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authorHauke Mehrtens <hauke@hauke-m.de>2018-11-01 17:57:55 +0100
committerHauke Mehrtens <hauke@hauke-m.de>2018-12-15 12:50:06 +0100
commit52a82ce3dd901a1536c7d7d9d963e9c2d761c816 (patch)
tree79020fb59420fcea7bdc4b12272f7251e101fe64 /target/linux/generic/backport-4.19/043-v4.18-mtd-bcm47xxpart-improve-handling-TRX-partition-size.patch
parenta272af75cd8c67d265400f96c1e6bb172315c23c (diff)
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kernel: Copy patches from kernel 4.14 to 4.19
This just copies the files from the kernel 4.14 specific folders into the kernel 4.19 specific folder, no changes are done to the files in this commit. Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Diffstat (limited to 'target/linux/generic/backport-4.19/043-v4.18-mtd-bcm47xxpart-improve-handling-TRX-partition-size.patch')
-rw-r--r--target/linux/generic/backport-4.19/043-v4.18-mtd-bcm47xxpart-improve-handling-TRX-partition-size.patch70
1 files changed, 70 insertions, 0 deletions
diff --git a/target/linux/generic/backport-4.19/043-v4.18-mtd-bcm47xxpart-improve-handling-TRX-partition-size.patch b/target/linux/generic/backport-4.19/043-v4.18-mtd-bcm47xxpart-improve-handling-TRX-partition-size.patch
new file mode 100644
index 0000000000..e08f8dad32
--- /dev/null
+++ b/target/linux/generic/backport-4.19/043-v4.18-mtd-bcm47xxpart-improve-handling-TRX-partition-size.patch
@@ -0,0 +1,70 @@
+From 237ea0d4762cc14d0fc80e80d61f0f08e1050c7f Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Thu, 12 Apr 2018 07:24:52 +0200
+Subject: [PATCH] mtd: bcm47xxpart: improve handling TRX partition size
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+When bcm47xxpart finds a TRX partition (container) it's supposed to jump
+to the end of it and keep looking for more partitions. TRX and its
+subpartitions are handled by a separate parser.
+
+The problem with old code was relying on the length specified in a TRX
+header. That isn't reliable as TRX is commonly modified to have checksum
+cover only non-changing subpartitions. Otherwise modifying e.g. a rootfs
+would result in CRC32 mismatch and bootloader refusing to boot a
+firmware.
+
+Fix it by trying better to figure out a real TRX size. We can securely
+assume that TRX has to cover all subpartitions and the last one is at
+least of a block size in size. Then compare it with a length field.
+
+This makes code more optimal & reliable thanks to skipping data that
+shouldn't be parsed.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
+---
+ drivers/mtd/bcm47xxpart.c | 22 ++++++++++++++++++----
+ 1 file changed, 18 insertions(+), 4 deletions(-)
+
+--- a/drivers/mtd/bcm47xxpart.c
++++ b/drivers/mtd/bcm47xxpart.c
+@@ -186,6 +186,8 @@ static int bcm47xxpart_parse(struct mtd_
+ /* TRX */
+ if (buf[0x000 / 4] == TRX_MAGIC) {
+ struct trx_header *trx;
++ uint32_t last_subpart;
++ uint32_t trx_size;
+
+ if (trx_num >= ARRAY_SIZE(trx_parts))
+ pr_warn("No enough space to store another TRX found at 0x%X\n",
+@@ -195,11 +197,23 @@ static int bcm47xxpart_parse(struct mtd_
+ bcm47xxpart_add_part(&parts[curr_part++], "firmware",
+ offset, 0);
+
+- /* Jump to the end of TRX */
++ /*
++ * Try to find TRX size. The "length" field isn't fully
++ * reliable as it could be decreased to make CRC32 cover
++ * only part of TRX data. It's commonly used as checksum
++ * can't cover e.g. ever-changing rootfs partition.
++ * Use offsets as helpers for assuming min TRX size.
++ */
+ trx = (struct trx_header *)buf;
+- offset = roundup(offset + trx->length, blocksize);
+- /* Next loop iteration will increase the offset */
+- offset -= blocksize;
++ last_subpart = max3(trx->offset[0], trx->offset[1],
++ trx->offset[2]);
++ trx_size = max(trx->length, last_subpart + blocksize);
++
++ /*
++ * Skip the TRX data. Decrease offset by block size as
++ * the next loop iteration will increase it.
++ */
++ offset += roundup(trx_size, blocksize) - blocksize;
+ continue;
+ }
+