merged: https://github.com/SELinuxProject/selinux/pull/142 On Sun, Apr 7, 2019 at 1:59 PM Nicolas Iooss <nicolas.iooss@xxxxxxx> wrote: > > On Fri, Apr 5, 2019 at 9:04 PM William Roberts <bill.c.roberts@xxxxxxxxx> wrote: > > > > On Fri, Apr 5, 2019 at 12:01 PM Joshua Brindle > > <joshua.brindle@xxxxxxxxxxxxxxx> wrote: > > > > > > It seems validatetrans support was never added to libselinux, despite being added to > > > selinuxfs in kernel version 4.5 > > > > > > There is a utility to test, however the targeted policy has no validatetrans rules so some must be added: > > > > > > $ cat validatetrans.cil > > > (mlsvalidatetrans db_table (and (or (or (or (eq l1 l2) (and (eq t3 unconfined_t) (domby l1 l2))) (and (eq t3 unconfined_t) (dom l1 l2))) (and (eq t3 unconfined_t) (incomp l1 l2))) (or (or (or (eq l1 h2) (and (eq t3 unconfined_t) (domby h1 h2))) (and (eq t3 unconfined_t) (dom h1 h2))) (and (eq t3 unconfined_t) (incomp h1 h2))))) > > > > > > $ sudo semodule -i validatetrans.cil > > > > > > $ ./validatetrans system_u:system_r:kernel_t:s0 system_u:system_r:init_t:s0:c0 db_table system_u:system_r: # invalid context here > > > opening /sys/fs/selinux/validatetrans > > > security_validatetrans returned -1 errno: Invalid argument > > > > > > $ ./validatetrans system_u:system_r:kernel_t:s0 system_u:system_r:init_t:s0:c0 db_table system_u:system_r:init_t:s0 > > > opening /sys/fs/selinux/validatetrans > > > security_validatetrans returned -1 errno: Operation not permitted > > > > > > $ ./validatetrans system_u:system_r:kernel_t:s0 system_u:system_r:init_t:s0:c0 db_table system_u:system_r:unconfined_t:s0 > > > opening /sys/fs/selinux/validatetrans > > > security_validatetrans returned 0 errno: Success > > > > > > Signed-off-by: Joshua Brindle <joshua.brindle@xxxxxxxxxxxxxxx> > > > --- > > > libselinux/include/selinux/selinux.h | 13 +++ > > > libselinux/man/man3/security_compute_av.3 | 13 ++- > > > libselinux/man/man3/security_validatetrans.c | 1 + > > > .../man/man3/security_validatetrans_raw.c | 1 + > > > libselinux/src/selinux_internal.h | 2 + > > > libselinux/src/validatetrans.c | 94 +++++++++++++++++++ > > > libselinux/utils/.gitignore | 1 + > > > libselinux/utils/validatetrans.c | 30 ++++++ > > > 8 files changed, 154 insertions(+), 1 deletion(-) > > > create mode 100644 libselinux/man/man3/security_validatetrans.c > > > create mode 100644 libselinux/man/man3/security_validatetrans_raw.c > > > create mode 100644 libselinux/src/validatetrans.c > > > create mode 100644 libselinux/utils/validatetrans.c > > > > > > diff --git a/libselinux/include/selinux/selinux.h b/libselinux/include/selinux/selinux.h > > > index a34d54fc..f54f236b 100644 > > > --- a/libselinux/include/selinux/selinux.h > > > +++ b/libselinux/include/selinux/selinux.h > > > @@ -255,6 +255,19 @@ extern int security_compute_user_raw(const char * scon, > > > const char *username, > > > char *** con); > > > > > > +/* Validate a transition. This determines whether a transition from scon to newcon > > > + using tcon as the target for object class tclass is valid in the loaded policy. > > > + This checks against the mlsvalidatetrans and validatetrans constraints in the loaded policy. > > > + Returns 0 if allowed and -1 if an error occured with errno set */ > > > +extern int security_validatetrans(const char *scon, > > > + const char *tcon, > > > + security_class_t tclass, > > > + const char *newcon); > > > +extern int security_validatetrans_raw(const char *scon, > > > + const char *tcon, > > > + security_class_t tclass, > > > + const char *newcon); > > > + > > > /* Load a policy configuration. */ > > > extern int security_load_policy(void *data, size_t len); > > > > > > diff --git a/libselinux/man/man3/security_compute_av.3 b/libselinux/man/man3/security_compute_av.3 > > > index 2aade5fe..a7181bed 100644 > > > --- a/libselinux/man/man3/security_compute_av.3 > > > +++ b/libselinux/man/man3/security_compute_av.3 > > > @@ -1,7 +1,7 @@ > > > .TH "security_compute_av" "3" "1 January 2004" "russell@xxxxxxxxxxxx" "SELinux API documentation" > > > .SH "NAME" > > > security_compute_av, security_compute_av_flags, security_compute_create, security_compute_create_name, security_compute_relabel, > > > -security_compute_member, security_compute_user, security_get_initial_context \- query > > > +security_compute_member, security_compute_user, security_validatetrans, security_get_initial_context \- query > > > the SELinux policy database in the kernel > > > . > > > .SH "SYNOPSIS" > > > @@ -35,6 +35,10 @@ the SELinux policy database in the kernel > > > .sp > > > .BI "int security_compute_user_raw(char *" scon ", const char *" username ", char ***" con ); > > > .sp > > > +.BI "int security_validatetrans(char *" scon ", const char *" tcon ", security_class_t "tclass ", char *" newcon ); > > > +.sp > > > +.BI "int security_validatetrans_raw(char *" scon ", const char *" tcon ", security_class_t "tclass ", char *" newcon ); > > > +.sp > > > .BI "int security_get_initial_context(const char *" name ", char **" con ); > > > .sp > > > .BI "int security_get_initial_context_raw(const char *" name ", char **" con ); > > > @@ -100,6 +104,12 @@ is used to determine the set of user contexts that can be reached from a > > > source context. It is mainly used by > > > .BR get_ordered_context_list (). > > > > > > +.BR security_validatetrans () > > > +is used to determine if a transition from scon to newcon using tcon as the object > > > +is valid for object class tclass. This checks against the mlsvalidatetrans and > > > +validatetrans constraints in the loaded policy. Returns 0 if allowed, and -1 > > > +if an error occured with errno set. > > > + > > > .BR security_get_initial_context () > > > is used to get the context of a kernel initial security identifier specified by > > > .I name > > > @@ -111,6 +121,7 @@ is used to get the context of a kernel initial security identifier specified by > > > .BR \%security_compute_relabel_raw (), > > > .BR \%security_compute_member_raw (), > > > .BR \%security_compute_user_raw () > > > +.BR \%security_validatetrans_raw () > > > and > > > .BR \%security_get_initial_context_raw () > > > behave identically to their non-raw counterparts but do not perform context > > > diff --git a/libselinux/man/man3/security_validatetrans.c b/libselinux/man/man3/security_validatetrans.c > > > new file mode 100644 > > > index 00000000..a60bca4d > > > --- /dev/null > > > +++ b/libselinux/man/man3/security_validatetrans.c > > > @@ -0,0 +1 @@ > > > +.so man3/security_compute_av.3 > > > diff --git a/libselinux/man/man3/security_validatetrans_raw.c b/libselinux/man/man3/security_validatetrans_raw.c > > > new file mode 100644 > > > index 00000000..a60bca4d > > > --- /dev/null > > > +++ b/libselinux/man/man3/security_validatetrans_raw.c > > > @@ -0,0 +1 @@ > > > +.so man3/security_compute_av.3 > > > diff --git a/libselinux/src/selinux_internal.h b/libselinux/src/selinux_internal.h > > > index 70b5025d..acd59c7c 100644 > > > --- a/libselinux/src/selinux_internal.h > > > +++ b/libselinux/src/selinux_internal.h > > > @@ -29,6 +29,8 @@ hidden_proto(selinux_mkload_policy) > > > hidden_proto(security_compute_create_name_raw) > > > hidden_proto(security_compute_member_raw) > > > hidden_proto(security_compute_relabel_raw) > > > + hidden_proto(security_validatetrans) > > > + hidden_proto(security_validatetrans_raw) > > > hidden_proto(is_selinux_enabled) > > > hidden_proto(is_selinux_mls_enabled) > > > hidden_proto(freecon) > > > diff --git a/libselinux/src/validatetrans.c b/libselinux/src/validatetrans.c > > > new file mode 100644 > > > index 00000000..2aa300cf > > > --- /dev/null > > > +++ b/libselinux/src/validatetrans.c > > > @@ -0,0 +1,94 @@ > > > +#include <unistd.h> > > > +#include <sys/types.h> > > > +#include <fcntl.h> > > > +#include <stdlib.h> > > > +#include <stdio.h> > > > +#include <errno.h> > > > +#include <string.h> > > > +#include <limits.h> > > > +#include "selinux_internal.h" > > > +#include "policy.h" > > > +#include "mapping.h" > > > + > > > +int security_validatetrans_raw(const char *scon, > > > + const char *tcon, > > > + security_class_t tclass, > > > + const char *newcon) > > > +{ > > > + char path[PATH_MAX]; > > > + char *buf = NULL; > > > + int size, bufsz; > > > + int fd, ret = -1; > > > + errno = ENOENT; > > > + > > > + if (!selinux_mnt) { > > > + return -1; > > > + } > > > + > > > + snprintf(path, sizeof path, "%s/validatetrans", selinux_mnt); > > > + fd = open(path, O_WRONLY | O_CLOEXEC); > > > + if (fd < 0) { > > > + return -1; > > > + } > > > + > > > + errno = EINVAL; > > > + size = selinux_page_size; > > > + buf = malloc(size); > > > + if (!buf) { > > > + goto out; > > > + } > > > + > > > + bufsz = snprintf(buf, size, "%s %s %hu %s", scon, tcon, unmap_class(tclass), newcon); > > > + if (bufsz >= size || bufsz < 0) { > > > + // It got truncated or there was an encoding error > > > + goto out; > > > + } > > > + > > > + // clear errno for write() > > > + errno = 0; > > > + ret = write(fd, buf, strlen(buf)); > > > + if (ret > 0) { > > > + // The kernel returns the bytes written on success, not 0 as noted in the commit message > > > + ret = 0; > > > + } > > > +out: > > > + free(buf); > > > + close(fd); > > > + return ret; > > > +} > > > + > > > +hidden_def(security_validatetrans_raw) > > > + > > > +int security_validatetrans(const char *scon, > > > + const char *tcon, > > > + security_class_t tclass, > > > + const char *newcon) > > > +{ > > > + int ret = -1; > > > + char *rscon = NULL; > > > + char *rtcon = NULL; > > > + char *rnewcon = NULL; > > > + > > > + if (selinux_trans_to_raw_context(scon, &rscon)) { > > > + goto out; > > > + } > > > + > > > + if (selinux_trans_to_raw_context(tcon, &rtcon)) { > > > + goto out; > > > + } > > > + > > > + if (selinux_trans_to_raw_context(newcon, &rnewcon)) { > > > + goto out; > > > + } > > > + > > > + ret = security_validatetrans_raw(rscon, rtcon, tclass, rnewcon); > > > + > > > +out: > > > + freecon(rnewcon); > > > + freecon(rtcon); > > > + freecon(rscon); > > > + > > > + return ret; > > > +} > > > + > > > +hidden_def(security_validatetrans) > > > diff --git a/libselinux/utils/.gitignore b/libselinux/utils/.gitignore > > > index 5cd01025..aba18a3c 100644 > > > --- a/libselinux/utils/.gitignore > > > +++ b/libselinux/utils/.gitignore > > > @@ -25,3 +25,4 @@ setenforce > > > setfilecon > > > togglesebool > > > selinux_check_access > > > +validatetrans > > > diff --git a/libselinux/utils/validatetrans.c b/libselinux/utils/validatetrans.c > > > new file mode 100644 > > > index 00000000..1db33e66 > > > --- /dev/null > > > +++ b/libselinux/utils/validatetrans.c > > > @@ -0,0 +1,30 @@ > > > +#include <unistd.h> > > > +#include <sys/types.h> > > > +#include <stdio.h> > > > +#include <stdlib.h> > > > +#include <string.h> > > > +#include <errno.h> > > > +#include <selinux/selinux.h> > > > + > > > +int main(int argc, char **argv) > > > +{ > > > + security_class_t tclass; > > > + int ret; > > > + > > > + if (argc != 5) { > > > + fprintf(stderr, "usage: %s scontext tcontext tclass newcontext\n", > > > + argv[0]); > > > + exit(1); > > > + } > > > + > > > + tclass = string_to_security_class(argv[3]); > > > + if (!tclass) { > > > + fprintf(stderr, "%s: invalid class '%s'\n", argv[0], argv[3]); > > > + exit(2); > > > + } > > > + > > > + ret = security_validatetrans(argv[1], argv[2], tclass, argv[4]); > > > + printf("security_validatetrans returned %d errno: %s\n", ret, strerror(errno)); > > > + > > > + return ret; > > > +} > > > -- > > > 2.17.2 > > > > > > > ack - staged: https://github.com/SELinuxProject/selinux/pull/142 > > Acked-by: Nicolas Iooss <nicolas.iooss@xxxxxxx> > > Thanks! > Nicolas >
