| Message ID | 20240725161107.1446978-1-vmojzis@redhat.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v4] libsemanage: Preserve file context and ownership in policy store | expand |
On Thu, Jul 25, 2024 at 12:11 PM Vit Mojzis <vmojzis@redhat.com> wrote: > > Make sure that file context (all parts) and ownership of > files/directories in policy store does not change no matter which user > and under which context executes policy rebuild. > > Fixes: > # semodule -B > # ls -lZ /etc/selinux/targeted/contexts/files > > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 421397 Jul 11 09:57 file_contexts > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 593470 Jul 11 09:57 file_contexts.bin > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 14704 Jul 11 09:57 file_contexts.homedirs > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 20289 Jul 11 09:57 file_contexts.homedirs.bin > > SELinux user changed from system_u to the user used to execute semodule > > # capsh --user=testuser --caps="cap_dac_override,cap_chown+eip" --addamb=cap_dac_override,cap_chown -- -c "semodule -B" > # ls -lZ /etc/selinux/targeted/contexts/files > > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 421397 Jul 19 09:10 file_contexts > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 593470 Jul 19 09:10 file_contexts.bin > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 14704 Jul 19 09:10 file_contexts.homedirs > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 20289 Jul 19 09:10 file_contexts.homedirs.bin > > Both file context and ownership changed -- causes remote login > failures and other issues in some scenarios. > > Signed-off-by: Vit Mojzis <vmojzis@redhat.com> > --- > libsemanage/src/semanage_store.c | 31 +++++++++++++++++++++++++++++++ > libsemanage/src/semanage_store.h | 1 + > 2 files changed, 32 insertions(+) > > diff --git a/libsemanage/src/semanage_store.c b/libsemanage/src/semanage_store.c > index 27c5d349..95596a93 100644 > --- a/libsemanage/src/semanage_store.c > +++ b/libsemanage/src/semanage_store.c > @@ -36,6 +36,7 @@ typedef struct dbase_policydb dbase_t; > #include "database_policydb.h" > #include "handle.h" > > +#include <selinux/restorecon.h> > #include <selinux/selinux.h> > #include <sepol/policydb.h> > #include <sepol/module.h> I get the following error when building: $ make DESTDIR=~/obj install > make.out In file included from semanage_store.c:39: /home/sdsmall/obj/usr/include/selinux/restorecon.h:137:52: error: ‘struct selabel_handle’ declared inside parameter list will not be visible outside of this definition or declaration [-Werror] 137 | extern void selinux_restorecon_set_sehandle(struct selabel_handle *hndl); | ^~~~~~~~~~~~~~ cc1: all warnings being treated as errors make[2]: *** [Makefile:111: semanage_store.o] Error 1 make[1]: *** [Makefile:15: install] Error 2 make: *** [Makefile:40: install] Error 1 It appear that either we need to modify libselinux/include/selinux/restorecon.h to #include <selinux/handle.h> prior to using selabel_handle or to add it prior to including selinux/restorecon.h here. The first option seems correct to me.
On Thu, Jul 25, 2024 at 12:11 PM Vit Mojzis <vmojzis@redhat.com> wrote: > > Make sure that file context (all parts) and ownership of > files/directories in policy store does not change no matter which user > and under which context executes policy rebuild. > > Fixes: > # semodule -B > # ls -lZ /etc/selinux/targeted/contexts/files > > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 421397 Jul 11 09:57 file_contexts > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 593470 Jul 11 09:57 file_contexts.bin > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 14704 Jul 11 09:57 file_contexts.homedirs > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 20289 Jul 11 09:57 file_contexts.homedirs.bin > > SELinux user changed from system_u to the user used to execute semodule > > # capsh --user=testuser --caps="cap_dac_override,cap_chown+eip" --addamb=cap_dac_override,cap_chown -- -c "semodule -B" > # ls -lZ /etc/selinux/targeted/contexts/files > > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 421397 Jul 19 09:10 file_contexts > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 593470 Jul 19 09:10 file_contexts.bin > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 14704 Jul 19 09:10 file_contexts.homedirs > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 20289 Jul 19 09:10 