[PATCH] uml: handle unusual results from find_tempdir.

[Jim Meyering]

An alternative: make find_tempdir set tempdir to default_tempdir
upon malloc failure.

* arch/um/os-Linux/mem.c (make_tempfile): Handle NULL tempdir.
Don't let a long tempdir (e.g., via TMPDIR) provoke heap corruption.

Signed-off-by: Jim Meyering <meyering@xxxxxxxxxx>
---
 arch/um/os-Linux/mem.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/arch/um/os-Linux/mem.c b/arch/um/os-Linux/mem.c
index e114d09..1458385 100644
--- a/arch/um/os-Linux/mem.c
+++ b/arch/um/os-Linux/mem.c
@@ -176,6 +176,9 @@ int __init make_tempfile(const char *template, char **out_tempname,
 	  return -1;

 	find_tempdir();
+	if (tempdir == NULL || strlen(tempdir) >= MAXPATHLEN)
+	  return -1;
+
 	if (template[0] != '/')
 		strcpy(tempname, tempdir);
 	else
--
1.5.4.19.gd3dfd
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