[Libguestfs] [PATCH 12/13] Coverity: Don't return freed pointers from command* along error path.

If the external command failed to run, we could free up the allocated *stdoutput and *stderror pointers, but then return those freed pointers to the caller. The caller usually tries to print and free *stderror, so this is a serious error. Instead, return *stdoutput as NULL, and *stderror pointing to a generic error message. --- daemon/guestfsd.c | 16 ++++++++++++++-- 1 files changed, 14 insertions(+), 2 deletions(-) diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c index ceadfdb..116a6b9 100644 --- a/daemon/guestfsd.c +++ b/daemon/guestfsd.c @@ -779,8 +779,20 @@ commandrvf (char **stdoutput, char **stderror, int flags, perror ("select"); quit: - if (stdoutput) free (*stdoutput); - if (stderror) free (*stderror); + if (stdoutput) { + free (*stdoutput); + *stdoutput = NULL; + } + if (stderror) { + free (*stderror); + /* Need to return non-NULL *stderror here since most callers + * will try to print and then free the err string. + * Unfortunately recovery from strdup failure here is not + * possible. + */ + *stderror = strdup ("error running external command, " + "see debug output for details"); + } close (so_fd[0]); close (se_fd[0]); waitpid (pid, NULL, 0); -- 1.7.5.1