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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Boris Brezillon <boris.brezillon@collabora.com>,
        Ron Minnich <rminnich@google.com>,
        Richard Weinberger <richard@nod.at>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 097/121] mtd: parser: cmdline: Support MTD names containing one or more colons
Date:   Tue, 29 Sep 2020 13:00:41 +0200
Message-Id: <20200929105934.983935666@linuxfoundation.org>
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From: Boris Brezillon <boris.brezillon@collabora.com>

[ Upstream commit eb13fa0227417e84aecc3bd9c029d376e33474d3 ]

Looks like some drivers define MTD names with a colon in it, thus
making mtdpart= parsing impossible. Let's fix the parser to gracefully
handle that case: the last ':' in a partition definition sequence is
considered instead of the first one.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Ron Minnich <rminnich@google.com>
Tested-by: Ron Minnich <rminnich@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/mtd/cmdlinepart.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/cmdlinepart.c b/drivers/mtd/cmdlinepart.c
index fbd5affc0acfe..04fd845de05fb 100644
--- a/drivers/mtd/cmdlinepart.c
+++ b/drivers/mtd/cmdlinepart.c
@@ -228,12 +228,29 @@ 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;
+		char *p, *mtd_id, *semicol;
+
+		/*
+		 * Replace the first ';' by a NULL char so strrchr can work
+		 * properly.
+		 */
+		semicol = strchr(s, ';');
+		if (semicol)
+			*semicol = '\0';
 
 		mtd_id = s;
 
-		/* fetch <mtd-id> */
-		p = strchr(s, ':');
+		/*
+		 * fetch <mtd-id>. We use strrchr to ignore all ':' that could
+		 * be present in the MTD name, only the last one is interpreted
+		 * as an <mtd-id>/<part-definition> separator.
+		 */
+		p = strrchr(s, ':');
+
+		/* Restore the ';' now. */
+		if (semicol)
+			*semicol = ';';
+
 		if (!p) {
 			pr_err("no mtd-id\n");
 			return -EINVAL;
-- 
2.25.1