[PATCH for-4.19 1/2] staging: erofs: fix error handling when failed to read compresssed data

[PATCH for-4.19 1/2] staging: erofs: fix error handling when failed to read compresssed data

[Gao Xiang]

commit b6391ac73400eff38377a4a7364bd3df5efb5178 upstream.

Complete read error handling paths for all three kinds of
compressed pages:

 1) For cache-managed pages, PG_uptodate will be checked since
    read_endio will unlock and SetPageUptodate for these pages;

 2) For inplaced pages, read_endio cannot SetPageUptodate directly
    since it should be used to mark the final decompressed data,
    PG_error will be set with page locked for IO error instead;

 3) For staging pages, PG_error is used, which is similar to
    what we do for inplaced pages.

Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support")
Cc: <stable at vger.kernel.org> # 4.19+
Reviewed-by: Chao Yu <yuchao0 at huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25 at huawei.com>
---
This series resolves the following conflicts:
FAILED: patch "[PATCH] staging: erofs: fix error handling when failed to read" failed to apply to 4.19-stable tree
FAILED: patch "[PATCH] staging: erofs: keep corrupted fs from crashing kernel in" failed to apply to 4.19-stable tree

Thanks,
Gao Xiang

 drivers/staging/erofs/unzip_vle.c | 42 +++++++++++++++++++++----------
 1 file changed, 29 insertions(+), 13 deletions(-)

diff --git a/drivers/staging/erofs/unzip_vle.c b/drivers/staging/erofs/unzip_vle.c
index f44662dd795c..bb9a69158ba4 100644
--- a/drivers/staging/erofs/unzip_vle.c
+++ b/drivers/staging/erofs/unzip_vle.c
@@ -885,6 +885,7 @@ static int z_erofs_vle_unzip(struct super_block *sb,
 	overlapped = false;
 	compressed_pages = grp->compressed_pages;
 
+	err = 0;
 	for (i = 0; i < clusterpages; ++i) {
 		unsigned pagenr;
 
@@ -894,26 +895,39 @@ static int z_erofs_vle_unzip(struct super_block *sb,
 		DBG_BUGON(page == NULL);
 		DBG_BUGON(page->mapping == NULL);
 
-		if (z_erofs_is_stagingpage(page))
-			continue;
+		if (!z_erofs_is_stagingpage(page)) {
 #ifdef EROFS_FS_HAS_MANAGED_CACHE
-		if (page->mapping == mngda) {
-			DBG_BUGON(!PageUptodate(page));
-			continue;
-		}
+			if (page->mapping == mngda) {
+				if (unlikely(!PageUptodate(page)))
+					err = -EIO;
+				continue;
+			}
 #endif
 
-		/* only non-head page could be reused as a compressed page */
-		pagenr = z_erofs_onlinepage_index(page);
+			/*
+			 * only if non-head page can be selected
+			 * for inplace decompression
+			 */
+			pagenr = z_erofs_onlinepage_index(page);
 
-		DBG_BUGON(pagenr >= nr_pages);
-		DBG_BUGON(pages[pagenr]);
-		++sparsemem_pages;
-		pages[pagenr] = page;
+			DBG_BUGON(pagenr >= nr_pages);
+			DBG_BUGON(pages[pagenr]);
+			++sparsemem_pages;
+			pages[pagenr] = page;
 
-		overlapped = true;
+			overlapped = true;
+		}
+
+		/* PG_error needs checking for inplaced and staging pages */
+		if (unlikely(PageError(page))) {
+			DBG_BUGON(PageUptodate(page));
+			err = -EIO;
+		}
 	}
 
+	if (unlikely(err))
+		goto out;
+
 	llen = (nr_pages << PAGE_SHIFT) - work->pageofs;
 
 	if (z_erofs_vle_workgrp_fmt(grp) == Z_EROFS_VLE_WORKGRP_FMT_PLAIN) {
@@ -1078,6 +1092,8 @@ static inline bool recover_managed_page(struct z_erofs_vle_workgroup *grp,
 		return true;
 
 	lock_page(page);
+	ClearPageError(page);
+
 	if (unlikely(!PagePrivate(page))) {
 		set_page_private(page, (unsigned long)grp);
 		SetPagePrivate(page);
-- 
2.17.1

[PATCH for-4.19 2/2] staging: erofs: keep corrupted fs from crashing kernel in erofs_readdir()

[Gao Xiang]

commit 33bac912840fe64dbc15556302537dc6a17cac63 upstream.

