don't change owner/perms/times through file:// symlinks

If we have files in partial/ from a previous invocation or similar such
those could be symlinks created by file:// sources. The code is
expecting only real files through and happily changes owner,
modification times and permission on the file the symlink points to
which tend to be files we have no business in touching in this way.
Permissions of symlinks shouldn't be changed, changing owner is usually
pointless to, but just to be sure we pick the easy way out and use
lchown, check for symlinks before chmod/utimes.

Reported-By: Mattia Rizzolo on IRC
(cherry picked from commit 3465138575e1fd0d5892d9b6be1ae232eb873460)

7 files changed, 60 insertions, 23 deletions

diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
index 09dce4123..ef88f6fdd 100644
--- a/apt-pkg/contrib/fileutl.cc
+++ b/apt-pkg/contrib/fileutl.cc
@@ -916,9 +916,12 @@ bool ChangeOwnerAndPermissionOfFile(char const * const requester, char const * c
       // ensure the file is owned by root and has good permissions
       struct passwd const * const pw = getpwnam(user);
       struct group const * const gr = getgrnam(group);
-      if (pw != NULL && gr != NULL && chown(file, pw->pw_uid, gr->gr_gid) != 0)
+      if (pw != NULL && gr != NULL && lchown(file, pw->pw_uid, gr->gr_gid) != 0)
 	 Res &= _error->WarningE(requester, "chown to %s:%s of file %s failed", user, group, file);
    }
+   struct stat Buf;
+   if (lstat(file, &Buf) != 0 || S_ISLNK(Buf.st_mode))
+      return Res;
    if (chmod(file, mode) != 0)
       Res &= _error->WarningE(requester, "chmod 0%o of file %s failed", mode, file);
    return Res;
diff --git a/methods/aptmethod.h b/methods/aptmethod.h
index f8a68c92b..dd488fe6f 100644
--- a/methods/aptmethod.h
+++ b/methods/aptmethod.h
@@ -3,9 +3,17 @@
 
 #include <apt-pkg/acquire-method.h>
 #include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
 
 #include <string>
 
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+
 class aptMethod : public pkgAcqMethod
 {
    char const * const Binary;
@@ -42,6 +50,29 @@ public:
       va_end(args);
    }
 
+   bool TransferModificationTimes(char const * const From, char const * const To, time_t &LastModified)
+   {
+      if (strcmp(To, "/dev/null") == 0)
+	 return true;
+
+      struct stat Buf2;
+      if (lstat(To, &Buf2) != 0 || S_ISLNK(Buf2.st_mode))
+	 return true;
+
+      struct stat Buf;
+      if (stat(From, &Buf) != 0)
+	 return _error->Errno("stat",_("Failed to stat"));
+
+      // we don't use utimensat here for compatibility reasons: #738567
+      struct timeval times[2];
+      times[0].tv_sec = Buf.st_atime;
+      LastModified = times[1].tv_sec = Buf.st_mtime;
+      times[0].tv_usec = times[1].tv_usec = 0;
+      if (utimes(To, times) != 0)
+	 return _error->Errno("utimes",_("Failed to set modification time"));
+      return true;
+   }
+
    aptMethod(char const * const Binary, char const * const Ver, unsigned long const Flags) :
       pkgAcqMethod(Ver, Flags), Binary(Binary)
    {}
diff --git a/methods/copy.cc b/methods/copy.cc
index e515b2def..49b1bae5e 100644
--- a/methods/copy.cc
+++ b/methods/copy.cc
@@ -79,13 +79,8 @@ bool CopyMethod::Fetch(FetchItem *Itm)
    From.Close();
    To.Close();
 
-   // Transfer the modification times
-   struct timeval times[2];
-   times[0].tv_sec = Buf.st_atime;
-   times[1].tv_sec = Buf.st_mtime;
-   times[0].tv_usec = times[1].tv_usec = 0;
-   if (utimes(Res.Filename.c_str(), times) != 0)
-      return _error->Errno("utimes",_("Failed to set modification time"));
+   if (TransferModificationTimes(File.c_str(), Res.Filename.c_str(), Res.LastModified) == false)
+      return false;
 
    CalculateHashes(Itm, Res);
    URIDone(Res);
diff --git a/methods/store.cc b/methods/store.cc
index 2ad0f0177..515c63387 100644
--- a/methods/store.cc
+++ b/methods/store.cc
@@ -127,20 +127,8 @@ bool StoreMethod::Fetch(FetchItem *Itm)					/*{{{*/
    if (Failed == true)
       return false;
 
-   // Transfer the modification times
-   if (Itm->DestFile != "/dev/null")
-   {
-      struct stat Buf;
-      if (stat(Path.c_str(),&Buf) != 0)
-	 return _error->Errno("stat",_("Failed to stat"));
-
-      struct timeval times[2];
-      times[0].tv_sec = Buf.st_atime;
-      Res.LastModified = times[1].tv_sec = Buf.st_mtime;
-      times[0].tv_usec = times[1].tv_usec = 0;
-      if (utimes(Itm->DestFile.c_str(), times) != 0)
-	 return _error->Errno("utimes",_("Failed to set modification time"));
-   }
+   if (TransferModificationTimes(Path.c_str(), Itm->DestFile.c_str(), Res.LastModified) == false)
+      return false;
 
    // Return a Done response
    Res.TakeHashes(Hash);
diff --git a/test/integration/framework b/test/integration/framework
index ca0a3b5de..7fdf21bed 100644
--- a/test/integration/framework
+++ b/test/integration/framework
@@ -1862,6 +1862,11 @@ pause() {
 	read IGNORE
 }
 
+logcurrentarchivedirectory() {
+	find "${TMPWORKINGDIRECTORY}/aptarchive/dists" -type f | while read line; do
+		stat --format '%U:%G:%a:%n' "$line"
+	done | sort > "${TMPWORKINGDIRECTORY}/rootdir/var/log/aptgetupdate.before.lst"
+}
 listcurrentlistsdirectory() {
 	{
 		find rootdir/var/lib/apt/lists -maxdepth 1 -type d | while read line; do
@@ -1940,6 +1945,10 @@ aptautotest_aptget_update() {
 		# failure cases can retain partial files and such
 		testempty find "${TMPWORKINGDIRECTORY}/rootdir/var/lib/apt/lists/partial" -mindepth 1 ! \( -name 'lock' -o -name '*.FAILED' \)
 	fi
+	if [ -s "${TMPWORKINGDIRECTORY}/rootdir/var/log/aptgetupdate.before.lst" ]; then
+		testfileequal "${TMPWORKINGDIRECTORY}/rootdir/var/log/aptgetupdate.before.lst" \
+			"$(find "${TMPWORKINGDIRECTORY}/aptarchive/dists" -type f | while read line; do stat --format '%U:%G:%a:%n' "$line"; done | sort)"
+	fi
 }
 aptautotest_apt_update() { aptautotest_aptget_update "$@"; }
 aptautotest_aptcdrom_add() { aptautotest_aptget_update "$@"; }
diff --git a/test/integration/test-apt-update-file b/test/integration/test-apt-update-file
index 20f604695..8da4ec35b 100755
--- a/test/integration/test-apt-update-file
+++ b/test/integration/test-apt-update-file
@@ -18,6 +18,7 @@ insertpackage 'unstable' 'bar' 'amd64' '1'
 insertsource 'unstable' 'foo' 'all' '1'
 
 setupaptarchive --no-update
+logcurrentarchivedirectory
 
 # ensure the archive is not writable
 addtrap 'prefix' 'chmod 755 aptarchive/dists/unstable/main/binary-all;'
@@ -37,8 +38,11 @@ if [ "$(id -u)" = '0' ]; then
 	rm -rf rootdir/var/lib/apt/lists
 	chmod 500 aptarchive/dists/
 	testsuccesswithnotice aptget update
-	exit
+	chmod 755 aptarchive/dists/
+else
+	testsuccess aptget update
 fi
+mv rootdir/var/lib/apt/lists/_* rootdir/var/lib/apt/lists/partial
 chmod 555 aptarchive/dists/unstable/main/binary-all
 testsuccess aptget update -o Debug::pkgAcquire::Worker=1
 cp -a rootdir/tmp/testsuccess.output rootdir/tmp/update.output
diff --git a/test/integration/test-apt-update-ims b/test/integration/test-apt-update-ims
index 241bf383b..5a44911a6 100755
--- a/test/integration/test-apt-update-ims
+++ b/test/integration/test-apt-update-ims
@@ -11,6 +11,7 @@ insertpackage 'unstable' 'unrelated2' 'amd64' '0.5~squeeze1'
 insertsource 'unstable' 'unrelated' 'all' '0.5~squeeze1'
 
 setupaptarchive --no-update
+logcurrentarchivedirectory
 changetowebserver
 
 runtest() {
@@ -70,6 +71,7 @@ EXPECT="Ign:1 http://localhost:${APTHTTPPORT} unstable InRelease
 Hit:2 http://localhost:${APTHTTPPORT} unstable Release
 Reading package lists..."
 find aptarchive -name 'InRelease' -delete
+logcurrentarchivedirectory
 echo 'Acquire::GzipIndexes "0";' > rootdir/etc/apt/apt.conf.d/02compressindex
 runtest
 echo 'Acquire::GzipIndexes "1";' > rootdir/etc/apt/apt.conf.d/02compressindex
@@ -86,6 +88,7 @@ W: The repository 'http://localhost:${APTHTTPPORT} unstable Release' is not sign
 N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
 N: See apt-secure(8) manpage for repository creation and user configuration details."
 find aptarchive -name 'Release.gpg' -delete
+logcurrentarchivedirectory
 echo 'Acquire::GzipIndexes "0";' > rootdir/etc/apt/apt.conf.d/02compressindex
 runtest 'warning'
 echo 'Acquire::GzipIndexes "1";' > rootdir/etc/apt/apt.conf.d/02compressindex
@@ -98,6 +101,7 @@ find aptarchive -name '*Release' -exec sed -i \
 	-e '/^Valid-Until: / d' -e "/^Date: / a\
 Valid-Until: $(date -d '-1 weeks' '+%a, %d %b %Y %H:%M:%S %Z')" '{}' \;
 signreleasefiles
+logcurrentarchivedirectory
 
 msgmsg 'expired InRelease'
 EXPECT="Hit:1 http://localhost:${APTHTTPPORT} unstable InRelease
@@ -115,6 +119,7 @@ Hit:2 http://localhost:${APTHTTPPORT} unstable Release
 Reading package lists...
 E: Release file for http://localhost:${APTHTTPPORT}/dists/unstable/Release is expired (invalid since). Updates for this repository will not be applied."
 find aptarchive -name 'InRelease' -delete
+logcurrentarchivedirectory
 echo 'Acquire::GzipIndexes "0";' > rootdir/etc/apt/apt.conf.d/02compressindex
 runtest 'failure'
 echo 'Acquire::GzipIndexes "1";' > rootdir/etc/apt/apt.conf.d/02compressindex
@@ -132,6 +137,7 @@ N: Data from such a repository can't be authenticated and is therefore potential
 N: See apt-secure(8) manpage for repository creation and user configuration details.
 E: Release file for http://localhost:${APTHTTPPORT}/dists/unstable/Release is expired (invalid since). Updates for this repository will not be applied."
 find aptarchive -name 'Release.gpg' -delete
+logcurrentarchivedirectory
 echo 'Acquire::GzipIndexes "0";' > rootdir/etc/apt/apt.conf.d/02compressindex
 runtest 'failure' 'warning'
 echo 'Acquire::GzipIndexes "1";' > rootdir/etc/apt/apt.conf.d/02compressindex
@@ -176,6 +182,7 @@ W: The repository 'http://localhost:${APTHTTPPORT} unstable Release' does not ha
 N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
 N: See apt-secure(8) manpage for repository creation and user configuration details."
 find aptarchive -name '*Release*' -delete
+logcurrentarchivedirectory
 echo 'Acquire::GzipIndexes "0";
 Acquire::PDiffs "0";' > rootdir/etc/apt/apt.conf.d/02compressindex
 runtest 'warning'