Commit 6a881162 authored by Phillip Lougher's avatar Phillip Lougher Committed by Linus Torvalds

lzma/gzip: fix potential oops when input data is truncated

If the lzma/gzip decompressors are called with insufficient input data
(len > 0 & fill = NULL), they will attempt to call the fill function to
obtain more data, leading to a kernel oops.
Signed-off-by: default avatarPhillip Lougher <phillip@lougher.demon.co.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3354f73b
......@@ -27,6 +27,11 @@
#define GZIP_IOBUF_SIZE (16*1024)
static int nofill(void *buffer, unsigned int len)
{
return -1;
}
/* Included from initramfs et al code */
STATIC int INIT gunzip(unsigned char *buf, int len,
int(*fill)(void*, unsigned int),
......@@ -76,6 +81,9 @@ STATIC int INIT gunzip(unsigned char *buf, int len,
goto gunzip_nomem4;
}
if (!fill)
fill = nofill;
if (len == 0)
len = fill(zbuf, GZIP_IOBUF_SIZE);
......
......@@ -82,6 +82,11 @@ struct rc {
#define RC_MODEL_TOTAL_BITS 11
static int nofill(void *buffer, unsigned int len)
{
return -1;
}
/* Called twice: once at startup and once in rc_normalize() */
static void INIT rc_read(struct rc *rc)
{
......@@ -97,7 +102,10 @@ static inline void INIT rc_init(struct rc *rc,
int (*fill)(void*, unsigned int),
char *buffer, int buffer_size)
{
rc->fill = fill;
if (fill)
rc->fill = fill;
else
rc->fill = nofill;
rc->buffer = (uint8_t *)buffer;
rc->buffer_size = buffer_size;
rc->buffer_end = rc->buffer + rc->buffer_size;
......
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