From: Roman Smirnov Date: Mon, 31 Mar 2025 08:22:49 +0000 (+0300) Subject: cifs: fix integer overflow in match_server() X-Git-Tag: v5.15.181~98 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=32d554841024a70dc69bbc63545f80116810a270;p=thirdparty%2Fkernel%2Fstable.git cifs: fix integer overflow in match_server() [ Upstream commit 2510859475d7f46ed7940db0853f3342bf1b65ee ] 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 Signed-off-by: Steve French Signed-off-by: Sasha Levin --- diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c index 24c42043a2271..c3a71c69d3395 100644 --- a/fs/cifs/fs_context.c +++ b/fs/cifs/fs_context.c @@ -1088,6 +1088,11 @@ 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: