[cifs-utils PATCH 1/2] cifscreds: better error handling when key_search fails

[Jeff Layton]

If we ended up getting a bogus string that would have overflowed, then
make key_search set errno to EINVAL before returning. The callers can
then test to see if the returned error is what was expected or something
else and handle it appropriately.

Cc: Sebastian Krahmer <krahmer-***@public.gmane.org>
Signed-off-by: Jeff Layton <jlayton-***@public.gmane.org>
---
cifscreds.c | 9 +++++++++
cifskey.c | 5 ++++-
pam_cifscreds.c | 9 +++++++++
3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/cifscreds.c b/cifscreds.c
index fa05dc88b0e0..64d55b0cac0e 100644
--- a/cifscreds.c
+++ b/cifscreds.c
@@ -188,6 +188,15 @@ static int cifscreds_add(struct cmdarg *arg)
return EXIT_FAILURE;
}

+ switch(errno) {
+ case ENOKEY:
+ /* success */
+ break;
+ default:
+ printf("Key search failed: %s\n", strerror(errno));
+ return EXIT_FAILURE;
+ }
+
currentaddress = nextaddress;
if (currentaddress) {
*(currentaddress - 1) = ',';
diff --git a/cifskey.c b/cifskey.c
index e89cacf171f2..4f01ed0e10bd 100644
--- a/cifskey.c
+++ b/cifskey.c
@@ -20,6 +20,7 @@
#include <sys/types.h>
#include <keyutils.h>
#include <stdio.h>
+#include <errno.h>
#include "cifskey.h"
#include "resolve_host.h"

@@ -29,8 +30,10 @@ key_search(const char *addr, char keytype)
{
char desc[INET6_ADDRSTRLEN + sizeof(KEY_PREFIX) + 4];

- if (snprintf(desc, sizeof(desc), "%s:%c:%s", KEY_PREFIX, keytype, addr) >= (int)sizeof(desc))
+ if (snprintf(desc, sizeof(desc), "%s:%c:%s", KEY_PREFIX, keytype, addr) >= (int)sizeof(desc)) {
+ errno = EINVAL;
return -1;
+ }

return keyctl_search(DEST_KEYRING, CIFS_KEY_TYPE, desc, 0);
}
diff --git a/pam_cifscreds.c b/pam_cifscreds.c
index e0d8a554510e..fb23117953f0 100644
--- a/pam_cifscreds.c
+++ b/pam_cifscreds.c
@@ -206,6 +206,15 @@ static int cifscreds_pam_add(pam_handle_t *ph, const char *user, const char *pas
return PAM_SERVICE_ERR;
}

+ switch(errno) {
+ case ENOKEY:
+ break;
+ default:
+ pam_syslog(ph, LOG_ERR, "Unable to search keyring for %s (%s)",
+ currentaddress, strerror(errno));
+ return PAM_SERVICE_ERR;
+ }
+
currentaddress = nextaddress;
if (currentaddress) {
*(currentaddress - 1) = ',';