The echo_interval is not limited in any way during mounting, which makes it possible to write a large number to it. This can cause an overflow when multiplying ctx->echo_interval by HZ in match_server().

Add constraints for echo_interval to smb3_fs_context_parse_param().

Found by Linux Verification Center (linuxtesting.org) with Svace.

Fixes: adfeb3e00e8e1 ("cifs: Make echo interval tunable") Cc: stable@vger.kernel.org Signed-off-by: Roman Smirnov r.smirnov@omp.ru --- fs/smb/client/fs_context.c | 5 +++++ 1 file changed, 5 insertions(+)

diff --git a/fs/smb/client/fs_context.c b/fs/smb/client/fs_context.c index 8c73d4d60d1a..e38521a713a6 100644 --- a/fs/smb/client/fs_context.c +++ b/fs/smb/client/fs_context.c @@ -1377,6 +1377,11 @@ static int smb3_fs_context_parse_param(struct fs_context *fc, ctx->closetimeo = HZ * result.uint_32; break; case Opt_echo_interval: + if (result.uint_32 < SMB_ECHO_INTERVAL_MIN || + result.uint_32 > SMB_ECHO_INTERVAL_MAX) { + cifs_errorf(fc, "echo interval is out of bounds\n"); + goto cifs_parse_mount_err; + } ctx->echo_interval = result.uint_32; break; case Opt_snapshot: