kernel/linux.git/security, branch v5.13.16

bpf: Add lockdown check for probe_write_user helper

2021-08-15T12:01:56+00:00

commit 51e1bb9eeaf7868db56e58f47848e364ab4c4129 upstream. Back then, commit 96ae52279594 ("bpf: Add bpf_probe_write_user BPF helper to be called in tracers") added the bpf_probe_write_user() helper in order to allow to override user space memory. Its original goal was to have a facility to "debug, divert, and manipulate execution of semi-cooperative processes" under CAP_SYS_ADMIN. Write to kernel was explicitly disallowed since it would otherwise tamper with its integrity. One use case was shown in cf9b1199de27 ("samples/bpf: Add test/example of using bpf_probe_write_user bpf helper") where the program DNATs traffic at the time of connect(2) syscall, meaning, it rewrites the arguments to a syscall while they're still in userspace, and before the syscall has a chance to copy the argument into kernel space. These days we have better mechanisms in BPF for achieving the same (e.g. for load-balancers), but without having to write to userspace memory. Of course the bpf_probe_write_user() helper can also be used to abuse many other things for both good or bad purpose. Outside of BPF, there is a similar mechanism for ptrace(2) such as PTRACE_PEEK{TEXT,DATA} and PTRACE_POKE{TEXT,DATA}, but would likely require some more effort. Commit 96ae52279594 explicitly dedicated the helper for experimentation purpose only. Thus, move the helper's availability behind a newly added LOCKDOWN_BPF_WRITE_USER lockdown knob so that the helper is disabled under the "integrity" mode. More fine-grained control can be implemented also from LSM side with this change. Fixes: 96ae52279594 ("bpf: Add bpf_probe_write_user BPF helper to be called in tracers") Signed-off-by: Daniel Borkmann Acked-by: Andrii Nakryiko Signed-off-by: Greg Kroah-Hartman

selinux: correct the return value when loads initial sids

2021-08-12T11:32:22+00:00

commit 4c156084daa8ee70978e4b150b5eb5fc7b1f15be upstream. It should not return 0 when SID 0 is assigned to isids. This patch fixes it. Cc: stable@vger.kernel.org Fixes: e3e0b582c321a ("selinux: remove unused initial SIDs and improve handling") Signed-off-by: Xiu Jianfeng [PM: remove changelog from description] Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

smackfs: restrict bytes count in smk_set_cipso()

2021-07-19T08:04:55+00:00

commit 49ec114a6e62d8d320037ce71c1aaf9650b3cafd upstream. Oops, I failed to update subject line. From 07571157c91b98ce1a4aa70967531e64b78e8346 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Mon, 12 Apr 2021 22:25:06 +0900 Subject: smackfs: restrict bytes count in smk_set_cipso() Commit 7ef4c19d245f3dc2 ("smackfs: restrict bytes count in smackfs write functions") missed that count > SMK_CIPSOMAX check applies to only format == SMK_FIXED24_FMT case. Reported-by: syzbot Signed-off-by: Tetsuo Handa Signed-off-by: Casey Schaufler Signed-off-by: Greg Kroah-Hartman

