Revert "Fix bug #7067 - Linux asynchronous IO (aio) can cause smbd to fail to respond to a read or write."

This reverts commit a6ae7a552f851a399991262377cc0e062e40ac20.

This fixes bug #7222 (All users have full rigths on all shares) (CVE-2010-0728).
(cherry picked from commit 1c9494c76cc9686c61e0966f38528d3318f3176f)

3 files changed, 5 insertions, 71 deletions

diff --git a/source3/include/smb.h b/source3/include/smb.h
index 8d1e148259..8674629188 100644
--- a/source3/include/smb.h
+++ b/source3/include/smb.h
@@ -1724,8 +1724,7 @@ minimum length == 24.
 enum smbd_capability {
     KERNEL_OPLOCK_CAPABILITY,
     DMAPI_ACCESS_CAPABILITY,
-    LEASE_CAPABILITY,
-    KILL_CAPABILITY
+    LEASE_CAPABILITY
 };
 
 /*
diff --git a/source3/lib/system.c b/source3/lib/system.c
index 58240a34a8..5aab4417a9 100644
--- a/source3/lib/system.c
+++ b/source3/lib/system.c
@@ -908,11 +908,6 @@ char *sys_getwd(char *s)
 
 #if defined(HAVE_POSIX_CAPABILITIES)
 
-/* This define hasn't made it into the glibc capabilities header yet. */
-#ifndef SECURE_NO_SETUID_FIXUP
-#define SECURE_NO_SETUID_FIXUP          2
-#endif
-
 /**************************************************************************
  Try and abstract process capabilities (for systems that have them).
 ****************************************************************************/
@@ -943,32 +938,6 @@ static bool set_process_capability(enum smbd_capability capability,
 	}
 #endif
 
-#if defined(HAVE_PRCTL) && defined(PR_SET_SECUREBITS) && defined(SECURE_NO_SETUID_FIXUP)
-        /* New way of setting capabilities as "sticky". */
-
-	/*
-	 * Use PR_SET_SECUREBITS to prevent setresuid()
-	 * atomically dropping effective capabilities on
-	 * uid change. Only available in Linux kernels
-	 * 2.6.26 and above.
-	 *
-	 * See here:
-	 * http://www.kernel.org/doc/man-pages/online/pages/man7/capabilities.7.html
-	 * for details.
-	 *
-	 * Specifically the CAP_KILL capability we need
-	 * to allow Linux threads under different euids
-	 * to send signals to each other.
-	 */
-
-	if (prctl(PR_SET_SECUREBITS, 1 << SECURE_NO_SETUID_FIXUP)) {
-		DEBUG(0,("set_process_capability: "
-			"prctl PR_SET_SECUREBITS failed with error %s\n",
-			strerror(errno) ));
-		return false;
-	}
-#endif
-
 	cap = cap_get_proc();
 	if (cap == NULL) {
 		DEBUG(0,("set_process_capability: cap_get_proc failed: %s\n",
@@ -997,11 +966,6 @@ static bool set_process_capability(enum smbd_capability capability,
 			cap_vals[num_cap_vals++] = CAP_LEASE;
 #endif
 			break;
-		case KILL_CAPABILITY:
-#ifdef CAP_KILL
-			cap_vals[num_cap_vals++] = CAP_KILL;
-#endif
-			break;
 	}
 
 	SMB_ASSERT(num_cap_vals <= ARRAY_SIZE(cap_vals));
@@ -1011,37 +975,16 @@ static bool set_process_capability(enum smbd_capability capability,
 		return True;
 	}
 
-	/*
-	 * Ensure the capability is effective. We assume that as a root
-	 * process it's always permitted.
-	 */
-
-	if (cap_set_flag(cap, CAP_EFFECTIVE, num_cap_vals, cap_vals,
-			enable ? CAP_SET : CAP_CLEAR) == -1) {
-		DEBUG(0, ("set_process_capability: cap_set_flag effective "
-			"failed (%d): %s\n",
-			(int)capability,
-			strerror(errno)));
-		cap_free(cap);
-		return false;
-	}
+	cap_set_flag(cap, CAP_EFFECTIVE, num_cap_vals, cap_vals,
+		enable ? CAP_SET : CAP_CLEAR);
 
 	/* We never want to pass capabilities down to our children, so make
 	 * sure they are not inherited.
 	 */
-	if (cap_set_flag(cap, CAP_INHERITABLE, num_cap_vals,
-			cap_vals, CAP_CLEAR) == -1) {
-		DEBUG(0, ("set_process_capability: cap_set_flag inheritable "
-			"failed (%d): %s\n",
-			(int)capability,
-			strerror(errno)));
-		cap_free(cap);
-		return false;
-	}
+	cap_set_flag(cap, CAP_INHERITABLE, num_cap_vals, cap_vals, CAP_CLEAR);
 
 	if (cap_set_proc(cap) == -1) {
-		DEBUG(0, ("set_process_capability: cap_set_flag (%d) failed: %s\n",
-			(int)capability,
+		DEBUG(0, ("set_process_capability: cap_set_proc failed: %s\n",
 			strerror(errno)));
 		cap_free(cap);
 		return False;
diff --git a/source3/smbd/server.c b/source3/smbd/server.c
index d88679c95f..f685385043 100644
--- a/source3/smbd/server.c
+++ b/source3/smbd/server.c
@@ -1081,14 +1081,6 @@ extern void build_options(bool screen);
 	gain_root_privilege();
 	gain_root_group_privilege();
 
-	/*
-	 * Ensure we have CAP_KILL capability set on Linux,
-	 * where we need this to communicate with threads.
-	 * This is inherited by new threads, but not by new
-	 * processes across exec().
-	 */
-	set_effective_capability(KILL_CAPABILITY);
-
 	fault_setup((void (*)(void *))exit_server_fault);
 	dump_core_setup("smbd");