From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Josh Poimboeuf <jpoimboe@redhat.com>,
Borislav Petkov <bp@suse.de>,
Thomas Gleixner <tglx@linutronix.de>,
Frank van der Linden <fllinden@amazon.com>
Subject: [PATCH 5.15 06/58] x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting
Date: Thu, 10 Mar 2022 15:18:55 +0100 [thread overview]
Message-ID: <20220310140813.169073156@linuxfoundation.org> (raw)
In-Reply-To: <20220310140812.983088611@linuxfoundation.org>
From: Josh Poimboeuf <jpoimboe@redhat.com>
commit 44a3918c8245ab10c6c9719dd12e7a8d291980d8 upstream.
With unprivileged eBPF enabled, eIBRS (without retpoline) is vulnerable
to Spectre v2 BHB-based attacks.
When both are enabled, print a warning message and report it in the
'spectre_v2' sysfs vulnerabilities file.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
[fllinden@amazon.com: backported to 5.15]
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/cpu/bugs.c | 35 +++++++++++++++++++++++++++++------
include/linux/bpf.h | 12 ++++++++++++
kernel/sysctl.c | 7 +++++++
3 files changed, 48 insertions(+), 6 deletions(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -16,6 +16,7 @@
#include <linux/prctl.h>
#include <linux/sched/smt.h>
#include <linux/pgtable.h>
+#include <linux/bpf.h>
#include <asm/spec-ctrl.h>
#include <asm/cmdline.h>
@@ -650,6 +651,16 @@ static inline const char *spectre_v2_mod
static inline const char *spectre_v2_module_string(void) { return ""; }
#endif
+#define SPECTRE_V2_EIBRS_EBPF_MSG "WARNING: Unprivileged eBPF is enabled with eIBRS on, data leaks possible via Spectre v2 BHB attacks!\n"
+
+#ifdef CONFIG_BPF_SYSCALL
+void unpriv_ebpf_notify(int new_state)
+{
+ if (spectre_v2_enabled == SPECTRE_V2_EIBRS && !new_state)
+ pr_err(SPECTRE_V2_EIBRS_EBPF_MSG);
+}
+#endif
+
static inline bool match_option(const char *arg, int arglen, const char *opt)
{
int len = strlen(opt);
@@ -994,6 +1005,9 @@ static void __init spectre_v2_select_mit
break;
}
+ if (mode == SPECTRE_V2_EIBRS && unprivileged_ebpf_enabled())
+ pr_err(SPECTRE_V2_EIBRS_EBPF_MSG);
+
if (spectre_v2_in_eibrs_mode(mode)) {
/* Force it so VMEXIT will restore correctly */
x86_spec_ctrl_base |= SPEC_CTRL_IBRS;
@@ -1780,6 +1794,20 @@ static char *ibpb_state(void)
return "";
}
+static ssize_t spectre_v2_show_state(char *buf)
+{
+ if (spectre_v2_enabled == SPECTRE_V2_EIBRS && unprivileged_ebpf_enabled())
+ return sprintf(buf, "Vulnerable: Unprivileged eBPF enabled\n");
+
+ return sprintf(buf, "%s%s%s%s%s%s\n",
+ spectre_v2_strings[spectre_v2_enabled],
+ ibpb_state(),
+ boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "",
+ stibp_state(),
+ boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "",
+ spectre_v2_module_string());
+}
+
static ssize_t srbds_show_state(char *buf)
{
return sprintf(buf, "%s\n", srbds_strings[srbds_mitigation]);
@@ -1805,12 +1833,7 @@ static ssize_t cpu_show_common(struct de
return sprintf(buf, "%s\n", spectre_v1_strings[spectre_v1_mitigation]);
case X86_BUG_SPECTRE_V2:
- return sprintf(buf, "%s%s%s%s%s%s\n", spectre_v2_strings[spectre_v2_enabled],
- ibpb_state(),
- boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "",
- stibp_state(),
- boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "",
- spectre_v2_module_string());
+ return spectre_v2_show_state(buf);
case X86_BUG_SPEC_STORE_BYPASS:
return sprintf(buf, "%s\n", ssb_strings[ssb_mode]);
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1666,6 +1666,12 @@ bool bpf_prog_has_kfunc_call(const struc
const struct btf_func_model *
bpf_jit_find_kfunc_model(const struct bpf_prog *prog,
const struct bpf_insn *insn);
+
+static inline bool unprivileged_ebpf_enabled(void)
+{
+ return !sysctl_unprivileged_bpf_disabled;
+}
+
#else /* !CONFIG_BPF_SYSCALL */
static inline struct bpf_prog *bpf_prog_get(u32 ufd)
{
@@ -1884,6 +1890,12 @@ bpf_jit_find_kfunc_model(const struct bp
{
return NULL;
}
+
+static inline bool unprivileged_ebpf_enabled(void)
+{
+ return false;
+}
+
#endif /* CONFIG_BPF_SYSCALL */
void __bpf_free_used_btfs(struct bpf_prog_aux *aux,
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -228,6 +228,10 @@ static int bpf_stats_handler(struct ctl_
return ret;
}
+void __weak unpriv_ebpf_notify(int new_state)
+{
+}
+
static int bpf_unpriv_handler(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
@@ -245,6 +249,9 @@ static int bpf_unpriv_handler(struct ctl
return -EPERM;
*(int *)table->data = unpriv_enable;
}
+
+ unpriv_ebpf_notify(unpriv_enable);
+
return ret;
}
#endif /* CONFIG_BPF_SYSCALL && CONFIG_SYSCTL */
next prev parent reply other threads:[~2022-03-10 14:33 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-10 14:18 [PATCH 5.15 00/58] 5.15.28-rc2 review Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 01/58] slip: fix macro redefine warning Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 02/58] x86,bugs: Unconditionally allow spectre_v2=retpoline,amd Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 03/58] x86/speculation: Rename RETPOLINE_AMD to RETPOLINE_LFENCE Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 04/58] x86/speculation: Add eIBRS + Retpoline options Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 05/58] Documentation/hw-vuln: Update spectre doc Greg Kroah-Hartman
2022-03-10 14:18 ` Greg Kroah-Hartman [this message]