selinux: use __GFP_NOWARN with GFP_NOWAIT in the AVC

2021-07-19T08:04:38+00:00

[ Upstream commit 648f2c6100cfa18e7dfe43bc0b9c3b73560d623c ] In the field, we have seen lots of allocation failure from the call path below. 06-03 13:29:12.999 1010315 31557 31557 W Binder : 31542_2: page allocation failure: order:0, mode:0x800(GFP_NOWAIT), nodemask=(null),cpuset=background,mems_allowed=0 ... ... 06-03 13:29:12.999 1010315 31557 31557 W Call trace: 06-03 13:29:12.999 1010315 31557 31557 W : dump_backtrace.cfi_jt+0x0/0x8 06-03 13:29:12.999 1010315 31557 31557 W : dump_stack+0xc8/0x14c 06-03 13:29:12.999 1010315 31557 31557 W : warn_alloc+0x158/0x1c8 06-03 13:29:12.999 1010315 31557 31557 W : __alloc_pages_slowpath+0x9d8/0xb80 06-03 13:29:12.999 1010315 31557 31557 W : __alloc_pages_nodemask+0x1c4/0x430 06-03 13:29:12.999 1010315 31557 31557 W : allocate_slab+0xb4/0x390 06-03 13:29:12.999 1010315 31557 31557 W : ___slab_alloc+0x12c/0x3a4 06-03 13:29:12.999 1010315 31557 31557 W : kmem_cache_alloc+0x358/0x5e4 06-03 13:29:12.999 1010315 31557 31557 W : avc_alloc_node+0x30/0x184 06-03 13:29:12.999 1010315 31557 31557 W : avc_update_node+0x54/0x4f0 06-03 13:29:12.999 1010315 31557 31557 W : avc_has_extended_perms+0x1a4/0x460 06-03 13:29:12.999 1010315 31557 31557 W : selinux_file_ioctl+0x320/0x3d0 06-03 13:29:12.999 1010315 31557 31557 W : __arm64_sys_ioctl+0xec/0x1fc 06-03 13:29:12.999 1010315 31557 31557 W : el0_svc_common+0xc0/0x24c 06-03 13:29:12.999 1010315 31557 31557 W : el0_svc+0x28/0x88 06-03 13:29:12.999 1010315 31557 31557 W : el0_sync_handler+0x8c/0xf0 06-03 13:29:12.999 1010315 31557 31557 W : el0_sync+0x1a4/0x1c0 .. .. 06-03 13:29:12.999 1010315 31557 31557 W SLUB : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO) 06-03 13:29:12.999 1010315 31557 31557 W cache : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0 06-03 13:29:12.999 1010315 31557 31557 W node 0 : slabs: 57, objs: 2907, free: 0 06-03 13:29:12.999 1010161 10686 10686 W SLUB : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO) 06-03 13:29:12.999 1010161 10686 10686 W cache : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0 06-03 13:29:12.999 1010161 10686 10686 W node 0 : slabs: 57, objs: 2907, free: 0 06-03 13:29:12.999 1010161 10686 10686 W SLUB : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO) 06-03 13:29:12.999 1010161 10686 10686 W cache : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0 06-03 13:29:12.999 1010161 10686 10686 W node 0 : slabs: 57, objs: 2907, free: 0 06-03 13:29:12.999 1010161 10686 10686 W SLUB : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO) 06-03 13:29:12.999 1010161 10686 10686 W cache : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0 06-03 13:29:12.999 1010161 10686 10686 W node 0 : slabs: 57, objs: 2907, free: 0 06-03 13:29:13.000 1010161 10686 10686 W SLUB : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO) 06-03 13:29:13.000 1010161 10686 10686 W cache : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0 06-03 13:29:13.000 1010161 10686 10686 W node 0 : slabs: 57, objs: 2907, free: 0 06-03 13:29:13.000 1010161 10686 10686 W SLUB : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO) 06-03 13:29:13.000 1010161 10686 10686 W cache : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0 06-03 13:29:13.000 1010161 10686 10686 W node 0 : slabs: 57, objs: 2907, free: 0 06-03 13:29:13.000 1010161 10686 10686 W SLUB : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO) 06-03 13:29:13.000 1010161 10686 10686 W cache : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0 06-03 13:29:13.000 1010161 10686 10686 W node 0 : slabs: 57, objs: 2907, free: 0 06-03 13:29:13.000 10230 30892 30892 W SLUB : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO) 06-03 13:29:13.000 10230 30892 30892 W cache : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0 06-03 13:29:13.000 10230 30892 30892 W node 0 : slabs: 57, objs: 2907, free: 0 06-03 13:29:13.000 10230 30892 30892 W SLUB : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO) 06-03 13:29:13.000 10230 30892 30892 W cache : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0 Based on [1], selinux is tolerate for failure of memory allocation. Then, use __GFP_NOWARN together. [1] 476accbe2f6e ("selinux: use GFP_NOWAIT in the AVC kmem_caches") Signed-off-by: Minchan Kim [PM: subj fix, line wraps, normalized commit refs] Signed-off-by: Paul Moore Signed-off-by: Sasha Levin