file_contexts.homedirs.bin > > Both file context and ownership changed -- causes remote login > failures and other issues in some scenarios. > > Signed-off-by: Vit Mojzis <vmojzis@redhat.com> With the selinux/restorecon.h fix applied first, Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com> > --- > libsemanage/src/semanage_store.c | 31 +++++++++++++++++++++++++++++++ > libsemanage/src/semanage_store.h | 1 + > 2 files changed, 32 insertions(+) > > diff --git a/libsemanage/src/semanage_store.c b/libsemanage/src/semanage_store.c > index 27c5d349..95596a93 100644 > --- a/libsemanage/src/semanage_store.c > +++ b/libsemanage/src/semanage_store.c > @@ -36,6 +36,7 @@ typedef struct dbase_policydb dbase_t; > #include "database_policydb.h" > #include "handle.h" > > +#include <selinux/restorecon.h> > #include <selinux/selinux.h> > #include <sepol/policydb.h> > #include <sepol/module.h> > @@ -767,6 +768,7 @@ int semanage_copy_file(const char *src, const char *dst, mode_t mode, > if (!retval && rename(tmp, dst) == -1) > return -1; > > + semanage_setfiles(dst); > out: > errno = errsv; > return retval; > @@ -819,6 +821,8 @@ static int semanage_copy_dir_flags(const char *src, const char *dst, int flag) > goto cleanup; > } > umask(mask); > + > + semanage_setfiles(dst); > } > > for (i = 0; i < len; i++) { > @@ -837,6 +841,7 @@ static int semanage_copy_dir_flags(const char *src, const char *dst, int flag) > goto cleanup; > } > umask(mask); > + semanage_setfiles(path2); > } else if (S_ISREG(sb.st_mode) && flag == 1) { > mask = umask(0077); > if (semanage_copy_file(path, path2, sb.st_mode, > @@ -938,6 +943,7 @@ int semanage_mkdir(semanage_handle_t *sh, const char *path) > > } > umask(mask); > + semanage_setfiles(path); > } > else { > /* check that it really is a directory */ > @@ -1614,16 +1620,19 @@ static int semanage_validate_and_compile_fcontexts(semanage_handle_t * sh) > semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC)) != 0) { > goto cleanup; > } > + semanage_setfiles(semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_BIN)); > > if (sefcontext_compile(sh, > semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_LOCAL)) != 0) { > goto cleanup; > } > + semanage_setfiles(semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_LOCAL_BIN)); > > if (sefcontext_compile(sh, > semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_HOMEDIRS)) != 0) { > goto cleanup; > } > + semanage_setfiles(semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_HOMEDIRS_BIN)); > > status = 0; > cleanup: > @@ -3018,3 +3027,25 @@ int semanage_nc_sort(semanage_handle_t * sh, const char *buf, size_t buf_len, > > return 0; > } > + > +/* Make sure the file context and ownership of files in the policy > + * store does not change */ > +void semanage_setfiles(const char *path){ > + struct stat sb; > + int fd; > + /* Fix the user and role portions of the context, ignore errors > + * since this is not a critical operation */ > + selinux_restorecon(path, SELINUX_RESTORECON_SET_SPECFILE_CTX | SELINUX_RESTORECON_IGNORE_NOENTRY); > + > + /* Make sure "path" is owned by root */ > + if ((geteuid() != 0 || getegid() != 0) && > + ((fd = open(path, O_RDONLY)) != -1)){ > + /* Skip files with the SUID or SGID bit set -- abuse protection */ > + if ((fstat(fd, &sb) != -1) && > + !(S_ISREG(sb.st_mode) && > + (sb.st_mode & (S_ISUID | S_ISGID)))) > + fchown(fd, 0, 0); > + > + close(fd); > + } > +} > diff --git a/libsemanage/src/semanage_store.h b/libsemanage/src/semanage_store.h > index 1fc77da8..e21dadeb 100644 > --- a/libsemanage/src/semanage_store.h > +++ b/libsemanage/src/semanage_store.h > @@ -124,6 +124,7 @@ int semanage_get_cil_paths(semanage_handle_t * sh, semanage_module_info_t *modin > int semanage_get_active_modules(semanage_handle_t *sh, > semanage_module_info_t **modinfo, int *num_modules); > > +void semanage_setfiles(const char *path); > > /* lock file routines */ > int semanage_get_trans_lock(semanage_handle_t * sh); > -- > 2.43.0 > >
