[PATCH 4.14 227/242] mtd: parser: cmdline: Fix parsing of part-names with colons

Greg Kroah-Hartman
2020-12-28T16:14:47Z

From: Sven Eckelmann <sven@narfation.org>

commit 639a82434f16a6df0ce0e7c8595976f1293940fd upstream.

Some devices (especially QCA ones) are already using hardcoded partition
names with colons in it. The OpenMesh A62 for example provides following
mtd relevant information via cmdline:

root=31:11 mtdparts=spi0.0:256k(0:SBL1),128k(0:MIBIB),384k(0:QSEE),64k(0:CDT),64k(0:DDRPARAMS),64k(0:APPSBLENV),512k(0:APPSBL),64k(0:ART),64k(custom),64k(0:KEYS),0x002b0000(kernel),0x00c80000(rootfs),15552k(inactive) rootfsname=rootfs rootwait

The change to split only on the last colon between mtd-id and partitions
will cause newpart to see following string for the first partition:

KEYS),0x002b0000(kernel),0x00c80000(rootfs),15552k(inactive)

Such a partition list cannot be parsed and thus the device fails to boot.

Avoid this behavior by making sure that the start of the first part-name
("(") will also be the last byte the mtd-id split algorithm is using for
its colon search.

Fixes: eb13fa022741 ("mtd: parser: cmdline: Support MTD names containing one or more colons")
Cc: stable@vger.kernel.org
Cc: Ron Minnich <rminnich@google.com>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20201124062506.185392-1-sven@narfation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/mtd/cmdlinepart.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)

--- a/drivers/mtd/cmdlinepart.c
+++ b/drivers/mtd/cmdlinepart.c
@@ -228,7 +228,7 @@ static int mtdpart_setup_real(char *s)
struct cmdline_mtd_partition *this_mtd;
struct mtd_partition *parts;
int mtd_id_len, num_parts;
- char *p, *mtd_id, *semicol;
+ char *p, *mtd_id, *semicol, *open_parenth;

/*
* Replace the first ';' by a NULL char so strrchr can work
@@ -238,6 +238,14 @@ static int mtdpart_setup_real(char *s)
if (semicol)
*semicol = '\0';

+ /*
+ * make sure that part-names with ":" will not be handled as
+ * part of the mtd-id with an ":"
+ */
+ open_parenth = strchr(s, '(');
+ if (open_parenth)
+ *open_parenth = '\0';
+
mtd_id = s;

/*
@@ -247,6 +255,10 @@ static int mtdpart_setup_real(char *s)
*/
p = strrchr(s, ':');

+ /* Restore the '(' now. */
+ if (open_parenth)
+ *open_parenth = '(';
+
/* Restore the ';' now. */
if (semicol)
*semicol = ';';