On Mon, 2009-08-24 at 10:57 -0400, Chris PeBenito wrote: > On Mon, 2009-08-24 at 10:04 -0400, Stephen Smalley wrote: > > On Mon, 2009-08-24 at 09:54 -0400, Chris PeBenito wrote: > > > I took the current release of libsemanage and added the patch to add a > > > bzip blocksize option[1]. The modules in my store were already > > > compressed with the stock release. I put bzip-blocksize=0 in my > > > semanage.conf and I do semodule -B and get: > > > > > > libsepol.module_package_read_offsets: wrong magic number for module > > > package: expected 0xf97cff8f, got 0x39685a42 (No such file or > > > directory). > > > libsemanage.semanage_load_module: Error while reading from module > > > file /etc/selinux/strict/modules/tmp/modules/apm.pp. (No such file or > > > directory). > > > semodule: Failed! > > > > > > If I do semodule -l, it will also get the magic number error. If I > > > remove the blocksize option, it works again. I was able to reinsert all > > > of the modules to get it working again with the blocksize 0 option. > > > > > > [1] http://userspace.selinuxproject.org/trac/changeset/ee9827000137fed2d3300124115fc1572acafe2f > > > > Yes, that's what I would expect. The expectation is that either one > > would set that option before installing the policy for the first time, > > or that one completely re-installs the policy after setting that option. > > Can we have a little better handling of this case? I don't mind > reinstalling the policy, but the error messages aren't helpful. In > addition, with semodule -l being broken, I have to look into the module > store to see what modules are installed or guess. Seems like it is just as easy to just support pre-existing compressed modules, see below. Explicitly probe for the bzip2 magic string prefix and fall through to BZ2_bzReadOpen() if the module is bzipped even if bzip-blocksize=0. Thus bzip-blocksize=0 will prevent any further compression of subsequently installed/updated modules, but will continue to function with existing compressed modules. Signed-off-by: Stephen Smalley <sds@xxxxxxxxxxxxx> --- libsemanage/src/direct_api.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/libsemanage/src/direct_api.c b/libsemanage/src/direct_api.c index d563841..068061f 100644 --- a/libsemanage/src/direct_api.c +++ b/libsemanage/src/direct_api.c @@ -452,6 +452,9 @@ static ssize_t bzip(semanage_handle_t *sh, const char *filename, char *data, return total; } +#define BZ2_MAGICSTR "BZh" +#define BZ2_MAGICLEN (sizeof(BZ2_MAGICSTR)-1) + /* bunzip() a file to '*data', returning the total number of uncompressed bytes * in the file. Returns -1 if file could not be decompressed. */ ssize_t bunzip(semanage_handle_t *sh, FILE *f, char **data) @@ -463,8 +466,13 @@ ssize_t bunzip(semanage_handle_t *sh, FILE *f, char **data) int bzerror; size_t total=0; - if (!sh->conf->bzip_blocksize) - return -1; + if (!sh->conf->bzip_blocksize) { + bzerror = fread(buf, 1, BZ2_MAGICLEN, f); + rewind(f); + if ((bzerror != BZ2_MAGICLEN) || memcmp(buf, BZ2_MAGICSTR, BZ2_MAGICLEN)) + return -1; + /* fall through */ + } b = BZ2_bzReadOpen ( &bzerror, f, 0, sh->conf->bzip_small, NULL, 0 ); if ( bzerror != BZ_OK ) { -- Stephen Smalley National Security Agency -- This message was distributed to subscribers of the selinux mailing list. If you no longer wish to subscribe, send mail to majordomo@xxxxxxxxxxxxx with the words "unsubscribe selinux" without quotes as the message.
