Adding upstream version 2:2.1.0.upstream/2%2.1.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 282 insertions, 0 deletions

diff --git a/lib/verity/verity_fec.c b/lib/verity/verity_fec.c
new file mode 100644
index 0000000..735e923
--- /dev/null
+++ b/lib/verity/verity_fec.c
@@ -0,0 +1,282 @@
+/*
+ * dm-verity Forward Error Correction (FEC) support
+ *
+ * Copyright (C) 2015 Google, Inc. All rights reserved.
+ * Copyright (C) 2017-2019 Red Hat, Inc. All rights reserved.
+ *
+ * This file is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This file is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this file; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <stdlib.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include "verity.h"
+#include "internal.h"
+#include "rs.h"
+
+/* ecc parameters */
+#define FEC_RSM 255
+#define FEC_MIN_RSN 231
+#define FEC_MAX_RSN 253
+
+#define FEC_INPUT_DEVICES 2
+
+/* parameters to init_rs_char */
+#define FEC_PARAMS(roots) \
+    8,          /* symbol size in bits */ \
+    0x11d,      /* field generator polynomial coefficients */ \
+    0,          /* first root of the generator */ \
+    1,          /* primitive element to generate polynomial roots */ \
+    (roots),    /* polynomial degree (number of roots) */ \
+    0           /* padding bytes at the front of shortened block */
+
+struct fec_input_device {
+	struct device *device;
+	int fd;
+	uint64_t start;
+	uint64_t count;
+};
+
+struct fec_context {
+	uint32_t rsn;
+	uint32_t roots;
+	uint64_t size;
+	uint64_t blocks;
+	uint64_t rounds;
+	uint32_t block_size;
+	struct fec_input_device *inputs;
+	size_t ninputs;
+};
+
+/* computes ceil(x / y) */
+static inline uint64_t FEC_div_round_up(uint64_t x, uint64_t y)
+{
+	return (x / y) + (x % y > 0 ? 1 : 0);
+}
+
+/* returns a physical offset for the given RS offset */
+static inline uint64_t FEC_interleave(struct fec_context *ctx, uint64_t offset)
+{
+	return (offset / ctx->rsn) +
+			(offset % ctx->rsn) * ctx->rounds * ctx->block_size;
+}
+
+/* returns data for a byte at the specified RS offset */
+static int FEC_read_interleaved(struct fec_context *ctx, uint64_t i,
+				void *output, size_t count)
+{
+	size_t n;
+	uint64_t offset = FEC_interleave(ctx, i);
+
+	/* offsets outside input area are assumed to contain zeros */
+	if (offset >= ctx->size) {
+		memset(output, 0, count);
+		return 0;
+	}
+
+	/* find the correct input device and read from it */
+	for (n = 0; n < ctx->ninputs; ++n) {
+		if (offset >= ctx->inputs[n].count) {
+			offset -= ctx->inputs[n].count;
+			continue;
+		}
+
+		/* FIXME: read_lseek_blockwise candidate */
+		if (lseek(ctx->inputs[n].fd, ctx->inputs[n].start + offset, SEEK_SET) < 0)
+			return -1;
+		return (read_buffer(ctx->inputs[n].fd, output, count) == (ssize_t)count) ? 0 : -1;
+	}
+
+	/* should never be reached */
+	return -1;
+}
+
+/* encodes/decode inputs to/from fd */
+static int FEC_process_inputs(struct crypt_device *cd,
+			      struct crypt_params_verity *params,
+			      struct fec_input_device *inputs,
+			      size_t ninputs, int fd,
+			      int decode, unsigned int *errors)
+{
+	int r = 0;
+	unsigned int i;
+	struct fec_context ctx;
+	uint32_t b;
+	uint64_t n;
+	uint8_t rs_block[FEC_RSM];
+	uint8_t *buf = NULL;
+	void *rs;
+
+	/* initialize parameters */
+	ctx.roots = params->fec_roots;
+	ctx.rsn = FEC_RSM - ctx.roots;
+	ctx.block_size = params->data_block_size;
+	ctx.inputs = inputs;
+	ctx.ninputs = ninputs;
+
+	rs = init_rs_char(FEC_PARAMS(ctx.roots));
+	if (!rs) {
+		log_err(cd, _("Failed to allocate RS context."));
+		return -ENOMEM;
+	}
+
+	/* calculate the total area covered by error correction codes */
+	ctx.size = 0;
+	for (n = 0; n < ctx.ninputs; ++n)
+		ctx.size += ctx.inputs[n].count;
+
+	/* each byte in a data block is covered by a different code */
