Commit 5b29891f authored by Murad Masimov's avatar Murad Masimov Committed by Steve French
Browse files

cifs: Fix integer overflow while processing acdirmax mount option 



User-provided mount parameter acdirmax of type u32 is intended to have
an upper limit, but before it is validated, the value is converted from
seconds to jiffies which can lead to an integer overflow.

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

Fixes: 4c9f9481 ("cifs: Add new mount parameter "acdirmax" to allow caching directory metadata")
Signed-off-by: default avatarMurad Masimov <m.masimov@mt-integration.ru>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 7489161b

fs/smb/client/fs_context.c

+2 −2
Original line number Diff line number Diff line
@@ -1351,11 +1351,11 @@ static int smb3_fs_context_parse_param(struct fs_context *fc, 
		ctx->acregmax = HZ * result.uint_32;

		break;

	case Opt_acdirmax:

		ctx->acdirmax = HZ * result.uint_32;

		if (ctx->acdirmax > CIFS_MAX_ACTIMEO) {

		if (result.uint_32 > CIFS_MAX_ACTIMEO / HZ) {

			cifs_errorf(fc, "acdirmax too large\n");

			goto cifs_parse_mount_err;

		}

		ctx->acdirmax = HZ * result.uint_32;

		break;

	case Opt_actimeo:

		if (HZ * result.uint_32 > CIFS_MAX_ACTIMEO) {