[PATCH v8 0/2] Introduce EROFS support

From: Yifan Zhao <zhaoyifan@sjtu.edu.cn>
To: grub-devel@gnu.org
Cc: dja@axtens.net, development@efficientek.com, dkiper@net-space.pl,
	hsiangkao@linux.alibaba.com, zhaoyifan@sjtu.edu.cn
Subject: [PATCH v8 0/2] Introduce EROFS support
Date: Wed, 24 Apr 2024 17:30:15 +0800	[thread overview]
Message-ID: <20240424093019.1865982-1-zhaoyifan@sjtu.edu.cn> (raw)

EROFS [1] is a lightweight read-only filesystem designed for performance
which has already been shipped in most Linux distributions as well as widely
used in several scenarios, such as Android system partitions, container
images, and rootfs for embedded devices.

This patch brings EROFS uncompressed support together with related tests.
Now, it's possible to boot directly through GRUB with an EROFS rootfs.

EROFS compressed files will be supported later since it has more work to
polish.

[1] https://erofs.docs.kernel.org

changelog since v7:
- check if log2_blksz is too small in erofs_mount()
- handle bondary case and memleak in erofs_iterate_dir()
- fix incorrect grub_strnlen() implementation

Yifan Zhao (2):
  fs/erofs: Add support for EROFS
  fs/erofs: Add tests for EROFS in grub-fs-tester

 .gitignore                   |   1 +
 INSTALL                      |   8 +-
 Makefile.util.def            |   7 +
 docs/grub.texi               |   3 +-
 grub-core/Makefile.core.def  |   5 +
 grub-core/fs/erofs.c         | 984 +++++++++++++++++++++++++++++++++++
 grub-core/kern/misc.c        |  14 +
 include/grub/misc.h          |   1 +
 tests/erofs_test.in          |  20 +
 tests/util/grub-fs-tester.in |  32 +-
 10 files changed, 1063 insertions(+), 12 deletions(-)
 create mode 100644 grub-core/fs/erofs.c
 create mode 100644 tests/erofs_test.in

Interdiff against v7:

diff --git a/grub-core/fs/erofs.c b/grub-core/fs/erofs.c
index 5b89b7924..13f92e71a 100644
--- a/grub-core/fs/erofs.c
+++ b/grub-core/fs/erofs.c
@@ -101,6 +101,7 @@ struct grub_erofs_inode_chunk_info
 
 #define EROFS_NULL_ADDR			1
 #define EROFS_NAME_LEN			255
+#define EROFS_MIN_LOG2_BLOCK_SIZE	9
 #define EROFS_MAX_LOG2_BLOCK_SIZE	16
 
 struct grub_erofs_inode_chunk_index
@@ -558,7 +559,7 @@ erofs_iterate_dir (grub_fshelp_node_t dir, grub_fshelp_iterate_dir_hook_t hook,
 	goto not_found;
 
       nameoff = grub_le_to_cpu16 (de->nameoff);
-      if (nameoff < sizeof (struct grub_erofs_dirent) || nameoff > maxsize)
+      if (nameoff < sizeof (struct grub_erofs_dirent) || nameoff >= maxsize)
 	{
 	  grub_error (GRUB_ERR_BAD_FS,
 		      "invalid nameoff %u @ inode %" PRIuGRUB_UINT64_T,
@@ -587,11 +588,12 @@ erofs_iterate_dir (grub_fshelp_node_t dir, grub_fshelp_iterate_dir_hook_t hook,
 	  fdiro->inode_loaded = false;
 
 	  nameoff = grub_le_to_cpu16 (de->nameoff);
-	  if (nameoff < sizeof (struct grub_erofs_dirent) || nameoff > maxsize)
+	  if (nameoff < sizeof (struct grub_erofs_dirent) || nameoff >= maxsize)
 	    {
 	      grub_error (GRUB_ERR_BAD_FS,
 			  "invalid nameoff %u @ inode %" PRIuGRUB_UINT64_T,
 			  nameoff, dir->ino);
+	      grub_free (fdiro);
 	      goto not_found;
 	    }
 
@@ -607,6 +609,7 @@ erofs_iterate_dir (grub_fshelp_node_t dir, grub_fshelp_iterate_dir_hook_t hook,
 			  "invalid de_namelen %" PRIuGRUB_SIZE
 			  " @ inode %" PRIuGRUB_UINT64_T,
 			  de_namelen, dir->ino);
+	      grub_free (fdiro);
 	      goto not_found;
 	    }
 
@@ -700,6 +703,7 @@ erofs_mount (grub_disk_t disk, bool read_root)
   if (err != GRUB_ERR_NONE)
     return NULL;
   if (sb.magic != grub_cpu_to_le32_compile_time (EROFS_MAGIC) ||
+      grub_le_to_cpu32 (sb.log2_blksz) < EROFS_MIN_LOG2_BLOCK_SIZE ||
       grub_le_to_cpu32 (sb.log2_blksz) > EROFS_MAX_LOG2_BLOCK_SIZE)
     {
       grub_error (GRUB_ERR_BAD_FS, "not a valid erofs filesystem");
diff --git a/grub-core/kern/misc.c b/grub-core/kern/misc.c
index ecb27fa5a..67240d64d 100644
--- a/grub-core/kern/misc.c
+++ b/grub-core/kern/misc.c
@@ -602,7 +602,7 @@ grub_strnlen (const char *s, grub_size_t n)
   if (n == 0)
     return 0;
 
-  while (*p && n--)
+  while (n-- && *p)
     p++;
 
   return p - s;
-- 
2.44.0


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