Merge tag 'pstore-v6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore updates from Kees Cook:

 - Greatly simplify compression support (Ard Biesheuvel)

 - Avoid crashes for corrupted offsets when prz size is 0 (Enlin Mu)

 - Expand range of usable record sizes (Yuxiao Zhang)

 - Fix kernel-doc warning (Matthew Wilcox)

* tag 'pstore-v6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  pstore: Fix kernel-doc warning
  pstore: Support record sizes larger than kmalloc() limit
  pstore/ram: Check start of empty przs during init
  pstore: Replace crypto API compression with zlib_deflate library calls
  pstore: Remove worst-case compression size logic

fs/pstore/Kconfig

 # SPDX-License-Identifier: GPL-2.0-only
 config PSTORE
 	tristate "Persistent store support"
-	select CRYPTO if PSTORE_COMPRESS
 	default n
 	help
 	   This option enables generic access to platform level
@@ -22,99 +21,18 @@ config PSTORE_DEFAULT_KMSG_BYTES
 	  Defines default size of pstore kernel log storage.
 	  Can be enlarged if needed, not recommended to shrink it.
 
-config PSTORE_DEFLATE_COMPRESS
-	tristate "DEFLATE (ZLIB) compression"
-	default y
-	depends on PSTORE
-	select CRYPTO_DEFLATE
-	help
-	  This option enables DEFLATE (also known as ZLIB) compression
-	  algorithm support.
-
-config PSTORE_LZO_COMPRESS
-	tristate "LZO compression"
-	depends on PSTORE
-	select CRYPTO_LZO
-	help
-	  This option enables LZO compression algorithm support.
-
-config PSTORE_LZ4_COMPRESS
-	tristate "LZ4 compression"
-	depends on PSTORE
-	select CRYPTO_LZ4
-	help
-	  This option enables LZ4 compression algorithm support.
-
-config PSTORE_LZ4HC_COMPRESS
-	tristate "LZ4HC compression"
-	depends on PSTORE
-	select CRYPTO_LZ4HC
-	help
-	  This option enables LZ4HC (high compression) mode algorithm.
-
-config PSTORE_842_COMPRESS
-	bool "842 compression"
-	depends on PSTORE
-	select CRYPTO_842
-	help
-	  This option enables 842 compression algorithm support.
-
-config PSTORE_ZSTD_COMPRESS
-	bool "zstd compression"
-	depends on PSTORE
-	select CRYPTO_ZSTD
-	help
-	  This option enables zstd compression algorithm support.
-
 config PSTORE_COMPRESS
-	def_bool y
+	bool "Pstore compression (deflate)"
 	depends on PSTORE
-	depends on PSTORE_DEFLATE_COMPRESS || PSTORE_LZO_COMPRESS ||	\
-		   PSTORE_LZ4_COMPRESS || PSTORE_LZ4HC_COMPRESS ||	\
-		   PSTORE_842_COMPRESS || PSTORE_ZSTD_COMPRESS
-
-choice
-	prompt "Default pstore compression algorithm"
-	depends on PSTORE_COMPRESS
+	select ZLIB_INFLATE
+	select ZLIB_DEFLATE
+	default y
 	help
-	  This option chooses the default active compression algorithm.
-	  This change be changed at boot with "pstore.compress=..." on
-	  the kernel command line.
-
-	  Currently, pstore has support for 6 compression algorithms:
-	  deflate, lzo, lz4, lz4hc, 842 and zstd.
-
-	  The default compression algorithm is deflate.
-
-	config PSTORE_DEFLATE_COMPRESS_DEFAULT
-		bool "deflate" if PSTORE_DEFLATE_COMPRESS
-
-	config PSTORE_LZO_COMPRESS_DEFAULT
-		bool "lzo" if PSTORE_LZO_COMPRESS
-
-	config PSTORE_LZ4_COMPRESS_DEFAULT
-		bool "lz4" if PSTORE_LZ4_COMPRESS
-
-	config PSTORE_LZ4HC_COMPRESS_DEFAULT
-		bool "lz4hc" if PSTORE_LZ4HC_COMPRESS
-
-	config PSTORE_842_COMPRESS_DEFAULT
-		bool "842" if PSTORE_842_COMPRESS
-
-	config PSTORE_ZSTD_COMPRESS_DEFAULT
-		bool "zstd" if PSTORE_ZSTD_COMPRESS
-
-endchoice
-
-config PSTORE_COMPRESS_DEFAULT
-	string
-	depends on PSTORE_COMPRESS
-	default "deflate" if PSTORE_DEFLATE_COMPRESS_DEFAULT
-	default "lzo" if PSTORE_LZO_COMPRESS_DEFAULT
-	default "lz4" if PSTORE_LZ4_COMPRESS_DEFAULT
-	default "lz4hc" if PSTORE_LZ4HC_COMPRESS_DEFAULT
-	default "842" if PSTORE_842_COMPRESS_DEFAULT
-	default "zstd" if PSTORE_ZSTD_COMPRESS_DEFAULT
+	  Whether pstore records should be compressed before being written to
+	  the backing store. This is implemented using the zlib 'deflate'
+	  algorithm, using the library implementation instead of using the full
+	  blown crypto API. This reduces the risk of secondary oopses or other
+	  problems while pstore is recording panic metadata.
 
