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authorLudovic Courtès <ludo@gnu.org>2015-05-11 22:21:31 +0200
committerLudovic Courtès <ludo@gnu.org>2015-05-11 23:01:20 +0200
commit1303a4a4517260def862ce7fe97e6b28dd8005e1 (patch)
tree1aa55bda57bd4ff8f951bf4aa5a84045eae220f5 /nix/libutil
parent2320ea1a51ce707ca19967f50e6fbedefafe14c4 (diff)
downloadpatches-1303a4a4517260def862ce7fe97e6b28dd8005e1.tar
patches-1303a4a4517260def862ce7fe97e6b28dd8005e1.tar.gz
daemon: Fix possible use-after-free.
This is essentially a backport of <https://github.com/NixOS/nix/commit/f52b6c944e90b3e35925122779175705fdc02e12> by Eelco Dolstra <eelco.dolstra@logicblox.com>. The use-after-free bug would typically manifest when building with GCC 5.1.
Diffstat (limited to 'nix/libutil')
-rw-r--r--nix/libutil/util.cc20
-rw-r--r--nix/libutil/util.hh5
2 files changed, 19 insertions, 6 deletions
diff --git a/nix/libutil/util.cc b/nix/libutil/util.cc
index 846674a29d..024cea83d1 100644
--- a/nix/libutil/util.cc
+++ b/nix/libutil/util.cc
@@ -852,16 +852,20 @@ void killUser(uid_t uid)
//////////////////////////////////////////////////////////////////////
+std::vector<const char *> stringsToCharPtrs(const Strings & ss)
+{
+ std::vector<const char *> res;
+ foreach (Strings::const_iterator, i, ss)
+ res.push_back(i->c_str());
+ res.push_back(0);
+ return res;
+}
+
+
string runProgram(Path program, bool searchPath, const Strings & args)
{
checkInterrupt();
- std::vector<const char *> cargs; /* careful with c_str()! */
- cargs.push_back(program.c_str());
- for (Strings::const_iterator i = args.begin(); i != args.end(); ++i)
- cargs.push_back(i->c_str());
- cargs.push_back(0);
-
/* Create a pipe. */
Pipe pipe;
pipe.create();
@@ -880,6 +884,10 @@ string runProgram(Path program, bool searchPath, const Strings & args)
if (dup2(pipe.writeSide, STDOUT_FILENO) == -1)
throw SysError("dupping stdout");
+ Strings args_(args);
+ args_.push_front(program);
+ auto cargs = stringsToCharPtrs(args_);
+
if (searchPath)
execvp(program.c_str(), (char * *) &cargs[0]);
else
diff --git a/nix/libutil/util.hh b/nix/libutil/util.hh
index ce2d77c19a..a70981877b 100644
--- a/nix/libutil/util.hh
+++ b/nix/libutil/util.hh
@@ -257,6 +257,11 @@ void killUser(uid_t uid);
string runProgram(Path program, bool searchPath = false,
const Strings & args = Strings());
+/* Convert a list of strings to a null-terminated vector of char
+ *'s. The result must not be accessed beyond the lifetime of the
+ list of strings. */
+std::vector<const char *> stringsToCharPtrs(const Strings & ss);
+
/* Close all file descriptors except stdin, stdout, stderr, and those
listed in the given set. Good practice in child processes. */
void closeMostFDs(const set<int> & exceptions);