Issue #1859 - Part 1: Update xz-embedded library.

This also updates the script for updating and README.

12 files changed, 454 insertions, 33 deletions

diff --git a/modules/xz-embedded/README.mozilla b/modules/xz-embedded/README.mozilla
index d0532e1e91..17dd755ee4 100644
--- a/modules/xz-embedded/README.mozilla
+++ b/modules/xz-embedded/README.mozilla
@@ -1,14 +1,14 @@
 This is the XZ Embedded decompression library from
-http://tukaani.org/xz/embedded.html.
+https://tukaani.org/xz/embedded.html.
 
 Upstream code can be viewed at
-  http://git.tukaani.org/xz-embedded.git
+  https://git.tukaani.org/xz-embedded.git
 
 and cloned by
-  git clone http://git.tukaani.org/xz-embedded.git
+  git clone https://git.tukaani.org/xz-embedded.git
 
 The in-tree copy is updated by running
   sh update.sh
 from within the modules/xz-embedded directory.
 
-Current version: [e75f4eb79165213a02d567940d344f5c2ff1be03].
+Current version: [3f438e15109229bb14ab45f285f4bff5412a9542].
diff --git a/modules/xz-embedded/src/xz.h b/modules/xz-embedded/src/xz.h
index 0a4b38d33c..f3801eb6f5 100644
--- a/modules/xz-embedded/src/xz.h
+++ b/modules/xz-embedded/src/xz.h
@@ -2,7 +2,7 @@
  * XZ decompressor
  *
  * Authors: Lasse Collin <lasse.collin@tukaani.org>
- *          Igor Pavlov <http://7-zip.org/>
+ *          Igor Pavlov <https://7-zip.org/>
  *
  * This file has been put into the public domain.
  * You can do whatever you want with this file.
@@ -32,7 +32,7 @@ extern "C" {
  * enum xz_mode - Operation mode
  *
  * @XZ_SINGLE:              Single-call mode. This uses less RAM than
- *                          than multi-call modes, because the LZMA2
+ *                          multi-call modes, because the LZMA2
  *                          dictionary doesn't need to be allocated as
  *                          part of the decoder state. All required data
  *                          structures are allocated at initialization,
@@ -198,7 +198,7 @@ struct xz_dec;
 XZ_EXTERN struct xz_dec *xz_dec_init(enum xz_mode mode, uint32_t dict_max);
 
 /**
- * xz_dec_run() - Run the XZ decoder
+ * xz_dec_run() - Run the XZ decoder for a single XZ stream
  * @s:          Decoder state allocated using xz_dec_init()
  * @b:          Input and output buffers
  *
@@ -214,10 +214,52 @@ XZ_EXTERN struct xz_dec *xz_dec_init(enum xz_mode mode, uint32_t dict_max);
  * cannot give the single-call decoder a too small buffer and then expect to
  * get that amount valid data from the beginning of the stream. You must use
  * the multi-call decoder if you don't want to uncompress the whole stream.
+ *
+ * Use xz_dec_run() when XZ data is stored inside some other file format.
+ * The decoding will stop after one XZ stream has been decompresed. To
+ * decompress regular .xz files which might have multiple concatenated
+ * streams, use xz_dec_catrun() instead.
  */
 XZ_EXTERN enum xz_ret xz_dec_run(struct xz_dec *s, struct xz_buf *b);
 
 /**
+ * xz_dec_catrun() - Run the XZ decoder with support for concatenated streams
+ * @s:          Decoder state allocated using xz_dec_init()
+ * @b:          Input and output buffers
+ * @finish:     This is an int instead of bool to avoid requiring stdbool.h.
+ *              As long as more input might be coming, finish must be false.
+ *              When the caller knows that it has provided all the input to
+ *              the decoder (some possibly still in b->in), it must set finish
+ *              to true. Only when finish is true can this function return
+ *              XZ_STREAM_END to indicate successful decompression of the
+ *              file. In single-call mode (XZ_SINGLE) finish is assumed to
+ *              always be true; the caller-provided value is ignored.
+ *
+ * This is like xz_dec_run() except that this makes it easy to decode .xz
+ * files with multiple streams (multiple .xz files concatenated as is).
+ * The rarely-used Stream Padding feature is supported too, that is, there
+ * can be null bytes after or between the streams. The number of null bytes
+ * must be a multiple of four.
+ *
+ * When finish is false and b->in_pos == b->in_size, it is possible that
+ * XZ_BUF_ERROR isn't returned even when no progress is possible (XZ_OK is
+ * returned instead). This shouldn't matter because in this situation a
+ * reasonable caller will attempt to provide more input or set finish to
+ * true for the next xz_dec_catrun() call anyway.
+ *
+ * For any struct xz_dec that has been initialized for multi-call mode:
+ * Once decoding has been started with xz_dec_run() or xz_dec_catrun(),
+ * the same function must be used until xz_dec_reset() or xz_dec_end().
+ * Switching between the two decoding functions without resetting results
+ * in undefined behavior.
+ *
+ * xz_dec_catrun() is only available if XZ_DEC_CONCATENATED was defined
+ * at compile time.
+ */
+XZ_EXTERN enum xz_ret xz_dec_catrun(struct xz_dec *s, struct xz_buf *b,
+				    int finish);
+
+/**
  * xz_dec_reset() - Reset an already allocated decoder state
  * @s:          Decoder state allocated using xz_dec_init()
  *
@@ -238,6 +280,112 @@ XZ_EXTERN void xz_dec_reset(struct xz_dec *s);
 XZ_EXTERN void xz_dec_end(struct xz_dec *s);
 
