diff options
| -rw-r--r-- | archival/Config.in | 8 | ||||
| -rw-r--r-- | archival/libunarchive/data_extract_all.c | 21 | ||||
| -rw-r--r-- | archival/libunarchive/get_header_tar.c | 78 | ||||
| -rw-r--r-- | include/unarchive.h | 4 |
4 files changed, 108 insertions, 3 deletions
diff --git a/archival/Config.in b/archival/Config.in index c99896b47..deacc2822 100644 --- a/archival/Config.in +++ b/archival/Config.in @@ -289,6 +289,14 @@ config FEATURE_TAR_NOPRESERVE_TIME With this option busybox supports GNU tar -m (do not preserve time) option. +config FEATURE_TAR_SELINUX + bool "Support for extracting SELinux labels" + default n + depends on TAR && SELINUX + help + With this option busybox supports restoring SELinux labels + when extracting files from tar archives. + config UNCOMPRESS bool "uncompress" default n diff --git a/archival/libunarchive/data_extract_all.c b/archival/libunarchive/data_extract_all.c index 58b05335b..cc4894229 100644 --- a/archival/libunarchive/data_extract_all.c +++ b/archival/libunarchive/data_extract_all.c @@ -12,6 +12,17 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle) int dst_fd; int res; +#if ENABLE_FEATURE_TAR_SELINUX + char *sctx = archive_handle->tar__next_file_sctx; + if (!sctx) + sctx = archive_handle->tar__global_sctx; + if (sctx) { /* setfscreatecon is 4 syscalls, avoid if possible */ + setfscreatecon(sctx); + free(archive_handle->tar__next_file_sctx); + archive_handle->tar__next_file_sctx = NULL; + } +#endif + if (archive_handle->ah_flags & ARCHIVE_CREATE_LEADING_DIRS) { char *slash = strrchr(file_header->name, '/'); if (slash) { @@ -45,7 +56,7 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle) "same age file exists", file_header->name); } data_skip(archive_handle); - return; + goto ret; } else if ((unlink(file_header->name) == -1) && (errno != EISDIR)) { bb_perror_msg_and_die("can't remove old file %s", @@ -158,4 +169,12 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle) utimes(file_header->name, t); } } + + ret: ; +#if ENABLE_FEATURE_TAR_SELINUX + if (sctx) { + /* reset the context after creating an entry */ + setfscreatecon(NULL); + } +#endif } diff --git a/archival/libunarchive/get_header_tar.c b/archival/libunarchive/get_header_tar.c index d5b86ff5c..cf0b9ab02 100644 --- a/archival/libunarchive/get_header_tar.c +++ b/archival/libunarchive/get_header_tar.c @@ -103,6 +103,63 @@ static unsigned long long getOctal(char *str, int len) } #define GET_OCTAL(a) getOctal((a), sizeof(a)) +#if ENABLE_FEATURE_TAR_SELINUX +/* Scan a PAX header for SELinux contexts, via "RHT.security.selinux" keyword. + * This is what Red Hat's patched version of tar uses. + */ +# define SELINUX_CONTEXT_KEYWORD "RHT.security.selinux" +static char *get_selinux_sctx_from_pax_hdr(archive_handle_t *archive_handle, unsigned sz) +{ + char *buf, *p; + char *result; + + p = buf = xmalloc(sz + 1); + /* prevent bb_strtou from running off the buffer */ + buf[sz] = '\0'; + xread(archive_handle->src_fd, buf, sz); + archive_handle->offset += sz; + + result = NULL; + while (sz != 0) { + char *end, *value; + unsigned len; + + /* Every record has this format: "LEN NAME=VALUE\n" */ + len = bb_strtou(p, &end, 10); + /* expect errno to be EINVAL, because the character + * following the digits should be a space + */ + p += len; + sz -= len; + if ((int)sz < 0 + || len == 0 + || errno != EINVAL + || *end != ' ' + ) { + bb_error_msg("malformed extended header, skipped"); + // More verbose version: + //bb_error_msg("malformed extended header at %"OFF_FMT"d, skipped", + // archive_handle->offset - (sz + len)); + break; + } + /* overwrite the terminating newline with NUL + * (we do not bother to check that it *was* a newline) + */ + p[-1] = '\0'; + /* Is it selinux security context? */ + value = end + 1; + if (strncmp(value, SELINUX_CONTEXT_KEYWORD"=", sizeof(SELINUX_CONTEXT_KEYWORD"=") - 1) == 0) { + value += sizeof(SELINUX_CONTEXT_KEYWORD"=") - 1; + result = xstrdup(value); + break; + } + } + + free(buf); + return result; +} +#endif + void BUG_tar_header_size(void); char FAST_FUNC get_header_tar(archive_handle_t *archive_handle) { @@ -150,7 +207,7 @@ char FAST_FUNC get_header_tar(archive_handle_t *archive_handle) if (sizeof(tar) != 512) BUG_tar_header_size(); -#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS +#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS || ENABLE_FEATURE_TAR_SELINUX again: #endif /* Align header */ @@ -392,8 +449,13 @@ char FAST_FUNC get_header_tar(archive_handle_t *archive_handle) case 'S': /* Sparse file */ case 'V': /* Volume header */ #endif +#if !ENABLE_FEATURE_TAR_SELINUX case 'g': /* pax global header */ - case 'x': { /* pax extended header */ + case 'x': /* pax extended header */ +#else + skip_ext_hdr: +#endif + { off_t sz; bb_error_msg("warning: skipping header '%c'", tar.typeflag); sz = (file_header->size + 511) & ~(off_t)511; @@ -404,6 +466,18 @@ char FAST_FUNC get_header_tar(archive_handle_t *archive_handle) /* return get_header_tar(archive_handle); */ goto again_after_align; } +#if ENABLE_FEATURE_TAR_SELINUX + case 'g': /* pax global header */ + case 'x': { /* pax extended header */ + char **pp; + if ((uoff_t)file_header->size > 0xfffff) /* paranoia */ + goto skip_ext_hdr; + pp = (tar.typeflag == 'g') ? &archive_handle->tar__global_sctx : &archive_handle->tar__next_file_sctx; + free(*pp); + *pp = get_selinux_sctx_from_pax_hdr(archive_handle, file_header->size); + goto again; + } +#endif default: bb_error_msg_and_die("unknown typeflag: 0x%x", tar.typeflag); } diff --git a/include/unarchive.h b/include/unarchive.h index 92ebd6565..a834816ba 100644 --- a/include/unarchive.h +++ b/include/unarchive.h @@ -59,6 +59,10 @@ typedef struct archive_handle_t { char* tar__longname; char* tar__linkname; # endif +# if ENABLE_FEATURE_TAR_SELINUX + char* tar__global_sctx; + char* tar__next_file_sctx; +# endif #endif #if ENABLE_CPIO || ENABLE_RPM2CPIO || ENABLE_RPM uoff_t cpio__blocks; |