| Brad Bishop | 1a4b7ee | 2018-12-16 17:11:34 -0800 | [diff] [blame] | 1 | Incorrect command-line parameter validation in the Xorg X server can lead to |
| 2 | privilege elevation and/or arbitrary files overwrite, when the X server is |
| 3 | running with elevated privileges (ie when Xorg is installed with the setuid bit |
| 4 | set and started by a non-root user). The -modulepath argument can be used to |
| 5 | specify an insecure path to modules that are going to be loaded in the X server, |
| 6 | allowing to execute unprivileged code in the privileged process. The -logfile |
| 7 | argument can be used to overwrite arbitrary files in the file system, due to |
| 8 | incorrect checks in the parsing of the option. |
| 9 | |
| 10 | CVE: CVE-2018-14665 |
| 11 | Upstream-Status: Backport |
| 12 | Signed-off-by: Ross Burton <ross.burton@intel.com> |
| 13 | |
| 14 | From 50c0cf885a6e91c0ea71fb49fa8f1b7c86fe330e Mon Sep 17 00:00:00 2001 |
| 15 | From: Matthieu Herrb <matthieu@herrb.eu> |
| 16 | Date: Tue, 23 Oct 2018 21:29:08 +0200 |
| 17 | Subject: [PATCH] Disable -logfile and -modulepath when running with elevated |
| 18 | privileges |
| 19 | |
| 20 | Could cause privilege elevation and/or arbitrary files overwrite, when |
| 21 | the X server is running with elevated privileges (ie when Xorg is |
| 22 | installed with the setuid bit set and started by a non-root user). |
| 23 | |
| 24 | CVE-2018-14665 |
| 25 | |
| 26 | Issue reported by Narendra Shinde and Red Hat. |
| 27 | |
| 28 | Signed-off-by: Matthieu Herrb <matthieu@herrb.eu> |
| 29 | Reviewed-by: Alan Coopersmith <alan.coopersmith@oracle.com> |
| 30 | Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net> |
| 31 | Reviewed-by: Adam Jackson <ajax@redhat.com> |
| 32 | --- |
| 33 | hw/xfree86/common/xf86Init.c | 8 ++++++-- |
| 34 | 1 file changed, 6 insertions(+), 2 deletions(-) |
| 35 | |
| 36 | diff --git a/hw/xfree86/common/xf86Init.c b/hw/xfree86/common/xf86Init.c |
| 37 | index 6c25eda73..0f57efa86 100644 |
| 38 | --- a/hw/xfree86/common/xf86Init.c |
| 39 | +++ b/hw/xfree86/common/xf86Init.c |
| 40 | @@ -935,14 +935,18 @@ ddxProcessArgument(int argc, char **argv, int i) |
| 41 | /* First the options that are not allowed with elevated privileges */ |
| 42 | if (!strcmp(argv[i], "-modulepath")) { |
| 43 | CHECK_FOR_REQUIRED_ARGUMENT(); |
| 44 | - xf86CheckPrivs(argv[i], argv[i + 1]); |
| 45 | + if (xf86PrivsElevated()) |
| 46 | + FatalError("\nInvalid argument -modulepath " |
| 47 | + "with elevated privileges\n"); |
| 48 | xf86ModulePath = argv[i + 1]; |
| 49 | xf86ModPathFrom = X_CMDLINE; |
| 50 | return 2; |
| 51 | } |
| 52 | if (!strcmp(argv[i], "-logfile")) { |
| 53 | CHECK_FOR_REQUIRED_ARGUMENT(); |
| 54 | - xf86CheckPrivs(argv[i], argv[i + 1]); |
| 55 | + if (xf86PrivsElevated()) |
| 56 | + FatalError("\nInvalid argument -logfile " |
| 57 | + "with elevated privileges\n"); |
| 58 | xf86LogFile = argv[i + 1]; |
| 59 | xf86LogFileFrom = X_CMDLINE; |
| 60 | return 2; |
| 61 | -- |
| 62 | 2.18.1 |