git: d1b7ff3dac57 - stable/13 - ffs: Correct the input size check in sysctl_ffs_fsck()

[Mark Johnston]

The branch stable/13 has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=d1b7ff3dac5727fba692e7de999e9b6834b72659

commit d1b7ff3dac5727fba692e7de999e9b6834b72659
Author:     Mark Johnston <markj at FreeBSD.org>
AuthorDate: 2021-05-31 22:56:34 +0000
Commit:     Mark Johnston <markj at FreeBSD.org>
CommitDate: 2021-06-07 01:03:49 +0000

    ffs: Correct the input size check in sysctl_ffs_fsck()
    
    Make sure we return an error if no input was specified, since
    SYSCTL_IN() will report success in that case.
    
    Reported by:    KMSAN
    Reviewed by:    mckusick
    Sponsored by:   The FreeBSD Foundation
    
    (cherry picked from commit b2f9575646f89cdddcad76acae3e9305535506a2)
---
 sys/ufs/ffs/ffs_alloc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sys/ufs/ffs/ffs_alloc.c b/sys/ufs/ffs/ffs_alloc.c
index c7a1e2dec15e..c895c8c7bf07 100644
--- a/sys/ufs/ffs/ffs_alloc.c
+++ b/sys/ufs/ffs/ffs_alloc.c
@@ -3211,9 +3211,9 @@ sysctl_ffs_fsck(SYSCTL_HANDLER_ARGS)
 	cap_rights_t rights;
 	int filetype, error;
 
-	if (req->newlen > sizeof cmd)
+	if (req->newptr == NULL || req->newlen > sizeof(cmd))
 		return (EBADRPC);
-	if ((error = SYSCTL_IN(req, &cmd, sizeof cmd)) != 0)
+	if ((error = SYSCTL_IN(req, &cmd, sizeof(cmd))) != 0)
 		return (error);
 	if (cmd.version != FFS_CMD_VERSION)
 		return (ERPCMISMATCH);