gfs2: Switch from strlcpy to strscpy

commit 204c0300c4e99707e9fb6e57840aa1127060e63f upstream.

Switch from strlcpy to strscpy and make sure that @count is the size of
the smaller of the source and destination buffers.  This prevents
reading beyond the end of the source buffer when the source string isn't
null terminated.

Found by a modified version of syzkaller.

Suggested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 23c13156847638cec4dc90c5019affcbe4c73eaf..648f7336043f6a7ec5239d005153d426c64390dd 100644 (file)
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -384,8 +384,10 @@ static int init_names(struct gfs2_sbd *sdp, int silent)
        if (!table[0])
                table = sdp->sd_vfs->s_id;
 
-       strlcpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
-       strlcpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
+       BUILD_BUG_ON(GFS2_LOCKNAME_LEN > GFS2_FSNAME_LEN);
+
+       strscpy(sdp->sd_proto_name, proto, GFS2_LOCKNAME_LEN);
+       strscpy(sdp->sd_table_name, table, GFS2_LOCKNAME_LEN);
 
        table = sdp->sd_table_name;
        while ((table = strchr(table, '/')))
@@ -1417,13 +1419,13 @@ static int gfs2_parse_param(struct fs_context *fc, struct fs_parameter *param)
 
        switch (o) {
        case Opt_lockproto:
-               strlcpy(args->ar_lockproto, param->string, GFS2_LOCKNAME_LEN);
+               strscpy(args->ar_lockproto, param->string, GFS2_LOCKNAME_LEN);
                break;
        case Opt_locktable:
-               strlcpy(args->ar_locktable, param->string, GFS2_LOCKNAME_LEN);
+               strscpy(args->ar_locktable, param->string, GFS2_LOCKNAME_LEN);
                break;
        case Opt_hostdata:
-               strlcpy(args->ar_hostdata, param->string, GFS2_LOCKNAME_LEN);
+               strscpy(args->ar_hostdata, param->string, GFS2_LOCKNAME_LEN);
                break;
        case Opt_spectator:
                args->ar_spectator = 1;