diff options
Diffstat (limited to 'poky/meta/recipes-extended/shadow/files/CVE-2018-7169.patch')
| -rw-r--r-- | poky/meta/recipes-extended/shadow/files/CVE-2018-7169.patch | 186 |
1 files changed, 0 insertions, 186 deletions
diff --git a/poky/meta/recipes-extended/shadow/files/CVE-2018-7169.patch b/poky/meta/recipes-extended/shadow/files/CVE-2018-7169.patch deleted file mode 100644 index 36887d44e..000000000 --- a/poky/meta/recipes-extended/shadow/files/CVE-2018-7169.patch +++ /dev/null @@ -1,186 +0,0 @@ -From fb28c99b8a66ff2605c5cb96abc0a4d975f92de0 Mon Sep 17 00:00:00 2001 -From: Aleksa Sarai <asarai@suse.de> -Date: Thu, 15 Feb 2018 23:49:40 +1100 -Subject: [PATCH] newgidmap: enforce setgroups=deny if self-mapping a group - -This is necessary to match the kernel-side policy of "self-mapping in a -user namespace is fine, but you cannot drop groups" -- a policy that was -created in order to stop user namespaces from allowing trivial privilege -escalation by dropping supplementary groups that were "blacklisted" from -certain paths. - -This is the simplest fix for the underlying issue, and effectively makes -it so that unless a user has a valid mapping set in /etc/subgid (which -only administrators can modify) -- and they are currently trying to use -that mapping -- then /proc/$pid/setgroups will be set to deny. This -workaround is only partial, because ideally it should be possible to set -an "allow_setgroups" or "deny_setgroups" flag in /etc/subgid to allow -administrators to further restrict newgidmap(1). - -We also don't write anything in the "allow" case because "allow" is the -default, and users may have already written "deny" even if they -technically are allowed to use setgroups. And we don't write anything if -the setgroups policy is already "deny". - -Ref: https://bugs.launchpad.net/ubuntu/+source/shadow/+bug/1729357 -Fixes: CVE-2018-7169 - -Upstream-Status: Backport [https://github.com/shadow-maint/shadow/commit/fb28c99b8a66ff2605c5cb96abc0a4d975f92de0] -Reported-by: Craig Furman <craig.furman89@gmail.com> -Signed-off-by: Aleksa Sarai <asarai@suse.de> -Signed-off-by: Jagadeesh Krishnanjanappa <jkrishnanjanappa@mvista.com> ---- - src/newgidmap.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++------ - 1 file changed, 80 insertions(+), 9 deletions(-) - -diff --git a/src/newgidmap.c b/src/newgidmap.c -index b1e33513..59a2e75c 100644 ---- a/src/newgidmap.c -+++ b/src/newgidmap.c -@@ -46,32 +46,37 @@ - */ - const char *Prog; - --static bool verify_range(struct passwd *pw, struct map_range *range) -+ -+static bool verify_range(struct passwd *pw, struct map_range *range, bool *allow_setgroups) - { - /* An empty range is invalid */ - if (range->count == 0) - return false; - -- /* Test /etc/subgid */ -- if (have_sub_gids(pw->pw_name, range->lower, range->count)) -+ /* Test /etc/subgid. If the mapping is valid then we allow setgroups. */ -+ if (have_sub_gids(pw->pw_name, range->lower, range->count)) { -+ *allow_setgroups = true; - return true; -+ } - -- /* Allow a process to map it's own gid */ -- if ((range->count == 1) && (pw->pw_gid == range->lower)) -+ /* Allow a process to map its own gid. */ -+ if ((range->count == 1) && (pw->pw_gid == range->lower)) { -+ /* noop -- if setgroups is enabled already we won't