From 52f19bad2e4a3d5c7599df9afd5e3cd675ecac8c Mon Sep 17 00:00:00 2001 From: Vit Mojzis Date: Mon, 29 Jul 2024 13:26:45 +0200 Subject: [PATCH] libsemanage: Preserve file context and ownership in policy store 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 Acked-by: Stephen Smalley --- libsemanage/src/semanage_store.c | 32 ++++++++++++++++++++++++++++++++ libsemanage/src/semanage_store.h | 1 + 2 files changed, 33 insertions(+) diff --git a/libsemanage/src/semanage_store.c b/libsemanage/src/semanage_store.c index 1fff667d..52cc72d7 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 #include #include #include @@ -763,6 +764,7 @@ 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; @@ -801,6 +803,8 @@ 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++) { @@ -819,6 +823,7 @@ 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, @@ -920,6 +925,7 @@ int semanage_mkdir(semanage_handle_t *sh, const char *path) } umask(mask); + semanage_setfiles(path); } else { /* check that it really is a directory */ @@ -1597,16 +1603,19 @@ 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: @@ -3001,3 +3010,26 @@ 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) == -1)) + fprintf(stderr, "Warning! Could not set ownership of %s to root\n", path); + + 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