kernel: backport fix for recently introduced UBI bug

Import commit "ubi: Fix failure attaching when vid_hdr offset equals to
(sub)page size" which did not yet make it to stable upstream Linux trees.

Fixes: #12232
Fixes: #12339
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
(cherry picked from commit aad34818b50029e07ed9221ae46f9770d6e29785)

2 files changed, 71 insertions, 2 deletions

diff --git a/target/linux/generic/backport-5.4/430-v6.3-ubi-Fix-failure-attaching-when-vid_hdr-offset-equals.patch b/target/linux/generic/backport-5.4/430-v6.3-ubi-Fix-failure-attaching-when-vid_hdr-offset-equals.patch
new file mode 100644
index 0000000000..afb8e5ee14
--- /dev/null
+++ b/target/linux/generic/backport-5.4/430-v6.3-ubi-Fix-failure-attaching-when-vid_hdr-offset-equals.patch
@@ -0,0 +1,69 @@
+From 1e020e1b96afdecd20680b5b5be2a6ffc3d27628 Mon Sep 17 00:00:00 2001
+From: Zhihao Cheng <chengzhihao1@huawei.com>
+Date: Mon, 6 Mar 2023 09:33:08 +0800
+Subject: [PATCH] ubi: Fix failure attaching when vid_hdr offset equals to
+ (sub)page size
+
+Following process will make ubi attaching failed since commit
+1b42b1a36fc946 ("ubi: ensure that VID header offset ... size"):
+
+ID="0xec,0xa1,0x00,0x15" # 128M 128KB 2KB
+modprobe nandsim id_bytes=$ID
+flash_eraseall /dev/mtd0
+modprobe ubi mtd="0,2048"  # set vid_hdr offset as 2048 (one page)
+(dmesg):
+  ubi0 error: ubi_attach_mtd_dev [ubi]: VID header offset 2048 too large.
+  UBI error: cannot attach mtd0
+  UBI error: cannot initialize UBI, error -22
+
+Rework original solution, the key point is making sure
+'vid_hdr_shift + UBI_VID_HDR_SIZE < ubi->vid_hdr_alsize',
+so we should check vid_hdr_shift rather not vid_hdr_offset.
+Then, ubi still support (sub)page aligined VID header offset.
+
+Fixes: 1b42b1a36fc946 ("ubi: ensure that VID header offset ... size")
+Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
+Tested-by: Nicolas Schichan <nschichan@freebox.fr>
+Tested-by: Miquel Raynal <miquel.raynal@bootlin.com> # v5.10, v4.19
+Signed-off-by: Richard Weinberger <richard@nod.at>
+---
+ drivers/mtd/ubi/build.c | 21 +++++++++++++++------
+ 1 file changed, 15 insertions(+), 6 deletions(-)
+
+--- a/drivers/mtd/ubi/build.c
++++ b/drivers/mtd/ubi/build.c
+@@ -644,12 +644,6 @@ static int io_init(struct ubi_device *ub
+ 	ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
+ 	ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
+ 
+-	if (ubi->vid_hdr_offset && ((ubi->vid_hdr_offset + UBI_VID_HDR_SIZE) >
+-	    ubi->vid_hdr_alsize)) {
+-		ubi_err(ubi, "VID header offset %d too large.", ubi->vid_hdr_offset);
+-		return -EINVAL;
+-	}
+-
+ 	dbg_gen("min_io_size      %d", ubi->min_io_size);
+ 	dbg_gen("max_write_size   %d", ubi->max_write_size);
+ 	dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
+@@ -667,6 +661,21 @@ static int io_init(struct ubi_device *ub
+ 						ubi->vid_hdr_aloffset;
+ 	}
+ 
++	/*
++	 * Memory allocation for VID header is ubi->vid_hdr_alsize
++	 * which is described in comments in io.c.
++	 * Make sure VID header shift + UBI_VID_HDR_SIZE not exceeds
++	 * ubi->vid_hdr_alsize, so that all vid header operations
++	 * won't access memory out of bounds.
++	 */
++	if ((ubi->vid_hdr_shift + UBI_VID_HDR_SIZE) > ubi->vid_hdr_alsize) {
++		ubi_err(ubi, "Invalid VID header offset %d, VID header shift(%d)"
++			" + VID header size(%zu) > VID header aligned size(%d).",
++			ubi->vid_hdr_offset, ubi->vid_hdr_shift,
++			UBI_VID_HDR_SIZE, ubi->vid_hdr_alsize);
++		return -EINVAL;
++	}
++
+ 	/* Similar for the data offset */
+ 	ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
+ 	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
diff --git a/target/linux/generic/pending-5.4/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch b/target/linux/generic/pending-5.4/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch
index b21daea4f0..cc19a5e628 100644
--- a/target/linux/generic/pending-5.4/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch
+++ b/target/linux/generic/pending-5.4/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch
@@ -8,7 +8,7 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
 
 --- a/drivers/mtd/ubi/build.c
 +++ b/drivers/mtd/ubi/build.c
-@@ -1168,6 +1168,73 @@ static struct mtd_info * __init open_mtd
+@@ -1177,6 +1177,73 @@ static struct mtd_info * __init open_mtd
  	return mtd;
  }
  
@@ -82,7 +82,7 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
  static int __init ubi_init(void)
  {
  	int err, i, k;
-@@ -1251,6 +1318,12 @@ static int __init ubi_init(void)
+@@ -1260,6 +1327,12 @@ static int __init ubi_init(void)
  		}
  	}