disable it. */ - return true; -+ } - - return false; - } - - static void verify_ranges(struct passwd *pw, int ranges, -- struct map_range *mappings) -+ struct map_range *mappings, bool *allow_setgroups) - { - struct map_range *mapping; - int idx; - - mapping = mappings; - for (idx = 0; idx < ranges; idx++, mapping++) { -- if (!verify_range(pw, mapping)) { -+ if (!verify_range(pw, mapping, allow_setgroups)) { - fprintf(stderr, _( "%s: gid range [%lu-%lu) -> [%lu-%lu) not allowed\n"), - Prog, - mapping->upper, -@@ -89,6 +94,70 @@ static void usage(void) - exit(EXIT_FAILURE); - } - -+void write_setgroups(int proc_dir_fd, bool allow_setgroups) -+{ -+ int setgroups_fd; -+ char *policy, policy_buffer[4096]; -+ -+ /* -+ * Default is "deny", and any "allow" will out-rank a "deny". We don't -+ * forcefully write an "allow" here because the process we are writing -+ * mappings for may have already set themselves to "deny" (and "allow" -+ * is the default anyway). So allow_setgroups == true is a noop. -+ */ -+ policy = "deny\n"; -+ if (allow_setgroups) -+ return; -+ -+ setgroups_fd = openat(proc_dir_fd, "setgroups", O_RDWR|O_CLOEXEC); -+ if (setgroups_fd < 0) { -+ /* -+ * If it's an ENOENT then we are on too old a kernel for the setgroups -+ * code to exist. Emit a warning and bail on this. -+ */ -+ if (ENOENT == errno) { -+ fprintf(stderr, _("%s: kernel doesn't support setgroups restrictions\n"), Prog); -+ goto out; -+ } -+ fprintf(stderr, _("%s: couldn't open process setgroups: %s\n"), -+ Prog, -+ strerror(errno)); -+ exit(EXIT_FAILURE); -+ } -+ -+ /* -+ * Check whether the policy is already what we want. /proc/self/setgroups -+ * is write-once, so attempting to write after it's already written to will -+ * fail. -+ */ -+ if (read(setgroups_fd, policy_buffer, sizeof(policy_buffer)) < 0) { -+ fprintf(stderr, _("%s: failed to read setgroups: %s\n"), -+ Prog, -+ strerror(errno)); -+ exit(EXIT_FAILURE); -+ } -+ if (!strncmp(policy_buffer, policy, strlen(policy))) -+ goto out; -+ -+ /* Write the policy. */ -+ if (lseek(setgroups_fd, 0, SEEK_SET) < 0) { -+ fprintf(stderr, _("%s: failed to seek setgroups: %s\n"), -+ Prog, -+ strerror(errno)); -+ exit(EXIT_FAILURE); -+ } -+ if (dprintf(setgroups_fd, "%s", policy) < 0) { -+ fprintf(stderr, _("%s: failed to setgroups %s policy: %s\n"), -+ Prog, -+ policy, -+ strerror(errno)); -+ exit(EXIT_FAILURE); -+ } -+ -+out: -+ close(setgroups_fd); -+} -+ - /* - * newgidmap - Set the gid_map for the specified process - */ -@@ -103,6 +172,7 @@ int main(int argc, char **argv) - struct stat st; - struct passwd *pw; - int written; -+ bool allow_setgroups = false; - - Prog = Basename (argv[0]); - -@@ -145,7 +215,7 @@ int main(int argc, char **argv) - (unsigned long) getuid ())); - return EXIT_FAILURE; - } -- -+ - /* Get the effective uid and effective gid of the target process */ - if (fstat(proc_dir_fd, &st) < 0) { - fprintf(stderr, _("%s: Could not stat directory for target %u\n"), -@@ -177,8 +247,9 @@ int main(int argc, char **argv) - if (!mappings) - usage(); - -- verify_ranges(pw, ranges, mappings); -+ verify_ranges(pw, ranges, mappings, &allow_setgroups); - -+ write_setgroups(proc_dir_fd, allow_setgroups); - write_mapping(proc_dir_fd, ranges, mappings, "gid_map"); - sub_gid_close(); - --- -2.13.3 - |
