| From 5018a0c016495155ee598b7e0167b43d5d902414 Mon Sep 17 00:00:00 2001 |
| From: Jann Horn <jannh@google.com> |
| Date: Sat, 14 Jul 2018 03:47:50 -0700 |
| Subject: [PATCH] fusermount: refuse unknown options |
| |
| Blacklists are notoriously fragile; especially if the kernel wishes to add |
| some security-critical mount option at a later date, all existing systems |
| with older versions of fusermount installed will suddenly have a security |
| problem. |
| Additionally, if the kernel's option parsing became a tiny bit laxer, the |
| blacklist could probably be bypassed. |
| |
| Whitelist known-harmless flags instead, even if it's slightly more |
| inconvenient. |
| |
| CVE: CVE-2018-10906 |
| Upstream-Status: Backport [https://github.com/libfuse/libfuse/commit/5018a0c016495155ee598b7e0167b43d5d902414] |
| |
| Signed-off-by: Jagadeesh Krishnanjanappa <jkrishnanjanappa@mvista.com> |
| --- |
| util/fusermount.c | 8 +++++++- |
| 1 file changed, 7 insertions(+), 1 deletion(-) |
| |
| diff --git a/util/fusermount.c b/util/fusermount.c |
| index 4e0f51a..2792407 100644 |
| --- a/util/fusermount.c |
| +++ b/util/fusermount.c |
| @@ -819,10 +819,16 @@ static int do_mount(const char *mnt, char **typep, mode_t rootmode, |
| flags |= flag; |
| else |
| flags &= ~flag; |
| - } else { |
| + } else if (opt_eq(s, len, "default_permissions") || |
| + opt_eq(s, len, "allow_other") || |
| + begins_with(s, "max_read=") || |
| + begins_with(s, "blksize=")) { |
| memcpy(d, s, len); |
| d += len; |
| *d++ = ','; |
| + } else { |
| + fprintf(stderr, "%s: unknown option '%.*s'\n", progname, len, s); |
| + exit(1); |
| } |
| } |
| } |
| -- |
| 2.13.3 |
| |