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-rw-r--r--apt-pkg/acquire.cc51
-rw-r--r--apt-pkg/acquire.h2
2 files changed, 53 insertions, 0 deletions
diff --git a/apt-pkg/acquire.cc b/apt-pkg/acquire.cc
index f8b077367..cb32e8f2b 100644
--- a/apt-pkg/acquire.cc
+++ b/apt-pkg/acquire.cc
@@ -34,6 +34,7 @@
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
+#include <fcntl.h>
#include <pwd.h>
#include <grp.h>
#include <dirent.h>
@@ -446,8 +447,58 @@ void pkgAcquire::RunFds(fd_set *RSet,fd_set *WSet)
/* This runs the queues. It manages a select loop for all of the
Worker tasks. The workers interact with the queues and items to
manage the actual fetch. */
+static void CheckDropPrivsMustBeDisabled(pkgAcquire const &Fetcher)
+{
+ if(getuid() != 0)
+ return;
+
+ std::string SandboxUser = _config->Find("APT::Sandbox::User");
+ if (SandboxUser.empty())
+ return;
+
+ struct passwd const * const pw = getpwnam(SandboxUser.c_str());
+ if (pw == NULL)
+ return;
+
+ if (setegid(pw->pw_gid) != 0)
+ _error->Errno("setegid", "setegid %u failed", pw->pw_gid);
+ if (seteuid(pw->pw_uid) != 0)
+ _error->Errno("seteuid", "seteuid %u failed", pw->pw_uid);
+
+ bool dropPrivs = true;
+ for (pkgAcquire::ItemCIterator I = Fetcher.ItemsBegin();
+ I != Fetcher.ItemsEnd() && dropPrivs == true; ++I)
+ {
+ if ((*I)->DestFile.empty())
+ continue;
+
+ // we check directory instead of file as the file might or might not
+ // exist already as a link or not which complicates everything…
+ std::string dirname = flNotFile((*I)->DestFile);
+ if (DirectoryExists(dirname))
+ ;
+ else
+ continue; // assume it is created correctly by the acquire system
+
+ if (faccessat(AT_FDCWD, dirname.c_str(), R_OK | W_OK | X_OK, AT_EACCESS | AT_SYMLINK_NOFOLLOW) != 0)
+ {
+ dropPrivs = false;
+ _error->WarningE("pkgAcquire::Run", _("Can't drop privileges for downloading as file '%s' couldn't be accessed by user '%s'."),
+ (*I)->DestFile.c_str(), SandboxUser.c_str());
+ _config->Set("APT::Sandbox::User", "");
+ break;
+ }
+ }
+
+ if (seteuid(0) != 0)
+ _error->Errno("seteuid", "seteuid %u failed", 0);
+ if (setegid(0) != 0)
+ _error->Errno("setegid", "setegid %u failed", 0);
+}
pkgAcquire::RunResult pkgAcquire::Run(int PulseIntervall)
{
+ CheckDropPrivsMustBeDisabled(*this);
+
Running = true;
for (Queue *I = Queues; I != 0; I = I->Next)
diff --git a/apt-pkg/acquire.h b/apt-pkg/acquire.h
index 10025a6ef..3e5ca41cd 100644
--- a/apt-pkg/acquire.h
+++ b/apt-pkg/acquire.h
@@ -303,9 +303,11 @@ class pkgAcquire
/** \brief Get the head of the list of items. */
inline ItemIterator ItemsBegin() {return Items.begin();};
+ inline ItemCIterator ItemsBegin() const {return Items.begin();};
/** \brief Get the end iterator of the list of items. */
inline ItemIterator ItemsEnd() {return Items.end();};
+ inline ItemCIterator ItemsEnd() const {return Items.end();};
// Iterate over queued Item URIs
class UriIterator;