+	ctx.blocks = FEC_div_round_up(ctx.size, ctx.block_size);
+	ctx.rounds = FEC_div_round_up(ctx.blocks, ctx.rsn);
+
+	buf = malloc((size_t)ctx.block_size * ctx.rsn);
+	if (!buf) {
+		log_err(cd, _("Failed to allocate buffer."));
+		r = -ENOMEM;
+		goto out;
+	}
+
+	/* encode/decode input */
+	for (n = 0; n < ctx.rounds; ++n) {
+		for (i = 0; i < ctx.rsn; ++i) {
+			if (FEC_read_interleaved(&ctx, n * ctx.rsn * ctx.block_size + i,
+						 &buf[i * ctx.block_size], ctx.block_size)) {
+				log_err(cd, _("Failed to read RS block %" PRIu64 " byte %d."), n, i);
+				r = -EIO;
+				goto out;
+			}
+		}
+
+		for (b = 0; b < ctx.block_size; ++b) {
+			for (i = 0; i < ctx.rsn; ++i)
+				rs_block[i] = buf[i * ctx.block_size + b];
+
+			/* decoding from parity device */
+			if (decode) {
+				if (read_buffer(fd, &rs_block[ctx.rsn], ctx.roots) != ctx.roots) {
+					log_err(cd, _("Failed to read parity for RS block %" PRIu64 "."), n);
+					r = -EIO;
+					goto out;
+				}
+
+				/* coverity[tainted_data] */
+				r = decode_rs_char(rs, rs_block);
+				if (r < 0) {
+					log_err(cd, _("Failed to repair parity for block %" PRIu64 "."), n);
+					goto out;
+				}
+				/* return number of detected errors */
+				if (errors)
+					*errors += r;
+				r = 0;
+			} else {
+				/* encoding and writing parity data to fec device */
+				encode_rs_char(rs, rs_block, &rs_block[ctx.rsn]);
+				if (write_buffer(fd, &rs_block[ctx.rsn], ctx.roots) != ctx.roots) {
+					log_err(cd, _("Failed to write parity for RS block %" PRIu64 "."), n);
+					r = -EIO;
+					goto out;
+				}
+			}
+		}
+	}
+out:
+	free_rs_char(rs);
+	free(buf);
+	return r;
+}
+
+int VERITY_FEC_process(struct crypt_device *cd,
+		      struct crypt_params_verity *params,
+		      struct device *fec_device, int check_fec,
+		      unsigned int *errors)
+{
+	int r;
+	int fd = -1;
+	struct fec_input_device inputs[FEC_INPUT_DEVICES] = {
+		{
+			.device = crypt_data_device(cd),
+			.fd = -1,
+			.start = 0,
+			.count =  params->data_size * params->data_block_size
+		},{
+			.device = crypt_metadata_device(cd),
+			.fd = -1,
+			.start = VERITY_hash_offset_block(params) * params->data_block_size
+		}
+	};
+
+	/* validate parameters */
+	if (params->data_block_size != params->hash_block_size) {
+		log_err(cd, _("Block sizes must match for FEC."));
+		return -EINVAL;
+	}
+
+	if (params->fec_roots > FEC_RSM - FEC_MIN_RSN ||
+		params->fec_roots < FEC_RSM - FEC_MAX_RSN) {
+		log_err(cd, _("Invalid number of parity bytes."));
+		return -EINVAL;
+	}
+
+	r = -EIO;
+
+	if (check_fec)
+		fd = open(device_path(fec_device), O_RDONLY);
+	else
+		fd = open(device_path(fec_device), O_RDWR);
+
+	if (fd == -1) {
+		log_err(cd, _("Cannot open device %s."), device_path(fec_device));
+		goto out;
+	}
+
+	if (lseek(fd, params->fec_area_offset, SEEK_SET) < 0) {
+		log_dbg(cd, "Cannot seek to requested position in FEC device.");
+		goto out;
+	}
+
+	/* input devices */
+	inputs[0].fd = open(device_path(inputs[0].device), O_RDONLY);
+	if (inputs[0].fd == -1) {
+		log_err(cd, _("Cannot open device %s."), device_path(inputs[0].device));
+		goto out;
+	}
+	inputs[1].fd = open(device_path(inputs[1].device), O_RDONLY);
+	if (inputs[1].fd == -1) {
+		log_err(cd, _("Cannot open device %s."), device_path(inputs[1].device));
+		goto out;
+	}
+
+	/* cover the entire hash device starting from hash_offset */
+	r = device_size(inputs[1].device, &inputs[1].count);
+	if (r) {
+		log_err(cd, _("Failed to determine size for device %s."),
+				device_path(inputs[1].device));
+		goto out;
+	}
+	inputs[1].count -= inputs[1].start;
+
+	r = FEC_process_inputs(cd, params, inputs, FEC_INPUT_DEVICES, fd, check_fec, errors);
+out:
+	if (inputs[0].fd != -1)
+		close(inputs[0].fd);
+	if (inputs[1].fd != -1)
+		close(inputs[1].fd);
+	if (fd != -1)
+		close(fd);
+
+	return r;
+}