 /*
+ * Decompressor for MicroLZMA, an LZMA variant with a very minimal header.
+ * See xz_dec_microlzma_alloc() below for details.
+ *
+ * These functions aren't used or available in preboot code and thus aren't
+ * marked with XZ_EXTERN. This avoids warnings about static functions that
+ * are never defined.
+ */
+/**
+ * struct xz_dec_microlzma - Opaque type to hold the MicroLZMA decoder state
+ */
+struct xz_dec_microlzma;
+
+/**
+ * xz_dec_microlzma_alloc() - Allocate memory for the MicroLZMA decoder
+ * @mode        XZ_SINGLE or XZ_PREALLOC
+ * @dict_size   LZMA dictionary size. This must be at least 4 KiB and
+ *              at most 3 GiB.
+ *
+ * In contrast to xz_dec_init(), this function only allocates the memory
+ * and remembers the dictionary size. xz_dec_microlzma_reset() must be used
+ * before calling xz_dec_microlzma_run().
+ *
+ * The amount of allocated memory is a little less than 30 KiB with XZ_SINGLE.
+ * With XZ_PREALLOC also a dictionary buffer of dict_size bytes is allocated.
+ *
+ * On success, xz_dec_microlzma_alloc() returns a pointer to
+ * struct xz_dec_microlzma. If memory allocation fails or
+ * dict_size is invalid, NULL is returned.
+ *
+ * The compressed format supported by this decoder is a raw LZMA stream
+ * whose first byte (always 0x00) has been replaced with bitwise-negation
+ * of the LZMA properties (lc/lp/pb) byte. For example, if lc/lp/pb is
+ * 3/0/2, the first byte is 0xA2. This way the first byte can never be 0x00.
+ * Just like with LZMA2, lc + lp <= 4 must be true. The LZMA end-of-stream
+ * marker must not be used. The unused values are reserved for future use.
+ * This MicroLZMA header format was created for use in EROFS but may be used
+ * by others too.
+ */
+extern struct xz_dec_microlzma *xz_dec_microlzma_alloc(enum xz_mode mode,
+						       uint32_t dict_size);
+
+/**
+ * xz_dec_microlzma_reset() - Reset the MicroLZMA decoder state
+ * @s           Decoder state allocated using xz_dec_microlzma_alloc()
+ * @comp_size   Compressed size of the input stream
+ * @uncomp_size Uncompressed size of the input stream. A value smaller
+ *              than the real uncompressed size of the input stream can
+ *              be specified if uncomp_size_is_exact is set to false.
+ *              uncomp_size can never be set to a value larger than the
+ *              expected real uncompressed size because it would eventually
+ *              result in XZ_DATA_ERROR.
+ * @uncomp_size_is_exact  This is an int instead of bool to avoid
+ *              requiring stdbool.h. This should normally be set to true.
+ *              When this is set to false, error detection is weaker.
+ */
+extern void xz_dec_microlzma_reset(struct xz_dec_microlzma *s,
+				   uint32_t comp_size, uint32_t uncomp_size,
+				   int uncomp_size_is_exact);
+
+/**
+ * xz_dec_microlzma_run() - Run the MicroLZMA decoder
+ * @s           Decoder state initialized using xz_dec_microlzma_reset()
+ * @b:          Input and output buffers
+ *
+ * This works similarly to xz_dec_run() with a few important differences.
+ * Only the differences are documented here.
+ *
+ * The only possible return values are XZ_OK, XZ_STREAM_END, and
+ * XZ_DATA_ERROR. This function cannot return XZ_BUF_ERROR: if no progress
+ * is possible due to lack of input data or output space, this function will
+ * keep returning XZ_OK. Thus, the calling code must be written so that it
+ * will eventually provide input and output space matching (or exceeding)
+ * comp_size and uncomp_size arguments given to xz_dec_microlzma_reset().
+ * If the caller cannot do this (for example, if the input file is truncated
+ * or otherwise corrupt), the caller must detect this error by itself to
+ * avoid an infinite loop.
+ *
+ * If the compressed data seems to be corrupt, XZ_DATA_ERROR is returned.
+ * This can happen also when incorrect dictionary, uncompressed, or
+ * compressed sizes have been specified.
+ *
+ * With XZ_PREALLOC only: As an extra feature, b->out may be NULL to skip over
+ * uncompressed data. This way the caller doesn't need to provide a temporary
+ * output buffer for the bytes that will be ignored.
+ *
+ * With XZ_SINGLE only: In contrast to xz_dec_run(), the return value XZ_OK
+ * is also possible and thus XZ_SINGLE is actually a limited multi-call mode.
+ * After XZ_OK the bytes decoded so far may be read from the output buffer.
+ * It is possible to continue decoding but the variables b->out and b->out_pos
+ * MUST NOT be changed by the caller. Increasing the value of b->out_size is
+ * allowed to make more output space available; one doesn't need to provide
+ * space for the whole uncompressed data on the first call. The input buffer
+ * may be changed normally like with XZ_PREALLOC. This way input data can be
+ * provided from non-contiguous memory.
+ */
+extern enum xz_ret xz_dec_microlzma_run(struct xz_dec_microlzma *s,
+					struct xz_buf *b);
+
+/**
+ * xz_dec_microlzma_end() - Free the memory allocated for the decoder state
+ * @s:          Decoder state allocated using xz_dec_microlzma_alloc().
+ *              If s is NULL, this function does nothing.
+ */
+extern void xz_dec_microlzma_end(struct xz_dec_microlzma *s);
+
+/*
  * Standalone build (userspace build or in-kernel build for boot time use)
  * needs a CRC32 implementation. For normal in-kernel use, kernel's own
  * CRC32 module is used instead, and users of this module don't need to
diff --git a/modules/xz-embedded/src/xz_config.h b/modules/xz-embedded/src/xz_config.h
index eb9dac1a4b..ee590d7ea6 100644
--- a/modules/xz-embedded/src/xz_config.h
+++ b/modules/xz-embedded/src/xz_config.h
@@ -10,6 +10,9 @@
 #ifndef XZ_CONFIG_H
 #define XZ_CONFIG_H
 
