linux/security/commoncap.c, branch v2.6.32

Security/SELinux: seperate lsm specific mmap_min_addr

2009-08-05T23:02:23Z

Currently SELinux enforcement of controls on the ability to map low memory is determined by the mmap_min_addr tunable. This patch causes SELinux to ignore the tunable and instead use a seperate Kconfig option specific to how much space the LSM should protect. The tunable will now only control the need for CAP_SYS_RAWIO and SELinux permissions will always protect the amount of low memory designated by CONFIG_LSM_MMAP_MIN_ADDR. This allows users who need to disable the mmap_min_addr controls (usual reason being they run WINE as a non-root user) to do so and still have SELinux controls preventing confined domains (like a web server) from being able to map some area of low memory. Signed-off-by: Eric Paris Signed-off-by: James Morris

Capabilities: move cap_file_mmap to commoncap.c

2009-08-05T23:02:17Z

Currently we duplicate the mmap_min_addr test in cap_file_mmap and in security_file_mmap if !CONFIG_SECURITY. This patch moves cap_file_mmap into commoncap.c and then calls that function directly from security_file_mmap ifndef CONFIG_SECURITY like all of the other capability checks are done. Signed-off-by: Eric Paris Acked-by: Serge Hallyn Signed-off-by: James Morris

security: rename ptrace_may_access => ptrace_access_check

2009-06-24T14:18:05Z

The ->ptrace_may_access() methods are named confusingly - the real ptrace_may_access() returns a bool, while these security checks have a retval convention. Rename it to ptrace_access_check, to reduce the confusion factor. [ Impact: cleanup, no code changed ] Signed-off-by: Ingo Molnar Signed-off-by: James Morris

Merge branch 'master' into next

2009-05-08T07:56:47Z

cap_prctl: don't set error to 0 at 'no_change'

2009-04-08T23:12:03Z

One-liner: capsh --print is broken without this patch. In certain cases, cap_prctl returns error > 0 for success. However, the 'no_change' label was always setting error to 0. As a result, for example, 'prctl(CAP_BSET_READ, N)' would always return 0. It should return 1 if a process has N in its bounding set (as by default it does). I'm keeping the no_change label even though it's now functionally the same as 'error'. Signed-off-by: Serge Hallyn Acked-by: David Howells Signed-off-by: James Morris

don't raise all privs on setuid-root file with fE set (v2)

2009-04-03T00:49:31Z

Distributions face a backward compatibility problem with starting to use file capabilities. For instance, removing setuid root from ping and doing setcap cap_net_raw=pe means that booting with an older kernel or one compiled without file capabilities means ping won't work for non-root users. In order to replace the setuid root bit on a capability-unaware program, one has to set the effective, or legacy, file capability, which makes the capability effective immediately. This patch uses the legacy bit as a queue to not automatically add full privilege to a setuid-root program. So, with this patch, an ordinary setuid-root program will run with privilege. But if /bin/ping has both setuid-root and cap_net_raw in fP and fE, then ping (when run by non-root user) will not run with only cap_net_raw. Changelog: Apr 2 2009: Print a message once when such a binary is loaded, as per James Morris' suggestion. Apr 2 2009: Fix the condition to only catch uid!=0 && euid==0. Signed-off-by: Serge E. Hallyn Acked-by: Casey Schaufler Signed-off-by: James Morris

Merge branch 'next' into for-linus

2009-01-06T22:58:22Z

CRED: Fix regression in cap_capable() as shown up by sys_faccessat() [ver #3]