After commit 419d6efc50e9, kernel cannot be crashed in the namei
path. However, corrupted nameoff can do harm in the process of
readdir for scenerios without dm-verity as well. Fix it now.

Fixes: 3aa8ec716e52 ("staging: erofs: add directory operations")
Cc: <stable at vger.kernel.org> # 4.19+
Reviewed-by: Chao Yu <yuchao0 at huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25 at huawei.com>
---
 drivers/staging/erofs/dir.c | 45 ++++++++++++++++++++-----------------
 1 file changed, 25 insertions(+), 20 deletions(-)

diff --git a/drivers/staging/erofs/dir.c b/drivers/staging/erofs/dir.c
index 04b84ff31d03..0a089cf5c78f 100644
--- a/drivers/staging/erofs/dir.c
+++ b/drivers/staging/erofs/dir.c
@@ -23,6 +23,21 @@ static const unsigned char erofs_filetype_table[EROFS_FT_MAX] = {
 	[EROFS_FT_SYMLINK]	= DT_LNK,
 };
 
+static void debug_one_dentry(unsigned char d_type, const char *de_name,
+			     unsigned int de_namelen)
+{
+#ifdef CONFIG_EROFS_FS_DEBUG
+	/* since the on-disk name could not have the trailing '\0' */
+	unsigned char dbg_namebuf[EROFS_NAME_LEN + 1];
+
+	memcpy(dbg_namebuf, de_name, de_namelen);
+	dbg_namebuf[de_namelen] = '\0';
+
+	debugln("found dirent %s de_len %u d_type %d", dbg_namebuf,
+		de_namelen, d_type);
+#endif
+}
+
 static int erofs_fill_dentries(struct dir_context *ctx,
 	void *dentry_blk, unsigned *ofs,
 	unsigned nameoff, unsigned maxsize)
@@ -33,14 +48,10 @@ static int erofs_fill_dentries(struct dir_context *ctx,
 	de = dentry_blk + *ofs;
 	while (de < end) {
 		const char *de_name;
-		int de_namelen;
+		unsigned int de_namelen;
 		unsigned char d_type;
-#ifdef CONFIG_EROFS_FS_DEBUG
-		unsigned dbg_namelen;
-		unsigned char dbg_namebuf[EROFS_NAME_LEN];
-#endif
 
-		if (unlikely(de->file_type < EROFS_FT_MAX))
+		if (de->file_type < EROFS_FT_MAX)
 			d_type = erofs_filetype_table[de->file_type];
 		else
 			d_type = DT_UNKNOWN;
@@ -48,26 +59,20 @@ static int erofs_fill_dentries(struct dir_context *ctx,
 		nameoff = le16_to_cpu(de->nameoff);
 		de_name = (char *)dentry_blk + nameoff;
 
-		de_namelen = unlikely(de + 1 >= end) ?
-			/* last directory entry */
-			strnlen(de_name, maxsize - nameoff) :
-			le16_to_cpu(de[1].nameoff) - nameoff;
+		/* the last dirent in the block? */
+		if (de + 1 >= end)
+			de_namelen = strnlen(de_name, maxsize - nameoff);
+		else
+			de_namelen = le16_to_cpu(de[1].nameoff) - nameoff;
 
 		/* a corrupted entry is found */
-		if (unlikely(de_namelen < 0)) {
+		if (unlikely(nameoff + de_namelen > maxsize ||
+			     de_namelen > EROFS_NAME_LEN)) {
 			DBG_BUGON(1);
 			return -EIO;
 		}
 
-#ifdef CONFIG_EROFS_FS_DEBUG
-		dbg_namelen = min(EROFS_NAME_LEN - 1, de_namelen);
-		memcpy(dbg_namebuf, de_name, dbg_namelen);
-		dbg_namebuf[dbg_namelen] = '\0';
-
-		debugln("%s, found de_name %s de_len %d d_type %d", __func__,
-			dbg_namebuf, de_namelen, d_type);
-#endif
-
+		debug_one_dentry(d_type, de_name, de_namelen);
 		if (!dir_emit(ctx, de_name, de_namelen,
 					le64_to_cpu(de->nid), d_type))
 			/* stoped by some reason */
-- 
2.17.1

[PATCH for-4.19 1/2] staging: erofs: fix error handling when failed to read compresssed data

[Greg Kroah-Hartman]

On Mon, Apr 01, 2019@02:53:08PM +0800, Gao Xiang wrote:
> commit b6391ac73400eff38377a4a7364bd3df5efb5178 upstream.
> 
> Complete read error handling paths for all three kinds of
> compressed pages:
> 
>  1) For cache-managed pages, PG_uptodate will be checked since
>     read_endio will unlock and SetPageUptodate for these pages;
> 
>  2) For inplaced pages, read_endio cannot SetPageUptodate directly
>     since it should be used to mark the final decompressed data,
>     PG_error will be set with page locked for IO error instead;
> 
>  3) For staging pages, PG_error is used, which is similar to
>     what we do for inplaced pages.
> 
> Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support")
> Cc: <stable at vger.kernel.org> # 4.19+
> Reviewed-by: Chao Yu <yuchao0 at huawei.com>
> Signed-off-by: Gao Xiang <gaoxiang25 at huawei.com>
> ---
> This series resolves the following conflicts:
> FAILED: patch "[PATCH] staging: erofs: fix error handling when failed to read" failed to apply to 4.19-stable tree
> FAILED: patch "[PATCH] staging: erofs: keep corrupted fs from crashing kernel in" failed to apply to 4.19-stable tree

Thanks for both of these, now queued up.

greg k-h

[PATCH for-4.19 1/2] staging: erofs: fix error handling when failed to read compresssed data

[Gao Xiang]

On 2019/4/1 19:40, Greg Kroah-Hartman wrote:
> On Mon, Apr 01, 2019@02:53:08PM +0800, Gao Xiang wrote:
>> commit b6391ac73400eff38377a4a7364bd3df5efb5178 upstream.
>>
>> Complete read error handling paths for all three kinds of
>> compressed pages:
>>
>>  1) For cache-managed pages, PG_uptodate will be checked since
>>     read_endio will unlock and SetPageUptodate for these pages;
>>
>>  2) For inplaced pages, read_endio cannot SetPageUptodate directly
>>     since it should be used to mark the final decompressed data,
>>     PG_error will be set with page locked for IO error instead;
>>
>>  3) For staging pages, PG_error is used, which is similar to
>>     what we do for inplaced pages.
>>
>> Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support")
>> Cc: <stable at vger.kernel.org> # 4.19+
>> Reviewed-by: Chao Yu <yuchao0 at huawei.com>
>> Signed-off-by: Gao Xiang <gaoxiang25 at huawei.com>
>> ---
>> This series resolves the following conflicts:
>> FAILED: patch "[PATCH] staging: erofs: fix error handling when failed to read" failed to apply to 4.19-stable tree
>> FAILED: patch "[PATCH] staging: erofs: keep corrupted fs from crashing kernel in" failed to apply to 4.19-stable tree
> 
> Thanks for both of these, now queued up.
> 
> greg k-h

It's my pleasure to backport related conflict bugfixes to stable kernels. :)

Thanks,
Gao Xiang


>