+/* Uncomment to enable building of xz_dec_catrun(). */
+/* #define XZ_DEC_CONCATENATED */
+
 /* Uncomment to enable CRC64 support. */
 /* #define XZ_USE_CRC64 */
 
diff --git a/modules/xz-embedded/src/xz_crc32.c b/modules/xz-embedded/src/xz_crc32.c
index 34532d14fd..5627b00fca 100644
--- a/modules/xz-embedded/src/xz_crc32.c
+++ b/modules/xz-embedded/src/xz_crc32.c
@@ -2,7 +2,7 @@
  * CRC32 using the polynomial from IEEE-802.3
  *
  * Authors: Lasse Collin <lasse.collin@tukaani.org>
- *          Igor Pavlov <http://7-zip.org/>
+ *          Igor Pavlov <https://7-zip.org/>
  *
  * This file has been put into the public domain.
  * You can do whatever you want with this file.
diff --git a/modules/xz-embedded/src/xz_crc64.c b/modules/xz-embedded/src/xz_crc64.c
index ca1caee899..60c40f67e7 100644
--- a/modules/xz-embedded/src/xz_crc64.c
+++ b/modules/xz-embedded/src/xz_crc64.c
@@ -4,7 +4,7 @@
  * This file is similar to xz_crc32.c. See the comments there.
  *
  * Authors: Lasse Collin <lasse.collin@tukaani.org>
- *          Igor Pavlov <http://7-zip.org/>
+ *          Igor Pavlov <https://7-zip.org/>
  *
  * This file has been put into the public domain.
  * You can do whatever you want with this file.
@@ -20,7 +20,11 @@ STATIC_RW_DATA uint64_t xz_crc64_table[256];
 
