[PATCH] Cygwin: exec: check execute bit prior to evaluating script
Corinna Vinschen
corinna@vinschen.de
Tue Aug 6 08:54:00 GMT 2019
From: Corinna Vinschen <corinna-cygwin@cygwin.com>
When the exec family of functions is called for a script-like
file, the av::setup function handles the exec[vl]p case as
well. The execve case for files not starting with a she-bang
is handled first by returning ENOEXEC. Only after that, the
file's executability is checked.
This leads to the problem that ENOEXEC is returned for non-executable
files as well. A calling shell interprets this as a file it should try
to run as script. This is not desired for non-executable files.
Fix this problem by checking the file for executability first. Only
after that, follow the other potential code paths.
---
winsup/cygwin/spawn.cc | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/winsup/cygwin/spawn.cc b/winsup/cygwin/spawn.cc
index 7f7af4449da1..d95772802f8f 100644
--- a/winsup/cygwin/spawn.cc
+++ b/winsup/cygwin/spawn.cc
@@ -1172,6 +1172,12 @@ av::setup (const char *prog_arg, path_conv& real_path, const char *ext,
}
UnmapViewOfFile (buf);
just_shell:
+ /* Check if script is executable. Otherwise we start non-executable
+ scripts successfully, which is incorrect behaviour. */
+ if (real_path.has_acls ()
+ && check_file_access (real_path, X_OK, true) < 0)
+ return -1; /* errno is already set. */
+
if (!pgm)
{
if (!p_type_exec)
@@ -1188,12 +1194,6 @@ av::setup (const char *prog_arg, path_conv& real_path, const char *ext,
arg1 = NULL;
}
- /* Check if script is executable. Otherwise we start non-executable
- scripts successfully, which is incorrect behaviour. */
- if (real_path.has_acls ()
- && check_file_access (real_path, X_OK, true) < 0)
- return -1; /* errno is already set. */
-
/* Replace argv[0] with the full path to the script if this is the
first time through the loop. */
replace0_maybe (prog_arg);
--
2.20.1
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