From: Roman Smirnov r.smirnov@omp.ru
[ 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 r.smirnov@omp.ru Signed-off-by: Steve French stfrench@microsoft.com [ Adapted to older CIFS filesystem structure and mount option parsing ] Signed-off-by: Sasha Levin sashal@kernel.org --- fs/cifs/connect.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 2c0522d97e037..5fc418f9210a5 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -1915,6 +1915,11 @@ cifs_parse_mount_options(const char *mountdata, const char *devname, __func__); goto cifs_parse_mount_err; } + if (option < SMB_ECHO_INTERVAL_MIN || + option > SMB_ECHO_INTERVAL_MAX) { + cifs_dbg(VFS, "echo interval is out of bounds\n"); + goto cifs_parse_mount_err; + } vol->echo_interval = option; break; case Opt_snapshot: