diff options
author | J. Tang <tang@jtang.org> | 2010-03-19 16:48:51 +0300 |
---|---|---|
committer | Denys Vlasenko <vda.linux@googlemail.com> | 2010-03-19 16:48:51 +0300 |
commit | 77a2c51e79eb54c8f5cc8903465223cbac6e8d50 (patch) | |
tree | 932aff055f4e16da85fe2dbb0c02404407077799 /archival/libunarchive/get_header_tar.c | |
parent | bcda0042e2313d65a835b874c78bf215d743a844 (diff) |
tar: optional support for restoring selinux context
function old new delta
get_header_tar 1690 1976 +286
data_extract_all 821 881 +60
.rodata 151446 151503 +57
get_header_cpio 1044 1077 +33
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/0 up/down: 436/0) Total: 436 bytes
Signed-off-by: J. Tang <tang@jtang.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'archival/libunarchive/get_header_tar.c')
-rw-r--r-- | archival/libunarchive/get_header_tar.c | 78 |
1 files changed, 76 insertions, 2 deletions
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); } |