2009-01-06T22:38:48Z

Fix a regression in cap_capable() due to: commit 3b11a1decef07c19443d24ae926982bc8ec9f4c0 Author: David Howells Date: Fri Nov 14 10:39:26 2008 +1100 CRED: Differentiate objective and effective subjective credentials on a task The problem is that the above patch allows a process to have two sets of credentials, and for the most part uses the subjective credentials when accessing current's creds. There is, however, one exception: cap_capable(), and thus capable(), uses the real/objective credentials of the target task, whether or not it is the current task. Ordinarily this doesn't matter, since usually the two cred pointers in current point to the same set of creds. However, sys_faccessat() makes use of this facility to override the credentials of the calling process to make its test, without affecting the creds as seen from other processes. One of the things sys_faccessat() does is to make an adjustment to the effective capabilities mask, which cap_capable(), as it stands, then ignores. The affected capability check is in generic_permission(): if (!(mask & MAY_EXEC) || execute_ok(inode)) if (capable(CAP_DAC_OVERRIDE)) return 0; This change passes the set of credentials to be tested down into the commoncap and SELinux code. The security functions called by capable() and has_capability() select the appropriate set of credentials from the process being checked. This can be tested by compiling the following program from the XFS testsuite: /* * t_access_root.c - trivial test program to show permission bug. * * Written by Michael Kerrisk - copyright ownership not pursued. * Sourced from: http://linux.derkeiler.com/Mailing-Lists/Kernel/2003-10/6030.html */ #include #include #include #include #include #include #define UID 500 #define GID 100 #define PERM 0 #define TESTPATH "/tmp/t_access" static void errExit(char *msg) { perror(msg); exit(EXIT_FAILURE); } /* errExit */ static void accessTest(char *file, int mask, char *mstr) { printf("access(%s, %s) returns %d\n", file, mstr, access(file, mask)); } /* accessTest */ int main(int argc, char *argv[]) { int fd, perm, uid, gid; char *testpath; char cmd[PATH_MAX + 20]; testpath = (argc > 1) ? argv[1] : TESTPATH; perm = (argc > 2) ? strtoul(argv[2], NULL, 8) : PERM; uid = (argc > 3) ? atoi(argv[3]) : UID; gid = (argc > 4) ? atoi(argv[4]) : GID; unlink(testpath); fd = open(testpath, O_RDWR | O_CREAT, 0); if (fd == -1) errExit("open"); if (fchown(fd, uid, gid) == -1) errExit("fchown"); if (fchmod(fd, perm) == -1) errExit("fchmod"); close(fd); snprintf(cmd, sizeof(cmd), "ls -l %s", testpath); system(cmd); if (seteuid(uid) == -1) errExit("seteuid"); accessTest(testpath, 0, "0"); accessTest(testpath, R_OK, "R_OK"); accessTest(testpath, W_OK, "W_OK"); accessTest(testpath, X_OK, "X_OK"); accessTest(testpath, R_OK | W_OK, "R_OK | W_OK"); accessTest(testpath, R_OK | X_OK, "R_OK | X_OK"); accessTest(testpath, W_OK | X_OK, "W_OK | X_OK"); accessTest(testpath, R_OK | W_OK | X_OK, "R_OK | W_OK | X_OK"); exit(EXIT_SUCCESS); } /* main */ This can be run against an Ext3 filesystem as well as against an XFS filesystem. If successful, it will show: [root@andromeda src]# ./t_access_root /tmp/xxx 0 4043 4043 ---------- 1 dhowells dhowells 0 2008-12-31 03:00 /tmp/xxx access(/tmp/xxx, 0) returns 0 access(/tmp/xxx, R_OK) returns 0 access(/tmp/xxx, W_OK) returns 0 access(/tmp/xxx, X_OK) returns -1 access(/tmp/xxx, R_OK | W_OK) returns 0 access(/tmp/xxx, R_OK | X_OK) returns -1 access(/tmp/xxx, W_OK | X_OK) returns -1 access(/tmp/xxx, R_OK | W_OK | X_OK) returns -1 If unsuccessful, it will show: [root@andromeda src]# ./t_access_root /tmp/xxx 0 4043 4043 ---------- 1 dhowells dhowells 0 2008-12-31 02:56 /tmp/xxx access(/tmp/xxx, 0) returns 0 access(/tmp/xxx, R_OK) returns -1 access(/tmp/xxx, W_OK) returns -1 access(/tmp/xxx, X_OK) returns -1 access(/tmp/xxx, R_OK | W_OK) returns -1 access(/tmp/xxx, R_OK | X_OK) returns -1 access(/tmp/xxx, W_OK | X_OK) returns -1 access(/tmp/xxx, R_OK | W_OK | X_OK) returns -1 I've also tested the fix with the SELinux and syscalls LTP testsuites. Signed-off-by: David Howells Tested-by: J. Bruce Fields Acked-by: Serge Hallyn Signed-off-by: James Morris

Revert "CRED: Fix regression in cap_capable() as shown up by sys_faccessat() [ver #2]"

2009-01-06T22:21:54Z

This reverts commit 14eaddc967b16017d4a1a24d2be6c28ecbe06ed8. David has a better version to come.

inode->i_op is never NULL

2009-01-05T16:54:28Z

We used to have rather schizophrenic set of checks for NULL ->i_op even though it had been eliminated years ago. You'd need to go out of your way to set it to NULL explicitly _and_ a bunch of code would die on such inodes anyway. After killing two remaining places that still did that bogosity, all that crap can go away. Signed-off-by: Al Viro