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authorMichael Vogt <mvo@ubuntu.com>2014-10-06 17:42:39 +0200
committerMichael Vogt <mvo@ubuntu.com>2014-10-06 17:42:39 +0200
commita2d40703e4a5590a689ace4466f92e590434944d (patch)
tree5e878fcc11eb94d96c65940ef3d30e922f217950 /apt-pkg/contrib/fileutl.cc
parentffd2dd93a640b47663ebdccc4fda00b426b3db71 (diff)
parent00a06b8eb82cf930511fc003bd16d7034e5a0cb5 (diff)
make http size check work
Diffstat (limited to 'apt-pkg/contrib/fileutl.cc')
-rw-r--r--apt-pkg/contrib/fileutl.cc107
1 files changed, 101 insertions, 6 deletions
diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
index 02b30dc1f..df409fa36 100644
--- a/apt-pkg/contrib/fileutl.cc
+++ b/apt-pkg/contrib/fileutl.cc
@@ -47,6 +47,8 @@
#include <signal.h>
#include <errno.h>
#include <glob.h>
+#include <pwd.h>
+#include <grp.h>
#include <set>
#include <algorithm>
@@ -63,6 +65,10 @@
#include <endian.h>
#include <stdint.h>
+#if __gnu_linux__
+#include <sys/prctl.h>
+#endif
+
#include <apti18n.h>
/*}}}*/
@@ -890,7 +896,7 @@ class FileFdPrivate { /*{{{*/
bool eof;
bool compressing;
- LZMAFILE() : file(NULL), eof(false), compressing(false) {}
+ LZMAFILE() : file(NULL), eof(false), compressing(false) { buffer[0] = '\0'; }
~LZMAFILE() {
if (compressing == true)
{
@@ -1278,7 +1284,8 @@ bool FileFd::OpenInternDescriptor(unsigned int const Mode, APT::Configuration::C
if (d->lzma == NULL)
d->lzma = new FileFdPrivate::LZMAFILE;
d->lzma->file = (FILE*) compress_struct;
- d->lzma->stream = LZMA_STREAM_INIT;
+ lzma_stream tmp_stream = LZMA_STREAM_INIT;
+ d->lzma->stream = tmp_stream;
if ((Mode & ReadWrite) == ReadWrite)
return FileFdError("ReadWrite mode is not supported for file %s", FileName.c_str());
@@ -1834,7 +1841,8 @@ static bool StatFileFd(char const * const msg, int const iFd, std::string const
// higher-level code will generate more meaningful messages,
// even translated this would be meaningless for users
return _error->Errno("fstat", "Unable to determine %s for fd %i", msg, iFd);
- ispipe = S_ISFIFO(Buf.st_mode);
+ if (FileName.empty() == false)
+ ispipe = S_ISFIFO(Buf.st_mode);
}
// for compressor pipes st_size is undefined and at 'best' zero
@@ -2118,10 +2126,8 @@ bool Popen(const char* Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode)
int Pipe[2] = {-1, -1};
if(pipe(Pipe) != 0)
- {
return _error->Errno("pipe", _("Failed to create subprocess IPC"));
- return NULL;
- }
+
std::set<int> keep_fds;
keep_fds.insert(Pipe[0]);
keep_fds.insert(Pipe[1]);
@@ -2164,3 +2170,92 @@ bool Popen(const char* Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode)
return true;
}
+
+bool DropPrivs()
+{
+ // uid will be 0 in the end, but gid might be different anyway
+ uid_t old_uid = getuid();
+ gid_t old_gid = getgid();
+
+ if (old_uid != 0)
+ return true;
+ if(_config->FindB("Debug::NoDropPrivs", false) == true)
+ return true;
+
+ const std::string toUser = _config->Find("APT::Sandbox::User", "_apt");
+ struct passwd *pw = getpwnam(toUser.c_str());
+ if (pw == NULL)
+ return _error->Error("No user %s, can not drop rights", toUser.c_str());
+
+#if __gnu_linux__
+ // see prctl(2), needs linux3.5
+ int ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0,0, 0);
+ if(ret < 0)
+ _error->Warning("PR_SET_NO_NEW_PRIVS failed with %i", ret);
+#endif
+ // Do not change the order here, it might break things
+ if (setgroups(1, &pw->pw_gid))
+ return _error->Errno("setgroups", "Failed to setgroups");
+
+ if (setegid(pw->pw_gid) != 0)
+ return _error->Errno("setegid", "Failed to setegid");
+
+ if (setgid(pw->pw_gid) != 0)
+ return _error->Errno("setgid", "Failed to setgid");
+
+ if (setuid(pw->pw_uid) != 0)
+ return _error->Errno("setuid", "Failed to setuid");
+
+ // the seteuid() is probably uneeded (at least thats what the linux
+ // man-page says about setuid(2)) but we cargo culted it anyway
+ if (seteuid(pw->pw_uid) != 0)
+ return _error->Errno("seteuid", "Failed to seteuid");
+
+ // Verify that the user has only a single group, and the correct one
+ gid_t groups[1];
+ if (getgroups(1, groups) != 1)
+ return _error->Errno("getgroups", "Could not get new groups");
+ if (groups[0] != pw->pw_gid)
+ return _error->Error("Could not switch group");
+
+ // Verify that gid, egid, uid, and euid changed
+ if (getgid() != pw->pw_gid)
+ return _error->Error("Could not switch group");
+ if (getegid() != pw->pw_gid)
+ return _error->Error("Could not switch effective group");
+ if (getuid() != pw->pw_uid)
+ return _error->Error("Could not switch user");
+ if (geteuid() != pw->pw_uid)
+ return _error->Error("Could not switch effective user");
+
+#ifdef HAVE_GETRESUID
+ // verify that the saved set-user-id was changed as well
+ uid_t ruid = 0;
+ uid_t euid = 0;
+ uid_t suid = 0;
+ if (getresuid(&ruid, &euid, &suid))
+ return _error->Errno("getresuid", "Could not get saved set-user-ID");
+ if (suid != pw->pw_uid)
+ return _error->Error("Could not switch saved set-user-ID");
+#endif
+
+#ifdef HAVE_GETRESGID
+ // verify that the saved set-group-id was changed as well
+ gid_t rgid = 0;
+ gid_t egid = 0;
+ gid_t sgid = 0;
+ if (getresgid(&rgid, &egid, &sgid))
+ return _error->Errno("getresuid", "Could not get saved set-group-ID");
+ if (sgid != pw->pw_gid)
+ return _error->Error("Could not switch saved set-group-ID");
+#endif
+
+ // Check that uid and gid changes do not work anymore
+ if (pw->pw_gid != old_gid && (setgid(old_gid) != -1 || setegid(old_gid) != -1))
+ return _error->Error("Could restore a gid to root, privilege dropping did not work");
+
+ if (pw->pw_uid != old_uid && (setuid(old_uid) != -1 || seteuid(old_uid) != -1))
+ return _error->Error("Could restore a uid to root, privilege dropping did not work");
+
+ return true;
+}