 0,
-		   (void *)VMLINUX_LOAD_ADDRESS_ULL, 0, error);
+	__decompress((char *)zimage_start, zimage_size, 0, 0,
+		   (void *)VMLINUX_LOAD_ADDRESS_ULL, 0, 0, error);
 
 	/* FIXME: should we flush cache here? */
 	puts("Now, booting the kernel...\n");

arch/s390/boot/compressed/misc.c

···
 #endif
 
 	puts("Uncompressing Linux... ");
-	decompress(input_data, input_len, NULL, NULL, output, NULL, error);
+	__decompress(input_data, input_len, NULL, NULL, output, 0, NULL, error);
 	puts("Ok, booting the kernel.\n");
 	return (unsigned long) output;
 }

arch/sh/boot/compressed/misc.c

···
 
 	puts("Uncompressing Linux... ");
 	cache_control(CACHE_ENABLE);
-	decompress(input_data, input_len, NULL, NULL, output, NULL, error);
+	__decompress(input_data, input_len, NULL, NULL, output, 0, NULL, error);
 	cache_control(CACHE_DISABLE);
 	puts("Ok, booting the kernel.\n");
 }

arch/unicore32/boot/compressed/misc.c

···
 	output_ptr = get_unaligned_le32(tmp);
 
 	arch_decomp_puts("Uncompressing Linux...");
-	decompress(input_data, input_data_end - input_data, NULL, NULL,
-			output_data, NULL, error);
+	__decompress(input_data, input_data_end - input_data, NULL, NULL,
+			output_data, 0, NULL, error);
 	arch_decomp_puts(" done, booting the kernel.\n");
 	return output_ptr;
 }

arch/x86/boot/compressed/misc.c

···
 #endif
 
 	debug_putstr("\nDecompressing Linux... ");
-	decompress(input_data, input_len, NULL, NULL, output, NULL, error);
+	__decompress(input_data, input_len, NULL, NULL, output, output_len,
+			NULL, error);
 	parse_elf(output);
 	/*
 	 * 32-bit always performs relocations. 64-bit relocations are only

lib/decompress_bunzip2.c

···
 }
 
 #ifdef PREBOOT
-STATIC int INIT decompress(unsigned char *buf, long len,
+STATIC int INIT __decompress(unsigned char *buf, long len,
 			long (*fill)(void*, unsigned long),
 			long (*flush)(void*, unsigned long),
-			unsigned char *outbuf,
+			unsigned char *outbuf, long olen,
 			long *pos,
-			void(*error)(char *x))
+			void (*error)(char *x))
 {
 	return bunzip2(buf, len - 4, fill, flush, outbuf, pos, error);
 }

lib/decompress_inflate.c

···
 #ifdef STATIC
+#define PREBOOT
 /* Pre-boot environment: included */
 
 /* prevent inclusion of _LINUX_KERNEL_H in pre-boot environment: lots
···
 }
 
 /* Included from initramfs et al code */
-STATIC int INIT gunzip(unsigned char *buf, long len,
+STATIC int INIT __gunzip(unsigned char *buf, long len,
 		       long (*fill)(void*, unsigned long),
 		       long (*flush)(void*, unsigned long),
-		       unsigned char *out_buf,
+		       unsigned char *out_buf, long out_len,
 		       long *pos,
 		       void(*error)(char *x)) {
 	u8 *zbuf;
 	struct z_stream_s *strm;
 	int rc;
-	size_t out_len;
 
 	rc = -1;
 	if (flush) {
 		out_len = 0x8000; /* 32 K */
 		out_buf = malloc(out_len);
 	} else {
-		out_len = ((size_t)~0) - (size_t)out_buf; /* no limit */
+		if (!out_len)
+			out_len = ((size_t)~0) - (size_t)out_buf; /* no limit */
 	}
 	if (!out_buf) {
 		error("Out of memory while allocating output buffer");
···
 	return rc; /* returns Z_OK (0) if successful */
 }
 
-#define decompress gunzip
+#ifndef PREBOOT
+STATIC int INIT gunzip(unsigned char *buf, long len,
+		       long (*fill)(void*, unsigned long),
+		       long (*flush)(void*, unsigned long),
+		       unsigned char *out_buf,
+		       long *pos,
+		       void (*error)(char *x))
+{
+	return __gunzip(buf, len, fill, flush, out_buf, 0, pos, error);
+}
+#else
+STATIC int INIT __decompress(unsigned char *buf, long len,
+			   long (*fill)(void*, unsigned long),
+			   long (*flush)(void*, unsigned long),
+			   unsigned char *out_buf, long out_len,
+			   long *pos,
+			   void (*error)(char *x))
+{
+	return __gunzip(buf, len, fill, flush, out_buf, out_len, pos, error);
+}
+#endif

lib/decompress_unlz4.c

···
 }
 
 #ifdef PREBOOT
-STATIC int INIT decompress(unsigned char *buf, long in_len,
+STATIC int INIT __decompress(unsigned char *buf, long in_len,
 			      long (*fill)(void*, unsigned long),
 			      long (*flush)(void*, unsigned long),
-			      unsigned char *output,
+			      unsigned char *output, long out_len,
 			      long *posp,
-			      void(*error)(char *x)
+			      void (*error)(char *x)
 	)
 {
 	return unlz4(buf, in_len - 4, fill, flush, output, posp, error);

lib/decompress_unlzma.c

···
 }
 
 #ifdef PREBOOT
-STATIC int INIT decompress(unsigned char *buf, long in_len,
+STATIC int INIT __decompress(unsigned char *buf, long in_len,
 			      long (*fill)(void*, unsigned long),
 			      long (*flush)(void*, unsigned long),
-			      unsigned char *output,
+			      unsigned char *output, long out_len,
 			      long *posp,
-			      void(*error)(char *x)
-	)
+			      void (*error)(char *x))
 {
 	return unlzma(buf, in_len - 4, fill, flush, output, posp, error);
 }

lib/decompress_unlzo.c

···
  */
 
 #ifdef STATIC
+#define PREBOOT
 #include "lzo/lzo1x_decompress_safe.c"
 #else
 #include <linux/decompress/unlzo.h>
···
 	return ret;
 }
 
-#define decompress unlzo
+#ifdef PREBOOT
+STATIC int INIT __decompress(unsigned char *buf, long len,
+			   long (*fill)(void*, unsigned long),
+			   long (*flush)(void*, unsigned long),
+			   unsigned char *out_buf, long olen,
+			   long *pos,
+			   void (*error)(char *x))
+{
+	return unlzo(buf, len, fill, flush, out_buf, pos, error);
+}
+#endif

lib/decompress_unxz.c

···
  * This macro is used by architecture-specific files to decompress
  * the kernel image.
  */
-#define decompress unxz
+#ifdef XZ_PREBOOT
+STATIC int INIT __decompress(unsigned char *buf, long len,
+			   long (*fill)(void*, unsigned long),
+			   long (*flush)(void*, unsigned long),
+			   unsigned char *out_buf, long olen,
+			   long *pos,
+			   void (*error)(char *x))
+{
+	return unxz(buf, len, fill, flush, out_buf, pos, error);
+}
+#endif