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2023-12-11 072de836f53be56a70cecf70b43ae43b7ce17376 
 kernel/fs/ubifs/io.c
....@@ -1,21 +1,9 @@
1
+// SPDX-License-Identifier: GPL-2.0-only
12 /*
23  * This file is part of UBIFS.
34  *
45  * Copyright (C) 2006-2008 Nokia Corporation.
56  * Copyright (C) 2006, 2007 University of Szeged, Hungary
6
- *
7
- * This program is free software; you can redistribute it and/or modify it
8
- * under the terms of the GNU General Public License version 2 as published by
9
- * the Free Software Foundation.
10
- *
11
- * This program is distributed in the hope that it will be useful, but WITHOUT
12
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
14
- * more details.
15
- *
16
- * You should have received a copy of the GNU General Public License along with
17
- * this program; if not, write to the Free Software Foundation, Inc., 51
18
- * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
197  *
208  * Authors: Artem Bityutskiy (Битюцкий Артём)
219  *          Adrian Hunter
....@@ -377,6 +365,68 @@
377365 	return sqnum;
378366 }
379367 
368
+void ubifs_init_node(struct ubifs_info *c, void *node, int len, int pad)
369
+{
370
+	struct ubifs_ch *ch = node;
371
+	unsigned long long sqnum = next_sqnum(c);
372
+
373
+	ubifs_assert(c, len >= UBIFS_CH_SZ);
374
+
375
+	ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
376
+	ch->len = cpu_to_le32(len);
377
+	ch->group_type = UBIFS_NO_NODE_GROUP;
378
+	ch->sqnum = cpu_to_le64(sqnum);
379
+	ch->padding[0] = ch->padding[1] = 0;
380
+
381
+	if (pad) {
382
+		len = ALIGN(len, 8);
383
+		pad = ALIGN(len, c->min_io_size) - len;
384
+		ubifs_pad(c, node + len, pad);
385
+	}
386
+}
387
+
388
+void ubifs_crc_node(struct ubifs_info *c, void *node, int len)
389
+{
390
+	struct ubifs_ch *ch = node;
391
+	uint32_t crc;
392
+
393
+	crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);
394
+	ch->crc = cpu_to_le32(crc);
395
+}
396
+
397
+/**
398
+ * ubifs_prepare_node_hmac - prepare node to be written to flash.
399
+ * @c: UBIFS file-system description object
400
+ * @node: the node to pad
401
+ * @len: node length
402
+ * @hmac_offs: offset of the HMAC in the node
403
+ * @pad: if the buffer has to be padded
404
+ *
405
+ * This function prepares node at @node to be written to the media - it
406
+ * calculates node CRC, fills the common header, and adds proper padding up to
407
+ * the next minimum I/O unit if @pad is not zero. if @hmac_offs is positive then
408
+ * a HMAC is inserted into the node at the given offset.
409
+ *
410
+ * This function returns 0 for success or a negative error code otherwise.
411
+ */
412
+int ubifs_prepare_node_hmac(struct ubifs_info *c, void *node, int len,
413
+			    int hmac_offs, int pad)
414
+{
415
+	int err;
416
+
417
+	ubifs_init_node(c, node, len, pad);
418
+
419
+	if (hmac_offs > 0) {
420
+		err = ubifs_node_insert_hmac(c, node, len, hmac_offs);
421
+		if (err)
422
+			return err;
423
+	}
424
+
425
+	ubifs_crc_node(c, node, len);
426
+
427
+	return 0;
428
+}
429
+
380430 /**
381431  * ubifs_prepare_node - prepare node to be written to flash.
382432  * @c: UBIFS file-system description object
....@@ -390,25 +440,11 @@
390440  */
391441 void ubifs_prepare_node(struct ubifs_info *c, void *node, int len, int pad)
392442 {
393
-	uint32_t crc;
394
-	struct ubifs_ch *ch = node;
395
-	unsigned long long sqnum = next_sqnum(c);
396
-
397
-	ubifs_assert(c, len >= UBIFS_CH_SZ);
398
-
399
-	ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
400
-	ch->len = cpu_to_le32(len);
401
-	ch->group_type = UBIFS_NO_NODE_GROUP;
402
-	ch->sqnum = cpu_to_le64(sqnum);
403
-	ch->padding[0] = ch->padding[1] = 0;
404
-	crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);
405
-	ch->crc = cpu_to_le32(crc);
406
-
407
-	if (pad) {
408
-		len = ALIGN(len, 8);
409
-		pad = ALIGN(len, c->min_io_size) - len;
410
-		ubifs_pad(c, node + len, pad);
411
-	}
443
+	/*
444
+	 * Deliberately ignore return value since this function can only fail
445
+	 * when a hmac offset is given.
446
+	 */
447
+	ubifs_prepare_node_hmac(c, node, len, 0, pad);
412448 }
413449 
414450 /**
....@@ -810,16 +846,42 @@
810846 	 */
811847 	n = aligned_len >> c->max_write_shift;
812848 	if (n) {
813
-		n <<= c->max_write_shift;
849
+		int m = n - 1;
850
+
814851 		dbg_io("write %d bytes to LEB %d:%d", n, wbuf->lnum,
815852 		       wbuf->offs);
816
-		err = ubifs_leb_write(c, wbuf->lnum, buf + written,
817
-				      wbuf->offs, n);
853
+
854
+		if (m) {
855
+			/* '(n-1)<<c->max_write_shift < len' is always true. */
856
+			m <<= c->max_write_shift;
857
+			err = ubifs_leb_write(c, wbuf->lnum, buf + written,
858
+					      wbuf->offs, m);
859
+			if (err)
860
+				goto out;
861
+			wbuf->offs += m;
862
+			aligned_len -= m;
863
+			len -= m;
864
+			written += m;
865
+		}
866
+
867
+		/*
868
+		 * The non-written len of buf may be less than 'n' because
869
+		 * parameter 'len' is not 8 bytes aligned, so here we read
870
+		 * min(len, n) bytes from buf.
871
+		 */
872
+		n = 1 << c->max_write_shift;
873
+		memcpy(wbuf->buf, buf + written, min(len, n));
874
+		if (n > len) {
875
+			ubifs_assert(c, n - len < 8);
876
+			ubifs_pad(c, wbuf->buf + len, n - len);
877
+		}
878
+
879
+		err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, wbuf->offs, n);
818880 		if (err)
819881 			goto out;
820882 		wbuf->offs += n;
821883 		aligned_len -= n;
822
-		len -= n;
884
+		len -= min(len, n);
823885 		written += n;
824886 	}
825887 
....@@ -870,6 +932,48 @@
870932 }
871933 
872934 /**
935
+ * ubifs_write_node_hmac - write node to the media.
936
+ * @c: UBIFS file-system description object
937
+ * @buf: the node to write
938
+ * @len: node length
939
+ * @lnum: logical eraseblock number
940
+ * @offs: offset within the logical eraseblock
941
+ * @hmac_offs: offset of the HMAC within the node
942
+ *
943
+ * This function automatically fills node magic number, assigns sequence
944
+ * number, and calculates node CRC checksum. The length of the @buf buffer has
945
+ * to be aligned to the minimal I/O unit size. This function automatically
946
+ * appends padding node and padding bytes if needed. Returns zero in case of
947
+ * success and a negative error code in case of failure.
948
+ */
949
+int ubifs_write_node_hmac(struct ubifs_info *c, void *buf, int len, int lnum,
950
+			  int offs, int hmac_offs)
951
+{
952
+	int err, buf_len = ALIGN(len, c->min_io_size);
953
+
954
+	dbg_io("LEB %d:%d, %s, length %d (aligned %d)",
955
+	       lnum, offs, dbg_ntype(((struct ubifs_ch *)buf)->node_type), len,
956
+	       buf_len);
957
+	ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
958
+	ubifs_assert(c, offs % c->min_io_size == 0 && offs < c->leb_size);
959
+	ubifs_assert(c, !c->ro_media && !c->ro_mount);
960
+	ubifs_assert(c, !c->space_fixup);
961
+
962
+	if (c->ro_error)
963
+		return -EROFS;
964
+
965
+	err = ubifs_prepare_node_hmac(c, buf, len, hmac_offs, 1);
966
+	if (err)
967
+		return err;
968
+
969
+	err = ubifs_leb_write(c, lnum, buf, offs, buf_len);
970
+	if (err)
971
+		ubifs_dump_node(c, buf);
972
+
973
+	return err;
974
+}
975
+
976
+/**
873977  * ubifs_write_node - write node to the media.
874978  * @c: UBIFS file-system description object
875979  * @buf: the node to write
....@@ -886,25 +990,7 @@
886990 int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum,
887991 		     int offs)
888992 {
889
-	int err, buf_len = ALIGN(len, c->min_io_size);
890
-
891
-	dbg_io("LEB %d:%d, %s, length %d (aligned %d)",
892
-	       lnum, offs, dbg_ntype(((struct ubifs_ch *)buf)->node_type), len,
893
-	       buf_len);
894
-	ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
895
-	ubifs_assert(c, offs % c->min_io_size == 0 && offs < c->leb_size);
896
-	ubifs_assert(c, !c->ro_media && !c->ro_mount);
897
-	ubifs_assert(c, !c->space_fixup);
898
-
899
-	if (c->ro_error)
900
-		return -EROFS;
901
-
902
-	ubifs_prepare_node(c, buf, len, 1);
903
-	err = ubifs_leb_write(c, lnum, buf, offs, buf_len);
904
-	if (err)
905
-		ubifs_dump_node(c, buf);
906
-
907
-	return err;
993
+	return ubifs_write_node_hmac(c, buf, len, lnum, offs, -1);
908994 }
909995 
910996 /**