 config PSTORE_CONSOLE
 	bool "Log kernel console messages"

fs/pstore/inode.c

@@ -54,7 +54,7 @@ static void free_pstore_private(struct pstore_private *private)
 	if (!private)
 		return;
 	if (private->record) {
-		kfree(private->record->buf);
+		kvfree(private->record->buf);
 		kfree(private->record->priv);
 		kfree(private->record);
 	}

fs/pstore/ram.c

@@ -20,6 +20,7 @@
 #include <linux/compiler.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
+#include <linux/mm.h>
 
 #include "internal.h"
 #include "ram_internal.h"
@@ -268,7 +269,7 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record)
 	/* ECC correction notice */
 	record->ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
 
-	record->buf = kmalloc(size + record->ecc_notice_size + 1, GFP_KERNEL);
+	record->buf = kvzalloc(size + record->ecc_notice_size + 1, GFP_KERNEL);
 	if (record->buf == NULL) {
 		size = -ENOMEM;
 		goto out;
@@ -282,7 +283,7 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record)
 
 out:
 	if (free_prz) {
-		kfree(prz->old_log);
+		kvfree(prz->old_log);
 		kfree(prz);
 	}
 
@@ -833,7 +834,7 @@ static int ramoops_probe(struct platform_device *pdev)
 	 */
 	if (cxt->pstore.flags & PSTORE_FLAGS_DMESG) {
 		cxt->pstore.bufsize = cxt->dprzs[0]->buffer_size;
-		cxt->pstore.buf = kzalloc(cxt->pstore.bufsize, GFP_KERNEL);
+		cxt->pstore.buf = kvzalloc(cxt->pstore.bufsize, GFP_KERNEL);
 		if (!cxt->pstore.buf) {
 			pr_err("cannot allocate pstore crash dump buffer\n");
 			err = -ENOMEM;
@@ -866,7 +867,7 @@ static int ramoops_probe(struct platform_device *pdev)
 	return 0;
 
 fail_buf:
-	kfree(cxt->pstore.buf);
+	kvfree(cxt->pstore.buf);
 fail_clear:
 	cxt->pstore.bufsize = 0;
 fail_init:
@@ -881,7 +882,7 @@ static void ramoops_remove(struct platform_device *pdev)
 
 	pstore_unregister(&cxt->pstore);
 
-	kfree(cxt->pstore.buf);
+	kvfree(cxt->pstore.buf);
 	cxt->pstore.bufsize = 0;
 
 	ramoops_free_przs(cxt);

fs/pstore/ram_core.c

@@ -17,6 +17,7 @@
 #include <linux/slab.h>
 #include <linux/uaccess.h>
 #include <linux/vmalloc.h>
+#include <linux/mm.h>
 #include <asm/page.h>
 
 #include "ram_internal.h"
@@ -24,12 +25,10 @@
 /**
  * struct persistent_ram_buffer - persistent circular RAM buffer
  *
- * @sig:
- *	signature to indicate header (PERSISTENT_RAM_SIG xor PRZ-type value)
- * @start:
- *	offset into @data where the beginning of the stored bytes begin
- * @size:
- *	number of valid bytes stored in @data
+ * @sig: Signature to indicate header (PERSISTENT_RAM_SIG xor PRZ-type value)
+ * @start: First valid byte in the buffer.
+ * @size: Number of valid bytes in the buffer.
+ * @data: The contents of the buffer.
  */
 struct persistent_ram_buffer {
 	uint32_t    sig;
@@ -301,7 +300,7 @@ void persistent_ram_save_old(struct persistent_ram_zone *prz)
 
 	if (!prz->old_log) {
 		persistent_ram_ecc_old(prz);
-		prz->old_log = kmalloc(size, GFP_KERNEL);
+		prz->old_log = kvzalloc(size, GFP_KERNEL);
 	}
 	if (!prz->old_log) {
 		pr_err("failed to allocate buffer\n");
@@ -385,7 +384,7 @@ void *persistent_ram_old(struct persistent_ram_zone *prz)
 
 void persistent_ram_free_old(struct persistent_ram_zone *prz)
 {
-	kfree(prz->old_log);
+	kvfree(prz->old_log);
 	prz->old_log = NULL;
 	prz->old_log_size = 0;
 }
@@ -519,7 +518,7 @@ static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
 	sig ^= PERSISTENT_RAM_SIG;
 
 	if (prz->buffer->sig == sig) {
-		if (buffer_size(prz) == 0) {
+		if (buffer_size(prz) == 0 && buffer_start(prz) == 0) {
 			pr_debug("found existing empty buffer\n");
 			return 0;
 		}