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

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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: 1431574a1c (lib/decompressors: fix "no limit" output buffer length)
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Alexandre Courbot <acourbot@nvidia.com>
Cc: Jon Medhurst <tixy@linaro.org>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Yinghai Lu 2015-09-09 15:39:12 -07:00 • committed by Linus Torvalds
parent e852d82a5b
commit 2d3862d26e
14 changed files with 70 additions and 27 deletions
Download patch file Download diff file Expand all files Collapse all files

31
lib/decompress_inflate.c
View file

@ -1,4 +1,5 @@
#ifdef STATIC
#define PREBOOT
/* Pre-boot environment: included */
/* prevent inclusion of _LINUX_KERNEL_H in pre-boot environment: lots
@ -33,23 +34,23 @@ static long INIT nofill(void *buffer, unsigned long len)
}
/* 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");
@ -181,4 +182,24 @@ gunzip_nomem1:
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