Jann Horn 3675f052b4 Smack: Don't ignore other bprm->unsafe flags if LSM_UNSAFE_PTRACE is set ... There is a logic bug in the current smack_bprm_set_creds(): If LSM_UNSAFE_PTRACE is set, but the ptrace state is deemed to be acceptable (e.g. because the ptracer detached in the meantime), the other ->unsafe flags aren't checked. As far as I can tell, this means that something like the following could work (but I haven't tested it): - task A: create task B with fork() - task B: set NO_NEW_PRIVS - task B: install a seccomp filter that makes open() return 0 under some conditions - task B: replace fd 0 with a malicious library - task A: attach to task B with PTRACE_ATTACH - task B: execve() a file with an SMACK64EXEC extended attribute - task A: while task B is still in the middle of execve(), exit (which destroys the ptrace relationship) Make sure that if any flags other than LSM_UNSAFE_PTRACE are set in bprm->unsafe, we reject the execve(). Cc: stable@vger.kernel.org Fixes: 5663884caa ("Smack: unify all ptrace accesses in the smack") Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>		2019-09-04 09:36:57 -07:00
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Kconfig	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
Makefile	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
smack.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 372	2019-06-05 17:37:10 +02:00
smack_access.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 372	2019-06-05 17:37:10 +02:00
smack_lsm.c	Smack: Don't ignore other bprm->unsafe flags if LSM_UNSAFE_PTRACE is set	2019-09-04 09:36:57 -07:00
smack_netfilter.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500	2019-06-19 17:09:55 +02:00
smackfs.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 372	2019-06-05 17:37:10 +02:00