On Fri, Jul 26, 2024 at 1:50 PM Stephen Smalley <stephen.smalley.work@gmail.com> wrote: > > On Thu, Jul 25, 2024 at 12:11 PM Vit Mojzis <vmojzis@redhat.com> wrote: > > > > Make sure that file context (all parts) and ownership of > > files/directories in policy store does not change no matter which user > > and under which context executes policy rebuild. > > > > Fixes: > > # semodule -B > > # ls -lZ /etc/selinux/targeted/contexts/files > > > > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 421397 Jul 11 09:57 file_contexts > > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 593470 Jul 11 09:57 file_contexts.bin > > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 14704 Jul 11 09:57 file_contexts.homedirs > > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 20289 Jul 11 09:57 file_contexts.homedirs.bin > > > > SELinux user changed from system_u to the user used to execute semodule > > > > # capsh --user=testuser --caps="cap_dac_override,cap_chown+eip" --addamb=cap_dac_override,cap_chown -- -c "semodule -B" > > # ls -lZ /etc/selinux/targeted/contexts/files > > > > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 421397 Jul 19 09:10 file_contexts > > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 593470 Jul 19 09:10 file_contexts.bin > > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 14704 Jul 19 09:10 file_contexts.homedirs > > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 20289 Jul 19 09:10 file_contexts.homedirs.bin > > > > Both file context and ownership changed -- causes remote login > > failures and other issues in some scenarios. > > > > Signed-off-by: Vit Mojzis <vmojzis@redhat.com> > > With the selinux/restorecon.h fix applied first, > > Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com> Ah, spoke too soon. The GitHub CI testing failed with this: semanage_store.c: In function ‘semanage_setfiles’: 520 semanage_store.c:3047:25: error: ignoring return value of ‘fchown’ declared with attribute ‘warn_unused_result’ [-Werror=unused-result] 521 3047 | fchown(fd, 0, 0); 522 | ^~~~~~~~~~~~~~~~
On Fri, Jul 26, 2024 at 1:54 PM Stephen Smalley <stephen.smalley.work@gmail.com> wrote: > > On Fri, Jul 26, 2024 at 1:50 PM Stephen Smalley > <stephen.smalley.work@gmail.com> wrote: > > > > On Thu, Jul 25, 2024 at 12:11 PM Vit Mojzis <vmojzis@redhat.com> wrote: > > > > > > Make sure that file context (all parts) and ownership of > > > files/directories in policy store does not change no matter which user > > > and under which context executes policy rebuild. > > > > > > Fixes: > > > # semodule -B > > > # ls -lZ /etc/selinux/targeted/contexts/files > > > > > > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 421397 Jul 11 09:57 file_contexts > > > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 593470 Jul 11 09:57 file_contexts.bin > > > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 14704 Jul 11 09:57 file_contexts.homedirs > > > -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 20289 Jul 11 09:57 file_contexts.homedirs.bin > > > > > > SELinux user changed from system_u to the user used to execute semodule > > > > > > # capsh --user=testuser --caps="cap_dac_override,cap_chown+eip" --addamb=cap_dac_override,cap_chown -- -c "semodule -B" > > > # ls -lZ /etc/selinux/targeted/contexts/files > > > > > > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 421397 Jul 19 09:10 file_contexts > > > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 593470 Jul 19 09:10 file_contexts.bin > > > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 14704 Jul 19 09:10 file_contexts.homedirs > > > -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 20289 Jul 19 09:10 file_contexts.homedirs.bin > > > > > > Both file context and ownership changed -- causes remote login > > > failures and other issues in some scenarios. > > > > > > Signed-off-by: Vit Mojzis <vmojzis@redhat.com> > > > > With the selinux/restorecon.h fix applied first, > > > > Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com> > > Ah, spoke too soon. The GitHub CI testing failed with this: > semanage_store.c: In function ‘semanage_setfiles’: > 520 semanage_store.c:3047:25: error: ignoring return value of ‘fchown’ > declared with attribute ‘warn_unused_result’ [-Werror=unused-result] > 521 3047 | fchown(fd, 0, 0); > 522 | ^~~~~~~~~~~~~~~~ Unfortunately, you can't just mark this as intentional, as per https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25509. Casting to void doesn't eliminate the warning. Saving the return value but not using it somewhere triggers another warning. Calling assert() if rc != 0 breaks make test in libsemanage. We don't have a handle here or in the immediate callers so can't just call ERR(). Changing it to: rc = fchown(fd, 0, 0); if (rc) fprintf(stderr, "Warning! Could not set ownership of %s to root\n",path); seems to solve the warning problem but is a bit ugly.