2022-03-10 14:18 ` [PATCH 5.15 07/58] x86/speculation: Use generic retpoline by default on AMD Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 08/58] x86/speculation: Update link to AMD speculation whitepaper Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 09/58] x86/speculation: Warn about Spectre v2 LFENCE mitigation Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 10/58] x86/speculation: Warn about eIBRS + LFENCE + Unprivileged eBPF + SMT Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 11/58] ARM: report Spectre v2 status through sysfs Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 12/58] ARM: early traps initialisation Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 13/58] ARM: use LOADADDR() to get load address of sections Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 14/58] ARM: Spectre-BHB workaround Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 15/58] ARM: include unprivileged BPF status in Spectre V2 reporting Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 16/58] arm64: Add Neoverse-N2, Cortex-A710 CPU part definition Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 17/58] arm64: Add HWCAP for self-synchronising virtual counter Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 18/58] arm64: Add Cortex-X2 CPU part definition Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 19/58] arm64: add ID_AA64ISAR2_EL1 sys register Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 20/58] arm64: cpufeature: add HWCAP for FEAT_AFP Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 21/58] arm64: cpufeature: add HWCAP for FEAT_RPRES Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 22/58] arm64: entry.S: Add ventry overflow sanity checks Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 23/58] arm64: spectre: Rename spectre_v4_patch_fw_mitigation_conduit Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 24/58] KVM: arm64: Allow indirect vectors to be used without SPECTRE_V3A Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 25/58] arm64: entry: Make the trampoline cleanup optional Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 26/58] arm64: entry: Free up another register on kptis tramp_exit path Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 27/58] arm64: entry: Move the trampoline data page before the text page Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 28/58] arm64: entry: Allow tramp_alias to access symbols after the 4K boundary Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 29/58] arm64: entry: Dont assume tramp_vectors is the start of the vectors Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 30/58] arm64: entry: Move trampoline macros out of ifdefd section Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 31/58] arm64: entry: Make the kpti trampolines kpti sequence optional Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 32/58] arm64: entry: Allow the trampoline text to occupy multiple pages Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 33/58] arm64: entry: Add non-kpti __bp_harden_el1_vectors for mitigations Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 34/58] arm64: entry: Add vectors that have the bhb mitigation sequences Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 35/58] arm64: entry: Add macro for reading symbol addresses from the trampoline Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 36/58] arm64: Add percpu vectors for EL1 Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 37/58] arm64: proton-pack: Report Spectre-BHB vulnerabilities as part of Spectre-v2 Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 38/58] arm64: Mitigate spectre style branch history side channels Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 39/58] KVM: arm64: Allow SMCCC_ARCH_WORKAROUND_3 to be discovered and migrated Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 40/58] arm64: Use the clearbhb instruction in mitigations Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 41/58] arm64: proton-pack: Include unprivileged eBPF status in Spectre v2 mitigation reporting Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 42/58] ARM: fix build error when BPF_SYSCALL is disabled Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 43/58] ARM: fix co-processor register typo Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 44/58] ARM: Do not use NOCROSSREFS directive with ld.lld Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 45/58] arm64: Do not include __READ_ONCE() block in assembly files Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 46/58] ARM: fix build warning in proc-v7-bugs.c Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 47/58] xen/xenbus: dont let xenbus_grant_ring() remove grants in error case Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 48/58] xen/grant-table: add gnttab_try_end_foreign_access() Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 49/58] xen/blkfront: dont use gnttab_query_foreign_access() for mapped status Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 50/58] xen/netfront: " Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 51/58] xen/scsifront: " Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 52/58] xen/gntalloc: dont use gnttab_query_foreign_access() Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 53/58] xen: remove gnttab_query_foreign_access() Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 54/58] xen/9p: use alloc/free_pages_exact() Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 55/58] xen/pvcalls: " Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 56/58] xen/gnttab: fix gnttab_end_foreign_access() without page specified Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 57/58] xen/netfront: react properly to failing gnttab_end_foreign_access_ref() Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 58/58] Revert "ACPI: PM: s2idle: Cancel wakeup before dispatching EC GPE" Greg Kroah-Hartman
2022-03-10 18:48 ` [PATCH 5.15 00/58] 5.15.28-rc2 review Jon Hunter
2022-03-10 19:04 ` Fox Chen
2022-03-10 19:32 ` Shuah Khan
2022-03-10 22:12 ` Florian Fainelli
2022-03-11 1:03 ` Guenter Roeck
2022-03-11 7:34 ` Ron Economos
2022-03-11 8:27 ` Bagas Sanjaya
2022-03-11 10:08 ` Sudip Mukherjee
2022-03-11 10:26 ` Anders Roxell
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