 XZ_EXTERN void xz_crc64_init(void)
 {
-	const uint64_t poly = 0xC96C5795D7870F42;
+	/*
+	 * The ULL suffix is needed for -std=gnu89 compatibility
+	 * on 32-bit platforms.
+	 */
+	const uint64_t poly = 0xC96C5795D7870F42ULL;
 
 	uint32_t i;
 	uint32_t j;
diff --git a/modules/xz-embedded/src/xz_dec_bcj.c b/modules/xz-embedded/src/xz_dec_bcj.c
index a768e6d28b..ef449e97d1 100644
--- a/modules/xz-embedded/src/xz_dec_bcj.c
+++ b/modules/xz-embedded/src/xz_dec_bcj.c
@@ -2,7 +2,7 @@
  * Branch/Call/Jump (BCJ) filter decoders
  *
  * Authors: Lasse Collin <lasse.collin@tukaani.org>
- *          Igor Pavlov <http://7-zip.org/>
+ *          Igor Pavlov <https://7-zip.org/>
  *
  * This file has been put into the public domain.
  * You can do whatever you want with this file.
@@ -422,7 +422,7 @@ XZ_EXTERN enum xz_ret xz_dec_bcj_run(struct xz_dec_bcj *s,
 
 	/*
 	 * Flush pending already filtered data to the output buffer. Return
-	 * immediatelly if we couldn't flush everything, or if the next
+	 * immediately if we couldn't flush everything, or if the next
 	 * filter in the chain had already returned XZ_STREAM_END.
 	 */
 	if (s->temp.filtered > 0) {
diff --git a/modules/xz-embedded/src/xz_dec_lzma2.c b/modules/xz-embedded/src/xz_dec_lzma2.c
index 08c3c80499..c929f1c82b 100644
--- a/modules/xz-embedded/src/xz_dec_lzma2.c
+++ b/modules/xz-embedded/src/xz_dec_lzma2.c
@@ -2,7 +2,7 @@
  * LZMA2 decoder
  *
  * Authors: Lasse Collin <lasse.collin@tukaani.org>
- *          Igor Pavlov <http://7-zip.org/>
+ *          Igor Pavlov <https://7-zip.org/>
  *
  * This file has been put into the public domain.
  * You can do whatever you want with this file.
@@ -147,8 +147,8 @@ struct lzma_dec {
 
 	/*
 	 * LZMA properties or related bit masks (number of literal
-	 * context bits, a mask dervied from the number of literal
-	 * position bits, and a mask dervied from the number
+	 * context bits, a mask derived from the number of literal
+	 * position bits, and a mask derived from the number
 	 * position bits)
 	 */
 	uint32_t lc;
@@ -248,6 +248,10 @@ struct lzma2_dec {
 	 * before the first LZMA chunk.
 	 */
 	bool need_props;
+
+#ifdef XZ_DEC_MICROLZMA
+	bool pedantic_microlzma;
+#endif
 };
 
 struct xz_dec_lzma2 {
@@ -387,7 +391,14 @@ static void dict_uncompressed(struct dictionary *dict, struct xz_buf *b,
 
 		*left -= copy_size;
 
-		memcpy(dict->buf + dict->pos, b->in + b->in_pos, copy_size);
+		/*
+		 * If doing in-place decompression in single-call mode and the
+		 * uncompressed size of the file is larger than the caller
+		 * thought (i.e. it is invalid input!), the buffers below may
+		 * overlap and cause undefined behavior with memcpy().
+		 * With valid inputs memcpy() would be fine here.
+		 */
+		memmove(dict->buf + dict->pos, b->in + b->in_pos, copy_size);
 		dict->pos += copy_size;
 
 		if (dict->full < dict->pos)
@@ -397,7 +408,11 @@ static void dict_uncompressed(struct dictionary *dict, struct xz_buf *b,
 			if (dict->pos == dict->end)
 				dict->pos = 0;
 
-			memcpy(b->out + b->out_pos, b->in + b->in_pos,
+			/*
+			 * Like above but for multi-call mode: use memmove()
+			 * to avoid undefined behavior with invalid input.
+			 */
+			memmove(b->out + b->out_pos, b->in + b->in_pos,
 					copy_size);
 		}
 
@@ -408,6 +423,12 @@ static void dict_uncompressed(struct dictionary *dict, struct xz_buf *b,
 	}
 }
 
+#ifdef XZ_DEC_MICROLZMA
+#	define DICT_FLUSH_SUPPORTS_SKIPPING true
+#else
+#	define DICT_FLUSH_SUPPORTS_SKIPPING false
+#endif
+
 /*
  * Flush pending data from dictionary to b->out. It is assumed that there is
  * enough space in b->out. This is guaranteed because caller uses dict_limit()
@@ -421,8 +442,19 @@ static uint32_t dict_flush(struct dictionary *dict, struct xz_buf *b)
 		if (dict->pos == dict->end)
 			dict->pos = 0;
 
-		memcpy(b->out + b->out_pos, dict->buf + dict->start,
-				copy_size);
+		/*
+		 * These buffers cannot overlap even if doing in-place
+		 * decompression because in multi-call mode dict->buf
+		 * has been allocated by us in this file; it's not
+		 * provided by the caller like in single-call mode.
+		 *
+		 * With MicroLZMA, b->out can be NULL to skip bytes that
+		 * the caller doesn't need. This cannot be done with XZ
+		 * because it would break BCJ filters.
+		 */
+		if (!DICT_FLUSH_SUPPORTS_SKIPPING || b->out != NULL)
+			memcpy(b->out + b->out_pos, dict->buf + dict->start,
+					copy_size);
 	}
 
 	dict->start = dict->pos;
@@ -484,11 +516,11 @@ static __always_inline void rc_normalize(struct rc_dec *rc)
 }
 
 /*
- * Decode one bit. In some versions, this function has been splitted in three
+ * Decode one bit. In some versions, this function has been split in three
  * functions so that the compiler is supposed to be able to more easily avoid
  * an extra branch. In this particular version of the LZMA decoder, this
  * doesn't seem to be a good idea (tested with GCC 3.3.6, 3.4.6, and 4.3.3
- * on x86). Using a non-splitted version results in nicer looking code too.
+ * on x86). Using a non-split version results in nicer looking code too.
  *
  * NOTE: This must return an int. Do not make it return a bool or the speed
  * of the code generated by GCC 3.x decreases 10-15 %. (GCC 4.3 doesn't care,
@@ -761,7 +793,7 @@ static bool lzma_main(struct xz_dec_lzma2 *s)
 }
 
 /*
- * Reset the LZMA decoder and range decoder state. Dictionary is nore reset
+ * Reset the LZMA decoder and range decoder state. Dictionary is not reset
  * here, because LZMA state may be reset without resetting the dictionary.
  */
 static void lzma_reset(struct xz_dec_lzma2 *s)
@@ -774,6 +806,7 @@ static void lzma_reset(struct xz_dec_lzma2 *s)
 	s->lzma.rep1 = 0;
 	s->lzma.rep2 = 0;
 	s->lzma.rep3 = 0;
+	s->lzma.len = 0;
 
 	/*
 	 * All probabilities are initialized to the same value. This hack
@@ -1146,6 +1179,7 @@ XZ_EXTERN enum xz_ret xz_dec_lzma2_reset(struct xz_dec_lzma2 *s, uint8_t props)
 
 		if (DEC_IS_DYNALLOC(s->dict.mode)) {
 			if (s->dict.allocated < s->dict.size) {
+				s->dict.allocated = s->dict.size;
 				vfree(s->dict.buf);
 				s->dict.buf = vmalloc(s->dict.size);
 				if (s->dict.buf == NULL) {
@@ -1156,8 +1190,6 @@ XZ_EXTERN enum xz_ret xz_dec_lzma2_reset(struct xz_dec_lzma2 *s, uint8_t props)
 		}
 	}
 
-	s->lzma.len = 0;
-
 	s->lzma2.sequence = SEQ_CONTROL;
 	s->lzma2.need_dict_reset = true;
 
@@ -1173,3 +1205,140 @@ XZ_EXTERN void xz_dec_lzma2_end(struct xz_dec_lzma2 *s)
 
 	kfree(s);
 }
+
+#ifdef XZ_DEC_MICROLZMA
+/* This is a wrapper struct to have a nice struct name in the public API. */
+struct xz_dec_microlzma {
+	struct xz_dec_lzma2 s;
+};
+
+enum xz_ret xz_dec_microlzma_run(struct xz_dec_microlzma *s_ptr,
+				 struct xz_buf *b)
+{
+	struct xz_dec_lzma2 *s = &s_ptr->s;
+
+	/*
+	 * sequence is SEQ_PROPERTIES before the first input byte,
+	 * SEQ_LZMA_PREPARE until a total of five bytes have been read,
+	 * and SEQ_LZMA_RUN for the rest of the input stream.
+	 */
+	if (s->lzma2.sequence != SEQ_LZMA_RUN) {
+		if (s->lzma2.sequence == SEQ_PROPERTIES) {
+			/* One byte is needed for the props. */
+			if (b->in_pos >= b->in_size)
+				return XZ_OK;
+
+			/*
+			 * Don't increment b->in_pos here. The same byte is
+			 * also passed to rc_read_init() which will ignore it.
+			 */
+			if (!lzma_props(s, ~b->in[b->in_pos]))
+				return XZ_DATA_ERROR;
+
+			s->lzma2.sequence = SEQ_LZMA_PREPARE;
+		}
+
+		/*
+		 * xz_dec_microlzma_reset() doesn't validate the compressed
+		 * size so we do it here. We have to limit the maximum size
+		 * to avoid integer overflows in lzma2_lzma(). 3 GiB is a nice
+		 * round number and much more than users of this code should
+		 * ever need.
+		 */
+		if (s->lzma2.compressed < RC_INIT_BYTES
+				|| s->lzma2.compressed > (3U << 30))
+			return XZ_DATA_ERROR;
+
+		if (!rc_read_init(&s->rc, b))
+			return XZ_OK;
+
+		s->lzma2.compressed -= RC_INIT_BYTES;
+		s->lzma2.sequence = SEQ_LZMA_RUN;
+
+		dict_reset(&s->dict, b);
+	}
+
+	/* This is to allow increasing b->out_size between calls. */
+	if (DEC_IS_SINGLE(s->dict.mode))
+		s->dict.end = b->out_size - b->out_pos;
+
+	while (true) {
+		dict_limit(&s->dict, min_t(size_t, b->out_size - b->out_pos,
+					   s->lzma2.uncompressed));
+
+		if (!lzma2_lzma(s, b))
+			return XZ_DATA_ERROR;
+
+		s->lzma2.uncompressed -= dict_flush(&s->dict, b);
+
+		if (s->lzma2.uncompressed == 0) {
+			if (s->lzma2.pedantic_microlzma) {
+				if (s->lzma2.compressed > 0 || s->lzma.len > 0
+						|| !rc_is_finished(&s->rc))
+					return XZ_DATA_ERROR;
+			}
+
+			return XZ_STREAM_END;
+		}
+
+		if (b->out_pos == b->out_size)
+			return XZ_OK;
+
+		if (b->in_pos == b->in_size
+				&& s->temp.size < s->lzma2.compressed)
+			return XZ_OK;
+	}
+}
+
+struct xz_dec_microlzma *xz_dec_microlzma_alloc(enum xz_mode mode,
+						uint32_t dict_size)
+{
+	struct xz_dec_microlzma *s;
+
+	/* Restrict dict_size to the same range as in the LZMA2 code. */
+	if (dict_size < 4096 || dict_size > (3U << 30))
+		return NULL;
+
+	s = kmalloc(sizeof(*s), GFP_KERNEL);
+	if (s == NULL)
+		return NULL;
+
+	s->s.dict.mode = mode;
+	s->s.dict.size = dict_size;
+
+	if (DEC_IS_MULTI(mode)) {
+		s->s.dict.end = dict_size;
+
+		s->s.dict.buf = vmalloc(dict_size);
+		if (s->s.dict.buf == NULL) {
+			kfree(s);
+			return NULL;
+		}
+	}
+
+	return s;
+}
+
+void xz_dec_microlzma_reset(struct xz_dec_microlzma *s, uint32_t comp_size,
+			    uint32_t uncomp_size, int uncomp_size_is_exact)
+{
+	/*
+	 * comp_size is validated in xz_dec_microlzma_run().
+	 * uncomp_size can safely be anything.
+	 */
+	s->s.lzma2.compressed = comp_size;
+	s->s.lzma2.uncompressed = uncomp_size;
+	s->s.lzma2.pedantic_microlzma = uncomp_size_is_exact;
+
+	s->s.lzma2.sequence = SEQ_PROPERTIES;
+	s->s.temp.size = 0;
+}
+
+void xz_dec_microlzma_end(struct xz_dec_microlzma *s)
+{
+	if (DEC_IS_MULTI(s->s.dict.mode))
+		vfree(s->s.dict.buf);
+
+	kfree(s);
+}
+#endif
diff --git a/modules/xz-embedded/src/xz_dec_stream.c b/modules/xz-embedded/src/xz_dec_stream.c
index d6525506a1..2c41f5f1b0 100644
--- a/modules/xz-embedded/src/xz_dec_stream.c
+++ b/modules/xz-embedded/src/xz_dec_stream.c
@@ -35,7 +35,8 @@ struct xz_dec {
 		SEQ_INDEX,
 		SEQ_INDEX_PADDING,
 		SEQ_INDEX_CRC32,
-		SEQ_STREAM_FOOTER
+		SEQ_STREAM_FOOTER,
+		SEQ_STREAM_PADDING
 	} sequence;
 
 	/* Position in variable-length integers and Check fields */
@@ -423,12 +424,12 @@ static enum xz_ret dec_stream_header(struct xz_dec *s)
 	 * check types too, but then the check won't be verified and
 	 * a warning (XZ_UNSUPPORTED_CHECK) will be given.
 	 */
+	if (s->temp.buf[HEADER_MAGIC_SIZE + 1] > XZ_CHECK_MAX)
+		return XZ_OPTIONS_ERROR;
+
 	s->check_type = s->temp.buf[HEADER_MAGIC_SIZE + 1];
 
 #ifdef XZ_DEC_ANY_CHECK
-	if (s->check_type > XZ_CHECK_MAX)
-		return XZ_OPTIONS_ERROR;
-
 	if (s->check_type > XZ_CHECK_CRC32 && !IS_CRC64(s->check_type))
 		return XZ_UNSUPPORTED_CHECK;
 #else
@@ -604,6 +605,8 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
 			if (ret != XZ_OK)
 				return ret;
 
+		/* Fall through */
+
 		case SEQ_BLOCK_START:
 			/* We need one byte of input to continue. */
 			if (b->in_pos == b->in_size)
@@ -627,6 +630,8 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
 			s->temp.pos = 0;
 			s->sequence = SEQ_BLOCK_HEADER;
 
+		/* Fall through */
+
 		case SEQ_BLOCK_HEADER:
 			if (!fill_temp(s, b))
 				return XZ_OK;
@@ -637,6 +642,8 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
 
 			s->sequence = SEQ_BLOCK_UNCOMPRESS;
 
+		/* Fall through */
+
 		case SEQ_BLOCK_UNCOMPRESS:
 			ret = dec_block(s, b);
 			if (ret != XZ_STREAM_END)
@@ -644,6 +651,8 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
 
 			s->sequence = SEQ_BLOCK_PADDING;
 
+		/* Fall through */
+
 		case SEQ_BLOCK_PADDING:
 			/*
 			 * Size of Compressed Data + Block Padding
@@ -664,6 +673,8 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
 
 			s->sequence = SEQ_BLOCK_CHECK;
 
+		/* Fall through */
+
 		case SEQ_BLOCK_CHECK:
 			if (s->check_type == XZ_CHECK_CRC32) {
 				ret = crc_validate(s, b, 32);
@@ -691,6 +702,8 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
 
 			s->sequence = SEQ_INDEX_PADDING;
 
+		/* Fall through */
+
 		case SEQ_INDEX_PADDING:
 			while ((s->index.size + (b->in_pos - s->in_start))
 					& 3) {
@@ -713,6 +726,8 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
 
 			s->sequence = SEQ_INDEX_CRC32;
 
+		/* Fall through */
+
 		case SEQ_INDEX_CRC32:
 			ret = crc_validate(s, b, 32);
 			if (ret != XZ_STREAM_END)
@@ -721,11 +736,17 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
 			s->temp.size = STREAM_HEADER_SIZE;
 			s->sequence = SEQ_STREAM_FOOTER;
 
+		/* Fall through */
+
 		case SEQ_STREAM_FOOTER:
 			if (!fill_temp(s, b))
 				return XZ_OK;
 
 			return dec_stream_footer(s);
+
+		case SEQ_STREAM_PADDING:
+			/* Never reached, only silencing a warning */
+			break;
 		}
 	}
 
@@ -793,6 +814,79 @@ XZ_EXTERN enum xz_ret xz_dec_run(struct xz_dec *s, struct xz_buf *b)
 	return ret;
 }
 
+#ifdef XZ_DEC_CONCATENATED
+XZ_EXTERN enum xz_ret xz_dec_catrun(struct xz_dec *s, struct xz_buf *b,
+				    int finish)
+{
+	enum xz_ret ret;
+
+	if (DEC_IS_SINGLE(s->mode)) {
+		xz_dec_reset(s);
+		finish = true;
+	}
+
+	while (true) {
+		if (s->sequence == SEQ_STREAM_PADDING) {
+			/*
+			 * Skip Stream Padding. Its size must be a multiple
+			 * of four bytes which is tracked with s->pos.
+			 */
+			while (true) {
+				if (b->in_pos == b->in_size) {
+					/*
+					 * Note that if we are repeatedly
+					 * given no input and finish is false,
+					 * we will keep returning XZ_OK even
+					 * though no progress is being made.
+					 * The lack of XZ_BUF_ERROR support
+					 * isn't a problem here because a
+					 * reasonable caller will eventually
+					 * provide more input or set finish
+					 * to true.
+					 */
+					if (!finish)
+						return XZ_OK;
+
+					if (s->pos != 0)
+						return XZ_DATA_ERROR;
+
+					return XZ_STREAM_END;
+				}
+
+				if (b->in[b->in_pos] != 0x00) {
+					if (s->pos != 0)
+						return XZ_DATA_ERROR;
+
+					break;
+				}
+
+				++b->in_pos;
+				s->pos = (s->pos + 1) & 3;
+			}
+
+			/*
+			 * More input remains. It should be a new Stream.
+			 *
+			 * In single-call mode xz_dec_run() will always call
+			 * xz_dec_reset(). Thus, we need to do it here only
+			 * in multi-call mode.
+			 */
+			if (DEC_IS_MULTI(s->mode))
+				xz_dec_reset(s);
+		}
+
+		ret = xz_dec_run(s, b);
+
+		if (ret != XZ_STREAM_END)
+			break;
+
+		s->sequence = SEQ_STREAM_PADDING;
+	}
+
+	return ret;
+}
+#endif
+
 XZ_EXTERN struct xz_dec *xz_dec_init(enum xz_mode mode, uint32_t dict_max)
 {
 	struct xz_dec *s = kmalloc(sizeof(*s), GFP_KERNEL);
diff --git a/modules/xz-embedded/src/xz_lzma2.h b/modules/xz-embedded/src/xz_lzma2.h
index 071d67bee9..92d852d4f8 100644
--- a/modules/xz-embedded/src/xz_lzma2.h
+++ b/modules/xz-embedded/src/xz_lzma2.h
@@ -2,7 +2,7 @@
  * LZMA2 definitions
  *
  * Authors: Lasse Collin <lasse.collin@tukaani.org>
- *          Igor Pavlov <http://7-zip.org/>
+ *          Igor Pavlov <https://7-zip.org/>
  *
  * This file has been put into the public domain.
  * You can do whatever you want with this file.
diff --git a/modules/xz-embedded/src/xz_private.h b/modules/xz-embedded/src/xz_private.h
index 482b90f363..d9fd49b45f 100644
--- a/modules/xz-embedded/src/xz_private.h
+++ b/modules/xz-embedded/src/xz_private.h
@@ -37,6 +37,9 @@
 #		ifdef CONFIG_XZ_DEC_SPARC
 #			define XZ_DEC_SPARC
 #		endif
+#		ifdef CONFIG_XZ_DEC_MICROLZMA
+#			define XZ_DEC_MICROLZMA
+#		endif
 #		define memeq(a, b, size) (memcmp(a, b, size) == 0)
 #		define memzero(buf, size) memset(buf, 0, size)
 #	endif
diff --git a/modules/xz-embedded/src/xz_stream.h b/modules/xz-embedded/src/xz_stream.h
index 66cb5a7055..430bb3a0d1 100644
--- a/modules/xz-embedded/src/xz_stream.h
+++ b/modules/xz-embedded/src/xz_stream.h
@@ -19,7 +19,7 @@
 
 /*
  * See the .xz file format specification at
- * http://tukaani.org/xz/xz-file-format.txt
+ * https://tukaani.org/xz/xz-file-format.txt
  * to understand the container format.
  */
 
diff --git a/modules/xz-embedded/update.sh b/modules/xz-embedded/update.sh
index ecc1e3610e..37280bba12 100755
--- a/modules/xz-embedded/update.sh
+++ b/modules/xz-embedded/update.sh
@@ -4,11 +4,12 @@
 
 MY_TEMP_DIR=$(mktemp -d -t xz-embedded_update.XXXXXX) || exit 1
 
-git clone http://git.tukaani.org/xz-embedded.git ${MY_TEMP_DIR}/xz-embedded
+git clone https://git.tukaani.org/xz-embedded.git ${MY_TEMP_DIR}/xz-embedded
 
 COMMIT=$(git -C ${MY_TEMP_DIR}/xz-embedded rev-parse HEAD)
 cd $(dirname $0)
-perl -p -i -e "s/\[commit [0-9a-f]{40}\]/[${COMMIT}]/" README.mozilla;
+perl -p -i -e "s/\[[0-9a-f]{40}\]/[${COMMIT}]/" README.mozilla;
+rm -f README.mozilla.bak;
 
 rm -rf src
 mkdir src
@@ -23,7 +24,6 @@ mv ${MY_TEMP_DIR}/xz-embedded/linux/lib/xz/xz_dec_bcj.c src/
 mv ${MY_TEMP_DIR}/xz-embedded/linux/lib/xz/xz_dec_stream.c src/
 mv ${MY_TEMP_DIR}/xz-embedded/linux/lib/xz/xz_dec_lzma2.c src/
 rm -rf ${MY_TEMP_DIR}
-hg addremove src
 
 echo "###"
 echo "### Updated xz-embedded/src to $COMMIT."