diff --git a/libsemanage/src/semanage_store.c b/libsemanage/src/semanage_store.c index 27c5d349..95596a93 100644 --- a/libsemanage/src/semanage_store.c +++ b/libsemanage/src/semanage_store.c @@ -36,6 +36,7 @@ typedef struct dbase_policydb dbase_t; #include "database_policydb.h" #include "handle.h" +#include <selinux/restorecon.h> #include <selinux/selinux.h> #include <sepol/policydb.h> #include <sepol/module.h> @@ -767,6 +768,7 @@ int semanage_copy_file(const char *src, const char *dst, mode_t mode, if (!retval && rename(tmp, dst) == -1) return -1; + semanage_setfiles(dst); out: errno = errsv; return retval; @@ -819,6 +821,8 @@ static int semanage_copy_dir_flags(const char *src, const char *dst, int flag) goto cleanup; } umask(mask); + + semanage_setfiles(dst); } for (i = 0; i < len; i++) { @@ -837,6 +841,7 @@ static int semanage_copy_dir_flags(const char *src, const char *dst, int flag) goto cleanup; } umask(mask); + semanage_setfiles(path2); } else if (S_ISREG(sb.st_mode) && flag == 1) { mask = umask(0077); if (semanage_copy_file(path, path2, sb.st_mode, @@ -938,6 +943,7 @@ int semanage_mkdir(semanage_handle_t *sh, const char *path) } umask(mask); + semanage_setfiles(path); } else { /* check that it really is a directory */ @@ -1614,16 +1620,19 @@ static int semanage_validate_and_compile_fcontexts(semanage_handle_t * sh) semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC)) != 0) { goto cleanup; } + semanage_setfiles(semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_BIN)); if (sefcontext_compile(sh, semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_LOCAL)) != 0) { goto cleanup; } + semanage_setfiles(semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_LOCAL_BIN)); if (sefcontext_compile(sh, semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_HOMEDIRS)) != 0) { goto cleanup; } + semanage_setfiles(semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_HOMEDIRS_BIN)); status = 0; cleanup: @@ -3018,3 +3027,25 @@ int semanage_nc_sort(semanage_handle_t * sh, const char *buf, size_t buf_len, return 0; } + +/* Make sure the file context and ownership of files in the policy + * store does not change */ +void semanage_setfiles(const char *path){ + struct stat sb; + int fd; + /* Fix the user and role portions of the context, ignore errors + * since this is not a critical operation */ + selinux_restorecon(path, SELINUX_RESTORECON_SET_SPECFILE_CTX | SELINUX_RESTORECON_IGNORE_NOENTRY); + + /* Make sure "path" is owned by root */ + if ((geteuid() != 0 || getegid() != 0) && + ((fd = open(path, O_RDONLY)) != -1)){ + /* Skip files with the SUID or SGID bit set -- abuse protection */ + if ((fstat(fd, &sb) != -1) && + !(S_ISREG(sb.st_mode) && + (sb.st_mode & (S_ISUID | S_ISGID)))) + fchown(fd, 0, 0); + + close(fd); + } +} diff --git a/libsemanage/src/semanage_store.h b/libsemanage/src/semanage_store.h index 1fc77da8..e21dadeb 100644 --- a/libsemanage/src/semanage_store.h +++ b/libsemanage/src/semanage_store.h @@ -124,6 +124,7 @@ int semanage_get_cil_paths(semanage_handle_t * sh, semanage_module_info_t *modin int semanage_get_active_modules(semanage_handle_t *sh, semanage_module_info_t **modinfo, int *num_modules); +void semanage_setfiles(const char *path); /* lock file routines */ int semanage_get_trans_lock(semanage_handle_t * sh);
Make sure that file context (all parts) and ownership of files/directories in policy store does not change no matter which user and under which context executes policy rebuild. Fixes: # semodule -B # ls -lZ /etc/selinux/targeted/contexts/files -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 421397 Jul 11 09:57 file_contexts -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 593470 Jul 11 09:57 file_contexts.bin -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 14704 Jul 11 09:57 file_contexts.homedirs -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 20289 Jul 11 09:57 file_contexts.homedirs.bin SELinux user changed from system_u to the user used to execute semodule # capsh --user=testuser --caps="cap_dac_override,cap_chown+eip" --addamb=cap_dac_override,cap_chown -- -c "semodule -B" # ls -lZ /etc/selinux/targeted/contexts/files -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 421397 Jul 19 09:10 file_contexts -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 593470 Jul 19 09:10 file_contexts.bin -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 14704 Jul 19 09:10 file_contexts.homedirs -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 20289 Jul 19 09:10 file_contexts.homedirs.bin Both file context and ownership changed -- causes remote login failures and other issues in some scenarios. Signed-off-by: Vit Mojzis <vmojzis@redhat.com> --- libsemanage/src/semanage_store.c | 31 +++++++++++++++++++++++++++++++ libsemanage/src/semanage_store.h | 1 + 2 files changed, 32 insertions(+)