path: root/fs/exec.c
diff options
authorKees Cook <keescook@chromium.org>2013-11-12 15:11:17 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-11-13 12:09:33 +0900
commitd049f74f2dbe71354d43d393ac3a188947811348 (patch)
tree7d3b6d88824a0584ae3c8d86782d69bf331d6cef /fs/exec.c
parent1c3fc3e5cc8a81d21b199cb739d5d9c51f3688f4 (diff)
exec/ptrace: fix get_dumpable() incorrect tests
The get_dumpable() return value is not boolean. Most users of the function actually want to be testing for non-SUID_DUMP_USER(1) rather than SUID_DUMP_DISABLE(0). The SUID_DUMP_ROOT(2) is also considered a protected state. Almost all places did this correctly, excepting the two places fixed in this patch. Wrong logic: if (dumpable == SUID_DUMP_DISABLE) { /* be protective */ } or if (dumpable == 0) { /* be protective */ } or if (!dumpable) { /* be protective */ } Correct logic: if (dumpable != SUID_DUMP_USER) { /* be protective */ } or if (dumpable != 1) { /* be protective */ } Without this patch, if the system had set the sysctl fs/suid_dumpable=2, a user was able to ptrace attach to processes that had dropped privileges to that user. (This may have been partially mitigated if Yama was enabled.) The macros have been moved into the file that declares get/set_dumpable(), which means things like the ia64 code can see them too. CVE-2013-2929 Reported-by: Vasily Kulikov <segoon@openwall.com> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/exec.c')
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 2ea437e5acf..12120620f04 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1669,6 +1669,12 @@ int __get_dumpable(unsigned long mm_flags)
return (ret > SUID_DUMP_USER) ? SUID_DUMP_ROOT : ret;
+ * This returns the actual value of the suid_dumpable flag. For things
+ * that are using this for checking for privilege transitions, it must
+ * test against SUID_DUMP_USER rather than treating it as a boolean
+ * value.
+ */
int get_dumpable(struct mm_struct *mm)
return __get_dumpable(mm->flags);