linux-kernel - [PATCH 4/4] 9p p9mode2perm: remove useless strlcpy and check sscanf return code

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Message-Id: <20211102134608.1588018-5-dominique.martinet@atmark-techno.com>
Date:   Tue,  2 Nov 2021 22:46:08 +0900
From:   Dominique Martinet <dominique.martinet@...ark-techno.com>
To:     v9fs-developer@...ts.sourceforge.net
Cc:     linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        Eric Van Hensbergen <ericvh@...il.com>,
        Latchesar Ionkov <lucho@...kov.net>,
        Dominique Martinet <asmadeus@...ewreck.org>
Subject: [PATCH 4/4] 9p p9mode2perm: remove useless strlcpy and check sscanf return code

From: Dominique Martinet <asmadeus@...ewreck.org>

This is also a checkpatch warning fix but this one might have implications
so keeping it separate

Signed-off-by: Dominique Martinet <asmadeus@...ewreck.org>
---
 fs/9p/vfs_inode.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 139dfee23b98..328c338ff304 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -109,7 +109,7 @@ static int p9mode2perm(struct v9fs_session_info *v9ses,
 static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
 			       struct p9_wstat *stat, dev_t *rdev)
 {
-	int res;
+	int res, r;
 	u32 mode = stat->mode;
 
 	*rdev = 0;
@@ -127,11 +127,16 @@ static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
 		res |= S_IFIFO;
 	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
 		 && (v9ses->nodev == 0)) {
-		char type = 0, ext[32];
+		char type = 0;
 		int major = -1, minor = -1;
 
-		strlcpy(ext, stat->extension, sizeof(ext));
-		sscanf(ext, "%c %i %i", &type, &major, &minor);
+		r = sscanf(stat->extension, "%c %i %i", &type, &major, &minor);
+		if (r != 3) {
+			p9_debug(P9_DEBUG_ERROR,
+				 "invalid device string, umode will be bogus: %s\n",
+				 stat->extension);
+			return res;
+		}
 		switch (type) {
 		case 'c':
 			res |= S_IFCHR;
-- 
2.31.1