提交 a46393ab 编写于 作者: J Jacob von Chorus 提交者: Greg Kroah-Hartman

staging: gs_fpgaboot: add buffer overflow checks

Four fields in struct fpgaimage are char arrays of length MAX_STR (256).
The amount of data read into these buffers is controlled by a length
field in the bitstream file read from userspace. If a corrupt or
malicious firmware file was supplied, kernel data beyond these buffers
can be overwritten arbitrarily.

This patch adds a check of the bitstream's length value to ensure it
fits within the bounds of the allocated buffers. An error condition is
returned from gs_read_bitstream if any of the reads fail.
Signed-off-by: NJacob von Chorus <jacobvonchorus@cwphoto.ca>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
上级 ee714b80
......@@ -23,6 +23,7 @@
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/firmware.h>
#include <asm/unaligned.h>
#include "gs_fpgaboot.h"
#include "io.h"
......@@ -47,7 +48,7 @@ static void read_bitstream(char *bitdata, char *buf, int *offset, int rdsize)
*offset += rdsize;
}
static void readinfo_bitstream(char *bitdata, char *buf, int *offset)
static int readinfo_bitstream(char *bitdata, char *buf, int size, int *offset)
{
char tbuf[64];
s32 len;
......@@ -58,10 +59,16 @@ static void readinfo_bitstream(char *bitdata, char *buf, int *offset)
/* read length */
read_bitstream(bitdata, tbuf, offset, 2);
len = tbuf[0] << 8 | tbuf[1];
len = get_unaligned_be16(tbuf);
if (len >= size) {
pr_err("error: readinfo buffer too small\n");
return -EINVAL;
}
read_bitstream(bitdata, buf, offset, len);
buf[len] = '\0';
return 0;
}
/*
......@@ -83,8 +90,7 @@ static int readlength_bitstream(char *bitdata, int *lendata, int *offset)
/* read 4bytes length */
read_bitstream(bitdata, tbuf, offset, 4);
*lendata = tbuf[0] << 24 | tbuf[1] << 16 |
tbuf[2] << 8 | tbuf[3];
*lendata = get_unaligned_be32(tbuf);
return 0;
}
......@@ -113,7 +119,7 @@ static int readmagic_bitstream(char *bitdata, int *offset)
/*
* NOTE: supports only bitstream format
*/
static enum fmt_image get_imageformat(struct fpgaimage *fimage)
static enum fmt_image get_imageformat(void)
{
return f_bit;
}
......@@ -127,34 +133,54 @@ static void gs_print_header(struct fpgaimage *fimage)
pr_info("lendata: %d\n", fimage->lendata);
}
static void gs_read_bitstream(struct fpgaimage *fimage)
static int gs_read_bitstream(struct fpgaimage *fimage)
{
char *bitdata;
int offset;
int err;
offset = 0;
bitdata = (char *)fimage->fw_entry->data;
readmagic_bitstream(bitdata, &offset);
readinfo_bitstream(bitdata, fimage->filename, &offset);
readinfo_bitstream(bitdata, fimage->part, &offset);
readinfo_bitstream(bitdata, fimage->date, &offset);
readinfo_bitstream(bitdata, fimage->time, &offset);
readlength_bitstream(bitdata, &fimage->lendata, &offset);
err = readmagic_bitstream(bitdata, &offset);
if (err)
return err;
err = readinfo_bitstream(bitdata, fimage->filename, MAX_STR, &offset);
if (err)
return err;
err = readinfo_bitstream(bitdata, fimage->part, MAX_STR, &offset);
if (err)
return err;
err = readinfo_bitstream(bitdata, fimage->date, MAX_STR, &offset);
if (err)
return err;
err = readinfo_bitstream(bitdata, fimage->time, MAX_STR, &offset);
if (err)
return err;
err = readlength_bitstream(bitdata, &fimage->lendata, &offset);
if (err)
return err;
fimage->fpgadata = bitdata + offset;
return 0;
}
static int gs_read_image(struct fpgaimage *fimage)
{
int img_fmt;
int err;
img_fmt = get_imageformat(fimage);
img_fmt = get_imageformat();
switch (img_fmt) {
case f_bit:
pr_info("image is bitstream format\n");
gs_read_bitstream(fimage);
err = gs_read_bitstream(fimage);
if (err)
return err;
break;
default:
pr_err("unsupported fpga image format\n");
......
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