evm: fix writing /evm overflow

2021-07-14T15:06:40+00:00

[ Upstream commit 49219d9b8785ba712575c40e48ce0f7461254626 ] EVM_SETUP_COMPLETE is defined as 0x80000000, which is larger than INT_MAX. The "-fno-strict-overflow" compiler option properly prevents signaling EVM that the EVM policy setup is complete. Define and read an unsigned int. Fixes: f00d79750712 ("EVM: Allow userspace to signal an RSA key has been loaded") Signed-off-by: Mimi Zohar Signed-off-by: Sasha Levin

ima: Don't remove security.ima if file must not be appraised

2021-07-14T15:06:24+00:00

[ Upstream commit ed1b472fc15aeaa20ddeeb93fd25190014e50d17 ] Files might come from a remote source and might have xattrs, including security.ima. It should not be IMA task to decide whether security.ima should be kept or not. This patch removes the removexattr() system call in ima_inode_post_setattr(). Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar Signed-off-by: Sasha Levin

evm: Refuse EVM_ALLOW_METADATA_WRITES only if an HMAC key is loaded

2021-07-14T15:06:18+00:00

commit 9acc89d31f0c94c8e573ed61f3e4340bbd526d0c upstream. EVM_ALLOW_METADATA_WRITES is an EVM initialization flag that can be set to temporarily disable metadata verification until all xattrs/attrs necessary to verify an EVM portable signature are copied to the file. This flag is cleared when EVM is initialized with an HMAC key, to avoid that the HMAC is calculated on unverified xattrs/attrs. Currently EVM unnecessarily denies setting this flag if EVM is initialized with a public key, which is not a concern as it cannot be used to trust xattrs/attrs updates. This patch removes this limitation. Fixes: ae1ba1676b88e ("EVM: Allow userland to permit modification of EVM-protected metadata") Signed-off-by: Roberto Sassu Cc: stable@vger.kernel.org # 4.16.x Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman

evm: Execute evm_inode_init_security() only when an HMAC key is loaded

2021-07-14T15:06:18+00:00

commit 9eea2904292c2d8fa98df141d3bf7c41ec9dc1b5 upstream. evm_inode_init_security() requires an HMAC key to calculate the HMAC on initial xattrs provided by LSMs. However, it checks generically whether a key has been loaded, including also public keys, which is not correct as public keys are not suitable to calculate the HMAC. Originally, support for signature verification was introduced to verify a possibly immutable initial ram disk, when no new files are created, and to switch to HMAC for the root filesystem. By that time, an HMAC key should have been loaded and usable to calculate HMACs for new files. More recently support for requiring an HMAC key was removed from the kernel, so that signature verification can be used alone. Since this is a legitimate use case, evm_inode_init_security() should not return an error when no HMAC key has been loaded. This patch fixes this problem by replacing the evm_key_loaded() check with a check of the EVM_INIT_HMAC flag in evm_initialized. Fixes: 26ddabfe96b ("evm: enable EVM when X509 certificate is loaded") Signed-off-by: Roberto Sassu Cc: stable@vger.kernel.org # 4.5.x Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman

trusted-keys: match tpm_get_ops on all return paths

2021-05-12T19:36:37+00:00

The `tpm_get_ops` call at the beginning of the function is not paired with a `tpm_put_ops` on this return path. Cc: stable@vger.kernel.org Fixes: f2219745250f ("security: keys: trusted: use ASN.1 TPM2 key format for the blobs") Reported-by: Dan Carpenter Signed-off-by: Ben Boeckel Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen

KEYS: trusted: Fix memory leak on object td

2021-05-12T19:36:36+00:00

Two error return paths are neglecting to free allocated object td, causing a memory leak. Fix this by returning via the error return path that securely kfree's td. Fixes clang scan-build warning: security/keys/trusted-keys/trusted_tpm1.c:496:10: warning: Potential memory leak [unix.Malloc] Cc: stable@vger.kernel.org Fixes: 5df16caada3f ("KEYS: trusted: Fix incorrect handling of tpm_get_random()") Signed-off-by: Colin Ian King Reviewed-by: Nick Desaulniers Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen